University of New South Wales Faculty of Civil and Environmental Engineering COORDINATED CADASTRE PUTTING THE PUZZLE BACK TOGETHER BY Jason Terry z3377544 In the fulfilment of GMAT4015 October 2014 Supervised by Dr Bruce Harvey Acknowledgments The author wishes to acknowledge Dr Bruce Harvey, for his support and assistance in this project. His Knowledge and guidance was paramount to the success of the project We also acknowledge that LPI kindly provided the DCDB of Kogarah LGA.
The DCDB is (c) Land and Property Information 2014. The DCDB was used
in part of the research in this thesis for research and educational purposes
only.
Coordinated Cadastre: Putting The Puzzle Back Together Jason Terry 2 PLAGIARISM DECLARATION Coordinated Cadastre: Putting The Puzzle Back Together Jason Terry 3 TABLE OF CONTENTS Abstract ................................................................................................................................. 7 1 introduction ..................................................................................................................... 8 1.1 The Cadastre ............................................................................................................ 8 1.1.1 Coordinated Cadastre ................................................................................................... 9 1.1.2 DCDB ................................................................................................................................. 10 1.2 Survey Accurate DCDB ....................................................................................... 12 1.3 Legal Coordinated Cadastre ............................................................................. 15 1.4 3D Cadastres ......................................................................................................... 19 2 Challenges For Creating The Digital Cadastre ................................................... 20 2.1The data Entry process ....................................................................................... 20 2.1.1 Crowd sourcing ............................................................................................................. 21 2.1.2 LandXML .......................................................................................................................... 22 2.2 Old System Title ................................................................................................... 23 3 Hurstville Case Study ................................................................................................. 23 3.1 A Brief History ...................................................................................................... 24 3.2 The case study ...................................................................................................... 25 3.2.1 The Site ............................................................................................................................. 26 3.3 The Data Set ........................................................................................................... 26 3.3.1 Fixit 4 ................................................................................................................................ 27 3.3.2 Variance Factor and Standard Deviations ......................................................... 27 3.3.3 Outliers ............................................................................................................................. 31 3.4 Problems in the Model ....................................................................................... 31 Coordinated Cadastre: Putting The Puzzle Back Together Jason Terry 4 3.4.1 Cadastral Discrepancies ............................................................................................ 32 3.5 Recent DP’s ............................................................................................................ 33 3.6Additional Information ...................................................................................... 35 3.6.1Reference marks ............................................................................................................ 35 3.6.2 The Field Survey ........................................................................................................... 35 3.6.3 Reference marks Added ............................................................................................ 36 3.7 Preserving Original Intentions. ...................................................................... 37 4 Results ............................................................................................................................ 39 4.1 Completing the model ........................................................................................ 39 4.2Dealing With Errors In The Cadastre ............................................................. 42 4.2.1Solutions ........................................................................................................................... 43 4.3The current DCDB ................................................................................................ 45 4.4 Quality Of The Least Squares Model .............................................................. 47 5 Conclusions ................................................................................................................... 49 Works Cited ...................................................................................................................... 51 Bibliography ..................................................................................................................... 52 Appendix 1 List of errors ............................................................................................. 55 Appendix 2 Referenced deposited Plans ................................................................ 58 Appendix 3 Full Map of Kogarah ............................................................................... 64 Coordinated Cadastre: Putting The Puzzle Back Together Jason Terry 5 Figure 1 DCDB Aerial Photography comparison Urban .................................................................. 11 Figure 2 DCDB comparison with Aerial Photography Rural .......................................................... 12 Figure 3 Landonline Survey Process ...................................................................................................... 14 Figure 4 Map of St George Parish ............................................................................................................ 24 Figure 5 Comparison of a house from 1943 -­‐ 2014 .......................................................................... 25 Figure 6 Aerial photography 2010 and 1943 ...................................................................................... 26 Figure 7 Old standard Deviations V New Standard Deviations from FIXIT 4 ........................... 30 Figure 8 Example of overlapping lines in least squares (Source: Ayres,2008) ....................... 38 Figure 9 Example of overlapping lines in least squares. (Source: Ayres, 2008) ..................... 38 Figure 10 Fixit 4 output showing change in coordinates ................................................................ 43 Figure 11 Comparison of results from different solutions ............................................................. 44 Figure 12 Picture of model overlayed DCDB ....................................................................................... 45 Figure 13 Comparison of completeness between DCDB and Model ............................................ 46 Figure 14 Main: DP236872 Insets: enlarged view of Occupation and distances from model and DCDB to Measured OCCupation ............................................................................................. 48 Table 1 New Zealand SADCDB Accuracy ............................................................................................... 13 Table 2 Hierarchy of Evidence ................................................................................................................. 16 Table 3 Population Statistics .................................................................................................................... 19 Table 4 Example of Standard deviations and observation data ................................................... 28 Table 5 Comparison of standard deviations ........................................................................................ 29 Table 6 Transformation Parameters ..................................................................................................... 37 Table 7 Variance Factor Progression of model .................................................................................. 41 Table 8 Changes of Standard deviation for different models ........................................................ 41 Table 9 Comparison of coordinates of selected point between Final Model DCDB ............... 47 Coordinated Cadastre: Putting The Puzzle Back Together Jason Terry 6 ABSTRACT In the Age of Global Navigation satellite system GNSS the coordinates will be established as the foundation of how future land rights are viewed and managed. Using the examples of New Zealand and Singapore, this project will look at what a coordinated cadastre can be and what realisation could be used in Australia. The data for this project was received from previous theses on this topic, 98 Deposited Plans (DPs) and a Fixit software input file. The Digital cadastral database was also supplied by Land and Property Information (LPI). The outcome of this project is an understanding of the needs and challenges the spatial industry will face in the near future, a realisation that the cadastre is not and will never be perfect, and the potential advantages of having a digital model of the Cadastre The Abstract could also have mentioned the Case Study and briefly
outlined the investigations undertaken and main results.
Coordinated Cadastre: Putting The Puzzle Back Together Jason Terry 7 1 INTRODUCTION 1.1 THE CADASTRE It is impossible to give a definition of a cadastre, which is both concise and comprehensive (Dowson and Sheppard, 1956; p.47), but Ian Williamson (1985) does try. “A cadastre is a complete and up-­‐to-­‐date official register or inventory of land parcels in any state or jurisdiction containing information about the parcels regarding ownership, valuation, location, area, land use and any buildings or structures thereon.” The Cadastre holds importance in not just land rights but in the planning, designing, interaction of sustainable development in the future. How the cadastre interacts with these roles depends on how the government and the spatial industry deal with pressures that guide sustainable development. The Australian Cadastre is made up of individual surveys of individual parcels for individual owners (Williamson, 1996). This current system of description titling works for the current uses and infrastructure established for this cadastral system. So why change something that works so well? The idea of integrating all survey plans is not a new one. Knibbs proposed a similar idea in 1891 in his paper, Trigonometrical, General and Cadastral Surveys. ‘‘The adoption of a comprehensive method of dealing with every class of survey, in such a way as to reduce them to a common basis, would secure a high degree of Coordinated Cadastre: Putting The Puzzle Back Together Jason Terry 8 certainty in regard to the positions of landed property…which being done they become integral parts of a great whole, instead of isolated or detached measurements” (Knibbs, 1891).
The current system holds up because each individual piece is separate from everything else, and will only interact with the rest of the cadastre when something changes. This allows errors and problems in the cadastre to hide and accumulate over time. Coordination may disrupt the current status of boundaries but it may also contribute to removing some errors and achieve a higher level of integrity. Putting the separate puzzle pieces of the cadastre together could achieve Knibbs’ (1891) visions of the cadastre as a great whole. 1.1.1 COORDINATED CADASTRE The coordinated cadastre is a broad idea where coordinates are implemented into property boundaries. This allows the location of any boundary to be accessible by coordinates, to a degree of accuracy with ease. There are different types of realisation of coordinated cadastre which all differ from country to country based on the legislation implemented by the governing bodies. “Cadastral Futures” (Bennett et al., 2010) outlines the potential future cadastral systems. They include Survey Accurate Cadastres, 3D/4D Cadastres, Real Time Cadastres, Global Cadastres, Object Orientated Cadastres and Organic Cadastres. The power given to the coordinate is dependent on the quality of the cadastre and the realisation of coordination required in the cadastre. These systems all stem from Coordinated Cadastre: Putting The Puzzle Back Together Jason Terry 9 the idea that a universal coordinated system will accurately integrate the cadastre to increase accuracy, integrity and usability. That’s not to say they will be perfect, each realisation will require an understanding of the original cadastre to effectively manage the needs of that country. 1.1.2 DCDB The Digital Cadastral Data Base (DCDB) is a digital representation of a cadastral map produced by the digitisation of cadastral plans. This task was performed to establish a visual correct cadastral map and a way to integrate infrastructure and services with the cadastral map. While the original plans were survey accurate the resulting database coordinates were estimated to be up to 2m out in urban areas and up to 50m out in rural areas, due mainly to the digitising process. With the increased use of GNSS the errors in the DCDB have become more noticeable in everyday use. This is evident in SIXmaps view where DCDB boundary lots are shown over aerial photography seen in Figure 1 and 2. With the use of Coordinates from GNSS systems and Aerial and satellite photography, the disconnect between reality and the digital world is becoming more obvious. Boundary surveys generally are very local and do not have to connect to the whole network, and this is evident in the accuracy of the DCDB as Ian Williamson (1996) explained, “The absolute accuracy of coordinates may vary by hundreds of metres although the relative accuracy of coordinates in a localised area may be much better”. Coordinated Cadastre: Putting The Puzzle Back Together Jason Terry 10 Figure 1 and 2 show the difference between the visible fence line and the coordinated DCDB boundaries. Obviously this is not a true representation of the accuracy of the DCDB, as the fence line is not the surveyed boundary line and the aerial photography is also not perfect, but it is an example of the disconnect between the digital world and the physical world. Figure 1 DCDB Aerial Photography comparison Urban Coordinated Cadastre: Putting The Puzzle Back Together Jason Terry 11 Figure 2 DCDB comparison with Aerial Photography Rural 1.2 SURVEY ACCURATE DCDB New Zealand has taken on this task with The Survey Conversion Project. Landonline was implemented to improve the accuracy of the digital cadastre and to achieve a survey accurate DCDB. The accuracies achieved were around 0.2m for urban areas and 0.5m for rural areas, shown in Table 1, and are orders of magnitude better than the original DCDB. The Survey Conversion Project entered parcel dimensions (bearings and distances) into the database to attempt to achieve this accuracy. About 70% of lots were entered, which accounts for only 10% of the surface area of New Zealand. The remaining 90% of New Zealand or 30% of the cadastre in rural areas is largely unchanged (LINZ, 2011) Coordinated Cadastre: Putting The Puzzle Back Together Jason Terry 12 “This work has been undertaken in three parts: the definition of a new datum to which the converted survey will be adjusted; the creation of a sufficient density of control in the conversion areas to gain a high degree of co-­‐ordinate accuracy; and the capture and adjustment of boundary and traverse data from current survey plans tied to the new control. The intent of the exercise is to create a network of a measured co-­‐ordinate accuracy standard that can be used by external surveyors and for electronic plan lodgement.” (Spaziani, 2002) The table below indicates the expected accuracy in survey accurate and non survey accurate areas. Table 1 New Zealand SADCDB Accuracy Accuracy status
Land use
95%
accuracy1
Landonline
accuracy order2
Survey-accurate
(bearings
and
distance captured from survey plans)
Urban
0.20
7
Rural
0.50
8
Urban
5
9 or 10
Rural3
20
10
Remote
rural3
100
11 or 12
Non survey-accurate (digitisation of
cadastral record maps)
(LINZ, 2011) The advantages for industries that use the DCDB are obvious; the increased accuracy provides a greater influence and power to the abilities of the DCDB and the GIS packages that use it. Coordinated Cadastre: Putting The Puzzle Back Together Jason Terry 13 How does this effect Surveyors? Figure 3 shows what The New Zealand Land Title service sees as the application of the survey accurate DCDB with surveyors. While not much has changed with the overall process, the changes are in the streamlining of data acquisition, field survey reconnaissance, and lodging of survey plans. “The survey points are downloaded into an electronic field book, GPS, or similar. The coordinates are used to accurately locate any old marks in the field. The survey is undertaken, new marks placed, etc. in relation to existing boundaries. Parcels are defined and areas calculated“ (Haanen et al., 2002).
Figure 3 Landonline Survey Process The Process described in Figure 3 shows that the surveying tasks are unaffected by the changes. Only the cadastral information and submissions are upgraded. Coordinated Cadastre: Putting The Puzzle Back Together Jason Terry 14 1.3 LEGAL COORDINATED CADASTRE A legal coordinated cadastre is explained as all property boundaries in a cadastre defined by coordinates guaranteed by the state (Andreasson, 2006) A legal coordinated cadastre has the implication of rewriting legislation to rewrite the procedures for retracement of boundary surveys. The current state of legislation in most Australian states and similar cadastral systems are based on the physical evidence left behind by the original survey. This is shown in the popular surveying saying “monuments before measurements”. The current survey regulations state: (1) If a surveyor makes a re-­‐survey, the surveyor must adopt the boundaries as originally marked on the ground as the true boundaries unless there is sufficient evidence to show that the marks have been incorrectly placed or have been disturbed. (Surveying Regulations; 2012 reg 19) S19 of the surveying Regulations 2012 outlines the procedure to adopt for the retracement survey and the hierarchy of evidence in Table 2 shows the order of relative importance of each type of evidence. Original intention is an important concept in boundary retracement and can be applied in different ways based on the evidence found on plan and in the field. Coordinated Cadastre: Putting The Puzzle Back Together Jason Terry 15 Table 2 Hierarchy of Evidence 1. Natural features 2. Original crown marking of grant boundaries 3. Monuments 4. Original undisturbed marking of private surveys 5. Occupations 6. Measurements (Surveyor General Direction No.7, 2004) The original intention of a survey can be shown by the bearings and distances printed on the plan. These values are the intentions of the survey based on the calculations; straight roads were meant to be straight and property dimensions were designed to fit. This can also be shown on the ground as well as monuments and natural features such as walls and rivers. The application of original intention is in the actual marking of these original boundaries. These boundaries “as originally marked on the ground” are stated by the regulations as the “True Boundaries”. These original marks are placed by surveyors with an intention based on the original plan, but mistakes happen, and measurement or transcription error can occur creating a disconnect between plan and ground boundaries. ‘It is not the job or responsibility of ... [reinstating] surveyors to correct the originals. It is their job to report any discrepancies found’ (Brown et al. 1995, p. 32).
Coordinated Cadastre: Putting The Puzzle Back Together Jason Terry 16 In coordinating a cadastre a decision has to be made to trust the plan as the original intention as it would be near impossible to reconstruct the cadastre by resurveying all the boundaries because it would be very resource and labour intensive. Hallman’s (2000) states that when “a local survey had been connected to two or more points on the geodetic network, a permanent record of the local survey was thereby established” This would allow the remarking of these boundary lines if all original marks were gone “but it rests upon the assumptions that all angular and linear measurements of the survey were absolutely correct, assumptions that would not go unchallenged in court” (Hallman 2000, 4-­‐61).
The only way to efficiently and effectively produce a cadastral model that is legally defined is to accept the plan dimensions and provide provisions in legislation for the capture and manipulation of errors found between plans and their ground marks. Singapore has implemented such provisions in their Boundaries and Survey Mapping Act (2004) s12 & s13 CORRECTION OF MAP PART III SURVEY MAP S12. (1) ALL MAPS PUBLISHED UNDER THE REPEALED ACT SHALL CONTINUE TO BE VALID UNTIL THEY HAVE BEEN DECLARED TO BE SUPERSEDED UNDER SECTION 7(F). (2) NO MAP WHETHER PUBLISHED UNDER THE REPEALED ACT OR GENERATED FROM THE CO-­‐ORDINATED CADASTRE SHALL BE CORRECTED, ALTERED OR ADDED TO IN RESPECT OF ANY BOUNDARY OF ANY LAND THEREIN LAID DOWN, EXCEPT IN THE FOLLOWING CASES: (A) WHERE IT IS FOUND THAT A MAP DOES NOT CORRECTLY REPRESENT THE BOUNDARIES OF ANY LAND, THE CHIEF SURVEYOR SHALL INQUIRE INTO THE REASON Coordinated Cadastre: Putting The Puzzle Back Together Jason Terry 17 FOR THE DIFFERENCE AND, IF IT IS FOUND TO BE DUE TO INACCURACY IN THE SURVEY CAUSED BY ERROR IN MEASURING THE ANGLES OR THE SIDES OF THE LAND…HE SHALL GIVE NOTICE TO THE OWNERS OF THE LAND AFFECTED OF THE ERROR Map to be conclusive evidence s13. (2) Upon a declaration under section 7(f), every map generated from
the co-ordinated cadastre shall be conclusive evidence in all courts of
the boundaries of the land comprised in every land shown therein,
subject only to any order made under section 12 for their modification,
correction or alteration. (Surveying and Mapping Act, 2004) These provisions for errors in the coordinated cadastre show that surveyors will still play a vital role in the continual management of the cadastre although with some caveats. “The liability of errors deriving from cadastral surveys is, as before, tied to the registered surveyor who performed the survey in question, according to BSMA Section 11D(5). Boundary data in the coordinated cadastre is not, therefore, contrary to registered titles – guaranteed by the Singapore State” (Andreasson, 2006). This is where the Singapore scenario starts to differ, Singapore is 100 and 1000 times smaller then Sydney and NSW in size respectively, making it 100 and 1000 times more densely populated than Sydney and NSW respectively. This has an affect on the decision to create a coordinated cadastre. “The very high development density and great number of multi-­‐dwelling blocks, makes boundary issues perhaps less controversial than would be the case in sparsely populated areas. Somewhat simplified: Once the buildings are raised, few people bother about the exact position of the legal boundaries” (Andreasson, 2006). Coordinated Cadastre: Putting The Puzzle Back Together Jason Terry 18 Table 3 Population Statistics Region Area (km2) People Population density pop/km2 Singapore 716 5.3million 7,400 Sydney 12,415 4.5million 360 NSW 809,444 7.4million 9 1.4 3D CADASTRES A 3D cadastre is a cadastre with the added height dimension. With the innovation of land use forced by the pressures of urbanisation many structures are not easily represented in a 2D Cadastre, like underground infrastructure, tunnels, pipes, multi storey structures, bridges and roadways. Not only the physical world would be represented in a 3D cadastre but also the rights, restrictions and responsibilities associated on the land would be represented as separate objects in the cadastre. The goal is to make these rights, restrictions and responsibilities easier to understand for the general public. Traditional 2D cadastres do solve some of these problems by using height in the cadastre, with having upper and lower limits of the feature, e.g. parcel boundaries in stratum subdivision and easements. So in a sense this does represent a 3D cadastre, but the complication comes when this information needs to be accessed. Limited information is shown on cadastral maps or DCDB’s that represents these 3 Coordinated Cadastre: Putting The Puzzle Back Together Jason Terry 19 dimensional traits, this information is hidden on 2 dimensional plans for only the surveyors and lawyers to find. While this information is ultimately the responsibility of the lawyers and surveyors this information can be very useful in the planning and development of individual property owners and the easy access to this information will benefit both private property owners and the professionals that use it. To this date 3D cadastres, in their fullest, are still just an idea, no country has implemented a working 3D cadastre. 2 CHALLENGES FOR CREATING THE DIGITAL CADASTRE 2.1THE DATA ENTRY PROCESS The data entry process is a time consuming and mind boggling process, the amount of errors found in this data set shows the attention to detail required for an individual to take when inputting large data sets. A lot of time was spent sifting through the data looking between DP’s and data file, converting between feet and metres. Upgrading the Current Paper plan system to a digital system is paramount in the future of the Cadastre. The advantage of having a plan that can be read digitally allows it to be checked for consistency within itself but also of the surrounding Cadastre. At present this is not possible with the quality of the DCDB in NSW. With an improvement of the DCDB a check with the consistency can improve the quality of the cadastre or at least Coordinated Cadastre: Putting The Puzzle Back Together Jason Terry 20 maintain the quality for the future. New Zealand has established this system with the upgrade of their DCDB to a Survey accurate DCDB using Plan bearings and distances from survey plans. This improved observations allows the DCDB to be used in more accurate processes and allows New Zealand to maintain their cadastre even with the Uncertainty of Earthquakes. 2.1.1 CROWD SOURCING Cadastre 2034 outlines the importance of crowdsourcing in developing the future cadastre, a good source of cheap labour that, when broken down into smaller task, requires little training. I.P Willaimson (1996) States that it could cost somewhere between 15-­‐85 dollars per lot to enter DP information into a Data set while Elfick (1995) states it could cost $6 per lot, with the data entry process costing less than $2 per lot. With the help of thousands/millions of individuals in the crowd sourcing community this can be cut down, the only challenge would be to break the whole task into smaller bits. An application that walks someone, with limited knowledge of the spatial industry, through the steps needed to read the information, enter and check the data. While quality cannot be assured, the simple task can be easily checked for mistakes. As well as a way to tag the boundary corners as unique points, and a way to import this data into a model to adjust the information. This idea is a potential further progression of this thesis, to replicate the model completed in this thesis using an application to crowd source data. The other advantage of this application would be the potential of a teaching and advertising tool. Learning how to look at a plan, read the information and draw the lot and check that it closes properly, teaches some of the basics of the industry and if the application could be Coordinated Cadastre: Putting The Puzzle Back Together Jason Terry 21 used in a crowdsourcing sense could broaden the understanding outside the spatial industry. 2.1.2 LANDXML LandXML is a file format that is “an international standard for exchanging geospatial information” (Icsm, 2011) allowing hard information to be used and analysed digitally. Land XML has been implemented by the LPI in NSW for ongoing testing and will in the near future become compulsory as the submission type for deposited plans. LandXML is planned to “provide a more efficient digital environment” (NSW Department of Lands, 2007). “The program will substantially enhance the quality of plan data, reduce requisitions and improve plan processing and turnaround times”. The ability of LandXML to be read digitally enables checking of plans for gross errors to be automated, and make requisitions more consistent and uniform. The quick turnarounds of plan processing will stream line the connectivity between the surveyed land to the digital cadastre. Now this doesn’t do all that much to the DCDB in NSW. With the addition of connections to state survey marks in the 1990’s, little has changed for the DCDB. These state survey mark connection are used to coordinate boundary corners and are added to the DCDB to improve the quality of the database. This is an attempt to improve the quality of the DCDB but this technique would take over 300 years (Gardner & Strong 2010) to cover the whole 4million lot cadastre. So the faster implementation of coordinated lots will no better improve the DCDB than State survey mark connections did since the 1990’s. A much faster system would be for Coordinated Cadastre: Putting The Puzzle Back Together Jason Terry 22 one similar to that of the implementation of Torrens Title from old system Title. Where every dealing in property is required to have a redefinition survey in LandXML performed, to allow Survey accurate Cadastral coordinates to be introduced in the DCDB at a much faster rate. It would mean more work for surveyors and it would only take 150 years as it did for Old System title to be… nearly removed as a titling system. 2.2 OLD SYSTEM TITLE Old system title is the remanent titling system established for colonial Australia. The system relied on a physical deed to prove ownership, metes and bounds description of the land. So very little information of who owned what land was kept which made proving title very difficult and so was not guaranteed by the state. It was replaced in the 1850’s by the Torrens title system, which required a central register of title and a plan of survey for every dealing in land. Today there is still old system land present in NSW and will prove to be a challenge if any upgrade would occur to the NSW Cadastre. With old system title and. monuments hold very high stature because of the nature of metes and bounds Descriptions 3 HURSTVILLE CASE STUDY Coordinated Cadastre: Putting The Puzzle Back Together Jason Terry 23 The case study is of a number of subdivisions in Hurstville located within King George’s Road, Hillcrest Avenue and Wonoira Road, containing approx. 250 lots. The land was originally subdivided between 1907 and 1952 with several more recent subdivisions and road widening’s. Figure 4 Map of St George Parish 3.1 A BRIEF HISTORY The Hurstville area was mainly dairy farmland until 1884 when the Railway was extended to Hurstville. Land was quickly subdivided to accommodate the increase interest in property. With quick easy access to the city many rich professionals chose to build Large Villas in the area. With the addition of the Hurstville steam Brick Co opening also in 1884, many of the homes in the area today are grand double brick Villas still standing strong. (Hurstville City Council, n.d.) See Appendix 3 for full size Hurstville council map Coordinated Cadastre: Putting The Puzzle Back Together Jason Terry 24 Figure 5 Comparison of a house from 1943 -­‐ 2014 With the rapid expansion of Hurstville the roads and subdivisions were expanded with little foresight into the future of the area. Belmore road was still a Dead end dirt road in 1932. As the area grew Belmore Road became a main access road to the southern suburbs of Sydney. With the expansion of the road it was upgraded to a main arterial road and renamed King Georges Road. In 1968 a road widening was designed to upgrade the road to accommodate the increase traffic through the area. 3.2 THE CASE STUDY John Toson’s (1994) Thesis “Combining Cadastral Survey Data” originally chose the site. The data file used for this case study is from Michael Ayres (2008) Thesis “Cadastral Modelling” who spent 40+ hours entering the data in the least squares 25 Coordinated Cadastre: Putting The Puzzle Back Together Jason Terry format used, called FIXIT. Finally additional editing and error checking was performed by Pat Smith (2012) “Coordinated Cadastre: A Case Study” Figure 6 Aerial photography 2010 and 1943 3.2.1 THE SITE The site is the amalgamation of 10 large subdivisions, starting with DP5040 in 1907 and ending with DP28243 in 1952. Since 1952 there have been 7 two-­‐lot subdivisions, and some road widenings. The resulting cadastre is a convoluted collection of lots that were squeezed in to fit where they could. 3.3 THE DATA SET The data set received is in a format compatible with the least squares product Fixit 4. It was originally put into this format by Mitchell Ayres in 2008 thesis cadastral modelling and subsequently edited and manipulated by Patrick Smith’s (2012) thesis Coordinated Cadastre: Putting The Puzzle Back Together Jason Terry 26 to improve the information and use the model to find some reliability in the coordinates. Least squares has been the standard for modelling and manipulating data sets in surveying for many years. The justification of its use has been outlined many times in previous theses and in the application in the industry. 3.3.1 FIXIT 4 Fixit 4 is the latest edition of the least squares program designed by Bruce Harvey, the supervisor for this thesis. This program has been used for the past theses for this topic. This program was selected again for this thesis because of the format of the data received and also due to the timesaving factor of having the author, who is very familiar with this program, close at hand. This data set is based on plan bearing data set, which uses observations between two points as a defined line and uses the group bearing of each individual plan or sets of plans to adjust theses observations onto a single azimuth. The plan bearing adjustment and the observations are adjusted using least squares principles. 3.3.2 VARIANCE FACTOR AND STANDARD DEVIATIONS The variance factor is a relationship between the expected accuracy of the data set and the accuracy of the data set. A variance factor of < 1 infers that the accuracy of the data set is greater than the expected accuracy, or better than expected. A variance factor of > 1 infers that the accuracy of the data set is worse than the Coordinated Cadastre: Putting The Puzzle Back Together Jason Terry 27 expected accuracy, or worse than expected. A variance factor much larger than 1, infers a problem in the data set. The expected accuracy of the data set is set by the standard deviation of the observations. This is implemented by a global standard deviation, and over ridden by standard deviations on individual observations, if applied. In Table 4 observations 4-­‐
5 will use the assigned Standard deviations while observations 1-­‐2 will use the global standard deviations. Table 4 Example of Standard deviations and observation data Global STDEV Observation type PBG PBG HDIS HDIS Dist mm 15 Dist ppm 15 Dir " 30 Dir cent 0 From To observation STDEV 4 1 4 1 5 2 5 2 119.3040 135.0800 137.845 19.845 10 12 The given data set had a high global standard deviation, many very high individual standard deviations, and a variance factor of 1. So the accuracy was as expected, but the expectations were very low, thus concluding the data set was not very reliable. To establish how reliable the data was and what needed to be changed, the very high individual standard deviations were removed and the global standard deviations were revised. The revised global standard deviations were based on the equation from P.B. Jones (1985), ‘Statistics for Civil Engineers and Surveyors’. Coordinated Cadastre: Putting The Puzzle Back Together Jason Terry 28 σ2=a2/12 σ=a/√ 12
Where a = to the round off error The global standard deviations were set to the lowest quality observations. These were the oldest plans. Bearings were recorded to the nearest 60 seconds and the shortest distances were recorded to the nearest ¼ inch or 6mm. While the round off error for bearings, at 60 seconds, is reasonable for the technology of the day, the 6mm for distance is well beyond the accuracy expected by steel band measurements, especially considering the steep terrain of the area. The surveying regulations for distance measurements requires that “both the accuracy of the calibration and the field measuring technique is to be such that any length measurement made with the equipment will achieve an accuracy of 10mm + 15ppm” (as per the Surveyor General Directions 2006 Measuring). These regulations are for modern day EDM measurements and such the expectation is that steel band measurements would be of similar or slightly lower accuracy of what is expected today. An estimate of 15mm and 15ppm was used for the older distance measurements. Distance (mm) Distance (ppm) Directions (sec) Centring Original Model 60 20 60 20 Final Model 15 18 0 15 Table 5 Comparison of standard deviations Coordinated Cadastre: Putting The Puzzle Back Together Jason Terry 29 The separate generation of deposited plans (DP) showed consistent difference in round off and accuracy regulations. As such weightings for each generation of measurements would be assigned a separate weighting. The majority of the observations entered into the data set were the original subdivisions in the earliest era, and as such, use the global standard deviations. The only plans to end up with individual weightings where the more recent subdivisions done between 1980 and present time. They were given an accuracy of 10” for angle and 10mm for horizontal distance Once the global standard deviations were lowered from the unrealistically low expectations the variance factor increased significantly and the problems in the data set were shown. The variance factor rose from 1 to over 200 and the outliers creased significantly as seen in Figure 7. Figure 7 Old standard Deviations V New Standard Deviations from FIXIT 4 Coordinated Cadastre: Putting The Puzzle Back Together Jason Terry 30 3.3.3 OUTLIERS Outliers are observations that are adjusted by the least squares program, by an amount greater than the amount that is allowed by standard deviation set for the observation So by changing the standard deviation you are not changing the outcome of the program but more so moving the bar of what is acceptable. Saying that, down weighting an observation, by largely increasing the standard deviation, does change the outcome by allowing it to move more and putting more weight on the other observations around it. This can help with the investigation to see where the problems are in the network but not necessarily fix the problem. This is what occurred in the original model. 3.4 PROBLEMS IN THE MODEL With the revised standard deviations, the number of outliers increased significantly. Using the principles of least squares an investigation is launched into the possible sources of the problems in the cadastre. The goal of this investigation was to asses whether or not the problems in the data set were data entry errors or errors in the cadastre. The large majority of the outliers came down to data entry errors. Checking for these errors was a time consuming process and the amount of data entry errors was larger than expected. Using the outliers as guides to where problems existed, sifting through 1800 observations for “typos” is like finding a needle in a haystack, but to have any real idea of the quality of the cadastre in the area these had to be found. Coordinated Cadastre: Putting The Puzzle Back Together Jason Terry 31 A number of the errors in the data set revolved around the road widening along Wonoira road. This road widening changes cross street connections and how lots actually connected. The majority of the errors resulted from miss calculations, “dyslexic moments”, and just plain recording errors. Considering the large amount of data, the conversion process from feet to metres from old illegible plans, the previous authors can be forgiven for the errors, especially if they manage to survive the process with there sanity. See Appendix 1 for a full list of errors found 3.4.1 CADASTRAL DISCREPANCIES Once all the data entry errors were dealt with the problems that remained were discrepancies in cadastral information found between different deposited plans. One of these discrepancies was found by Toson in his 1994 thesis, a distance of 0.36m was found between DP5040 and DP9192 with measurements of 162.870m and 162.510m respectively. The discrepancy between the two plans moves the point at which the boundary bends. DP9192 was adopted because it kept the shape of the lots in DP 9192, and only changed the boundary corner of lot 12, in DP 5040, by 1mm as the bend is only 9’. Based on this evidence, this was accepted by the author as a solution to the problem. See appendix 2 for referenced DP’s Another resulted from the subdivisions of part lot 16 DP9192, in DP381958. The part lot was subdivided and appeared to connect to an existing boundary corner. The error in the measurements proved to create a new point 460mm past the corner. In this model based on the evidence found the author chose to create the extra point Coordinated Cadastre: Putting The Puzzle Back Together Jason Terry 32 to fit with the measurements rather then assume the intention of the surveyor to connect to the existing boundary corner. See appendix 2 for referenced DP’s Another discrepancy was found at the bend in the road on Obrien Road. In DP957489, because of the poor quality of the subdivision plan, the west and east lot boundaries appear and are assumed to be parallel, with equal distances for the southern and northern boundaries to suggest this, but after searching the surrounding DPs, DP18644 and DP309273 it appeared not to quite fit the area. The western boundary appeared to have a difference of about 2’ in angle. When this was adjusted it did not solve the problem in the model as the outlier remained. It was becoming very complicated and further investigation was required but limited time caused this mystery to be unresolved, for now. See Appendix 2 for referenced DP’s 3.5 RECENT DP’S There are a number of recent DP’s completed within the last couple of decades that have not completely been entered into the model. State survey mark connection observations from boundary corners were used to establish azimuth around the site collected mainly from these DP’s. However the lot dimensions were not previously added into the data set to avoid overlapping information with the older subdivisions. Once entered into the data set, the new plans created outliers in the model. These discrepancies are differences in the definition of the boundaries from the old or original subdivision to the recent one. Coordinated Cadastre: Putting The Puzzle Back Together Jason Terry 33 A discrepancy in the cadastre is why a registered surveyor gets paid. When a difference is found a decision is made using the expertise, experience and training the surveyor has received. Thus creating a scenario that is fair and justified based on the evidence collected. In saying this each survey will be done differently, and will achieve a different result. Unfortunately as time goes by, the evidence available for each survey is reduced, and the evidence in the immediate area is limited, so boundary definitions are less accurate than that of original subdivisions, despite having more precise measuring equipment. The original Standard deviations were set at 10” for bearing and 10mm for distances Based on the regulations for boundary surveys in NSW, unfortunately they didn’t fit with the model and needed to be adjusted. There are a number of ways to address the problems. One is to adjust the standard deviations on all the observations so that the problems work them selves out, to create an average of the error in the cadastre. The other is to leave the observations out and take the original survey as the correct boundary. The technique chosen was to down weight the recent DPs observation slightly so to be more consistent with the original subdivisions, but so the recent DPs still have some influence on the model. The new standard deviations for these plans were 30” for bearing 30mm for distance. These plans were still important to the Model because of the connections from State survey marks to boundary corners. These connections help orientate and connect the model to the MGA coordinate system. To ensure that the coordinates achieved by these state survey mark connections are sound, some reference marks could be found to help strengthen the quality of the model. Coordinated Cadastre: Putting The Puzzle Back Together Jason Terry 34 3.6ADDITIONAL INFORMATION 3.6.1REFERENCE M ARKS Reference marks are an integral part of the definition of a property boundary, with them the integrity of the boundary fix is vastly improved. Having a model of only plan bearings and distances it is essentially defining boundaries with the lowest form of evidence in the hierarchy of evidence. So it makes sense to include reference marks into a least squares model of the cadastre. The more recent DP’s reference marks were more likely to exist than the older reference marks, especially considering the road widenings and path and kerb replacements so this would be a good starting point to search for reference marks. Also along King Georges Road there is a proposed Road widening with lines of concrete blocks and other reference marks, marking the change in bearing of the road. The majority of these marks were not expected to be found but if luck would allow it one would be found. 3.6.2 THE FIELD SURVEY The field survey was planned to use GNSS RTK this was chosen based mainly on ease, Total station could have been used unfortunately time required for this technique was not suitable for this project. While trees could cause difficulties in locating marks with GNSS, techniques can be used to get around poor sky view. No control needed to be set up and could have been done with one person. To improve accuracy, marks were located as they were found, and again, sometime later, on the way back. This should have eliminated any possible bias in the satellite constellation. Coordinated Cadastre: Putting The Puzzle Back Together Jason Terry 35 The majority of the more recent DP’s reference marks were found in good sky views for RTK GNSS. The search for the road widening reference marks along Kings Georges Road was unsuccessful. Due to the road widening the properties along king Georges road have been slowly bought back by the government, abandoned or demolished. The majority of these marks were inaccessible with the GNSS; they fell in abandoned housing or overgrown vacant lots. A number of marks inside Arrowsmith park at the corner of King Georges road and Wonoira road were believed to have been there, but unfortunately were unable to be uncovered. An occupation was located using the GNSS on the corner of Hillcrest Ave and King Georges Road. The location was a difficult The corner of brick was referenced In DP236872 Sheet 4 of 4 as 4¾” or 120mm clear of the boundary. This point was not possible to be entered into the least squares model, as there was no direct connection to the boundary. This occupation was then used to check the model. The offset to the original model was 1.2m. The occupation in comparison to the original model shows the problems within the data set. This helped to isolate some of the issues and locate further errors in the data set. Once adjusted the square offset measured was 100mm clear of the boundary, at 20mm , an acceptable difference 3.6.3 REFERENCE M ARKS ADDED The thesis that originally used this Case study, Toson 1994, did locate one of the marks that were unable to be uncovered by this author. Toson’s survey incorporated this mark into the control and a least squares adjustment. The Coordinates of this point were in ISG so a transformation was needed. Luckily several State survey marks were used in both Thesis’ and a relatively easy transformation was achieved. Coordinated Cadastre: Putting The Puzzle Back Together Jason Terry 36 Transformation parameters ISG MGA Shift Point E N E N ΔE SSM80832 309300.044 1239832.149 324628.764 6239679.619 15328.720 point 8 308758.487 1240026.581 324083.505 6239863.451 Swing 1°07’05” scale factor 1.00002 Check Between Adjusted and SCIMS Coordinates Adjsuted coordinates Scims Coordinates ΔE SSM80831 324416.693 6239978.031 324416.697 6239978.026 -­‐0.004 SSM88564 324510.405 6239590.13 324510.404 6239590.143 0.001 ΔN 4999847.470 ΔN 0.005 -­‐0.013 Table 6 Transformation Parameters The coordinates for this mark were put into Fixit and connection observations to the model were added to the data file. This additional information fit well with the existing model. There were 4 reference marks located from the recent DP’s. 1 each from DP1021964 and DP 1140180, and 2 from DP 846011. These reference marks were scattered across the site bringing some extra strength into parts of the model that weren’t as well anchored. The reference mark connections were added and fit nicely with the existing model 3.7 PRESERVING ORIGINAL INTENTIONS. Preserving the original intention of a cadastral survey is important when modelling the cadastre. To fully represent the cadastre the intentions of the survey are needed to be implemented in the survey. Coordinated Cadastre: Putting The Puzzle Back Together Jason Terry 37 In Ayres (2008) thesis, techniques for maintaining straight lines were discussed when modelling a cadastre. These techniques were used to stop unwanted bends and overlaps in what were intended to be straight lines. This is a very important concept as it strengthens Figure 8 Example of overlapping lines in least squares (Source: Ayres,2008) The cadastre, as well as maintaining the intention of the original survey. This technique involved adding Angles observations of 180° for 3 points that are intended to be straight lines. Adding small standard deviations for these observations would allow a rigid format to allow straight lines to proper gate. Initial standard deviation for the angle observations was set at 5mm; this relatively small standard deviation would only allow small variations over short lines. While these observations stopped any overlap in the cadastre, it allowed too much movement in the model for these lines, still allowing the straight lines to wobble, so the standard deviation needed to be set lower to force the lines to stay straight. So a standard deviation of 0.1mm was applied. This forced the lines to stay straight, with no movement at all Coordinated Cadastre: Putting The Puzzle Back Together Jason Terry 38 4 RESULTS 4.1 COMPLETING THE MODEL The final Cadastral model was substantially better than the initial Data set. With the addition of New weightings, straight line angles, and with around 30 errors found and fixed in the data set the max shift from the original coordinates was about 2m. The resulting variance factor went from 253 to become 1.14 and the final data set had an average 95% confidence interval of 30mm where the original data set had 400mm. This variance factor was as good as what was expected, at 1.14. However the group variance factor showed some room for improvement. While Horizontal distance was 0.75 and angle was at 1.1 but Bearing was over 2.2. Some changes could still be made to change the quality of the model. The first step was to change the Angle Standard deviation, with a STDEV of 5” this allowed the lines to move around too much and negated the main reasons they were in the model, which was to maintain straight lines. This was fixed by giving them a standard deviation of 0.1”, which forced the model to maintain straight lines. this changed the group variance factor from 1.07 to 0.1 and none of these angles were adjusted to fit the model. The second step involved the Recent DP observations. These observations didn’t completely fit with the existing model and caused outliers to appear. Since these observations were redundant observations they were not required to shape the model. Despite their increased precision in measuring techniques of recent years Coordinated Cadastre: Putting The Puzzle Back Together Jason Terry 39 they were not as accurate as the underlying subdivisions. So to represent this the observations were down weighted from 10” and 10mm to 30” and 30mm. this improved the group variance factors for bearing from 2.7 to 2.4 and distance from 1.06 to 0.87. Small improvements in the quality but because of the small number of recent DPs this was what was expected. The final step was to update the bearing variance factor from 2.4. The model at this stage showed some remaining outliers of the model. From here the decision was made to increase the global standard deviation of the plan bearings to 30”. This increase in standard deviation was used to improve consistency with the adjustment, while it didn’t solve any of these outliers it allowed the model to average out the discrepancies that still existed. With the new Standard deviations the final variance factor reduced to 1.01, with group variance factors of 1.14, 0, and 0.87 for bearing, angles and distances respectively. The final standard deviations were representative of the model. The new standard deviation, while fitting well with the resulting model, didn’t help explain the remaining minor outliers in the cadastre. While the obvious discrepancies in the cadastre were found, the minor discrepancies are a lot harder to find and rectify. To achieve an unwavering confidence in a coordinated cadastre all these discrepancies should be found, assessed and either fixed or accepted into the model. Unfortunately this is so complicated that fixing the minor errors will affect adjacent lots, creating other minor errors and will continually be an unsolved problem. With boundary marking errors, calculations errors, and accumulated round Coordinated Cadastre: Putting The Puzzle Back Together Jason Terry 40 off errors, with all the errors in the cadastre, each subdivision can never be replicated to its original intentions. Table 7 Variance Factor Progression of model Model Update Original new STDEV errors removed RM's Added Angles Added Angles with new STDEV New DP's added New DP's with Higher STDEV Final Model cadastral error added VF Total 0.77 253.27 1.14 1.29 1.25 1.31 1.57 1.34 0.86 1.01 Bearing Angles HD 0.91 0.72 205.17 259.3 5.16 0.75 5.6 0.86 2.17 1.07 0.86 2.29 0.01 0.87 2.65 0.01 1.06 2.35 0.01 0.87 1.07 0 0.87 1.14 0 0.95 Table 8 Changes of Standard deviation for different models Model Update Original new STDEV errors removed RM's Added Angles Added Angles with new STDEV Std dev Bearing 60" +20mm 18" +0mm 18" +0mm 18" +0mm 18" +0mm 18" +0mm Angles 5" 0.1" HD 60mm + 20ppm 15mm+ 15ppm 15mm+ 15ppm 15mm+ 15ppm 15mm+ 15ppm 15mm+ 15ppm New DP's added New DP's with Higher STDEV Final Model cadastral error added 18" +0mm 18" +0mm 0.1" 0.1" 15mm+ 15ppm 15mm+ 15ppm individual weights for new dp's 10mm 10" 30mm 30" 30" +0mm 30" +0mm 0.1" 0.1" 15mm+ 15ppm 15mm+ 15ppm 30mm 30mm 30" 30" Coordinated Cadastre: Putting The Puzzle Back Together Jason Terry 41 4.2DEALING WITH ERRORS IN THE CADASTRE The existence of errors in the cadastre is a reality. How a cadastral system deals with these errors, will depend on the country and the people involved in the process. Understanding how the modelling system deals with these errors will guide the decisions made to accommodate for any errors that arise. To compare what happens to the coordinates, when cadastral discrepancies are present in the model, one of the discrepancies found and solved for was reintroduced into the data set. The discrepancy is between points 348 and 392, two separate plans differ in length between these point by approx. 350mm. In the model, the solution was to accept the longer length and adjust the shorter observations to fit. When the error was reintroduce into the model it resulted in a shift of about 110mm along the line for point 348 and 170mm along the line for point 390 See figure 11. The expectation is for the least squares to average out the error and give it a best-­‐case scenario, and it did just that but the other side effect of reintroducing the error was the movement of the surrounding points. Not only did the least squares adjust the erroneous points but it adjusted all the points around it by, on average, over 50mm this can be seen in Figure 10 Coordinated Cadastre: Putting The Puzzle Back Together Jason Terry 42 Figure 10 Fixit 4 output showing change in coordinates The black lines represent the shift in coordinates before and after the error was reintroduced into the model. The Least squares averages out the error through the model to achieve a best-­‐fit solution. While the shift appears uniform in one direction along the boundary line, the shift actually effects different points in opposite direction, shuffling its way though the model. This comparison shows the unpredictable nature of least squares and the propagation that occurs when an error is present in the cadastre. 4.2.1SOLUTIONS There are usually a number of ways to achieve a solution that doesn’t affect the whole of the surrounding cadastre. The solution, for the above example, was chosen to minimise any changes to adjacent lots, but it is not the only solution in this problem. The other solution was to hold the shorter distance fixed and adjust the northern boundary connected to point 348. The expected result would be for the Coordinated Cadastre: Putting The Puzzle Back Together Jason Terry 43 model to adjust point 348 only and keep the surrounding marks unchanged. When this solution was added to the model this is close to what happened. Point 348 moved by 320mm along the line of the boundary while 392 moved 5mm. The average shift in coordinates for the surrounding points was under 10mm. This shows the either one of these changes to the model is a solution to the discrepancy in the cadastre. The solution in the real world will depend on the surveyor. Figure 11 Comparison of results from different solutions Coordinated Cadastre: Putting The Puzzle Back Together Jason Terry 44 4.3THE CURRENT DCDB Figure 12 Picture of model overlayed DCDB The current DCDB is in a state of mediocrity, for the current uses of the DCDB it is adequate but has very limited ability to be repurposed for any other, more sophisticated tasks. The accuracy of points, in the DCDB, are largely unknown and the connections between lots are not always correct, mainly caused by the digitising method that collected the data. Updated coordinates, changed from survey information, are made with little regard for the users, especially in rural areas. Land and Property Information (LPI) provided the current DCDB in this area. The DCDB, in figure 13, shows the techniques of digitising blocks to form the basis of the database. Coordinated Cadastre: Putting The Puzzle Back Together Jason Terry 45 This shows the limitations that are inherent in the DCDB with the information that has been left behind on the deposited plans that were digitised. The expected accuracy for an urban area in the DCDB is around 1-­‐2m. As expected many points in the DCDB are in the range of 1-­‐2m but many are also in a range below 0.5m. The range in difference from the Least squares model shows the unknown quality of the boundary points in the DCDB. As shown in table 9. Figure 13 Comparison of completeness between DCDB and Model Coordinated Cadastre: Putting The Puzzle Back Together Jason Terry 46 Model DCDB Pt no. E N E N 1 324009.1135 6240029.008 324009.138 6240029.237 72 324084.7599 6239849.137 324085.461 6239849.094 534 324217.0567 6239669.483 324217.676 6239669.762 479 324284.8131 6239577.511 324285.428 6239577.304 407 324613.2694 6239691.92 324613.685 6239692.161 511 324507.7964 6239847.073 324506.634 6239846.379 185 324414.1686 6239962.188 324415.091 6239962.010 307 324146.9908 6239929.081 324147.702 6239928.708 417 324325.0562 6239728.453 324326.061 6239728.947 349 324426.1459 6239659.479 324427.054 6239659.275 150 324320.2793 6239872.323 324321.194 6239872.104 370 324348.5469 6239490.977 324349.262 6239491.060 Average Δ STDEV ΔE ΔN -­‐0.024 -­‐0.229 -­‐0.701 0.043 -­‐0.619 -­‐0.279 -­‐0.615 0.207 -­‐0.416 -­‐0.241 1.162 0.694 -­‐0.922 0.178 -­‐0.711 0.373 -­‐1.005 -­‐0.494 -­‐0.908 0.204 -­‐0.915 0.219 -­‐0.715 -­‐0.083 0.387 0.263 0.571 0.316 Table 9 Comparison of coordinates of selected point between Final Model DCDB 4.4 QUALITY OF THE LEAST SQUARES MODEL These Comparisons are not very useful unless we have some understanding of how good the model is. So how close are we to the true cadastre? The 95% confidence interval for the model was 30mm for both easting and northing and New Zealand’s survey accurate DCDB, for urban areas, was quoted at within 200mm for the 95% confidence interval. A rough estimate for this model is somewhere between 30mm– 200mm. The Reference marks that were collected and added into the model around the site helped to strengthen the model, but also confirmed that the model was connecting to the real world. The addition of the reference marks only shifted the boundary corners they referenced by 5mm-­‐30mm. Coordinated Cadastre: Putting The Puzzle Back Together Jason Terry 47 One bit of defining evidence we collected in the field survey, to connect the model to the real world, was the occupation on the corner of Hillcrest Avenue and King Georges Road. This occupation was on DP236872, sheet 4 of the proposed road widening for King Georges Road. This offset was measured at 4¾” or 120mm clear of the boundary. With the updated model in place the occupation was measured from the model at 100mm clear of the boundary. While the DCDB measured at 540mm over the boundary. 43/4” = 0.120m Figure 14 Main: DP236872 Insets: enlarged view of Occupation and distances from model and DCDB to Measured OCCupation Coordinated Cadastre: Putting The Puzzle Back Together Jason Terry 48 5 CONCLUSIONS To have an unwavering confidence in a coordinated cadastre, which one should have if the coordinates are the legal definition of the cadastre, minor discrepancies will have to be fully solved to avoid litigation over land ownership. Unfortunately no amount of resurvey or calculations will ever perfectly recalculate the cadastre from its original subdivisions. At some point in the calculations a decision would have to be made to say this is going to be the new boundary, and that it is now the legal definition of these properties and accept that it will not perfectly fit the original Cadastre. The other alternative is use those not quite perfect coordinates to guide the future shape of the cadastre, and aid the cadastral surveyor in their job by creating a survey accurate DCDB. With Registered surveyor’s numbers on the decline and the spatial industry on the rise, the cadastre has to improve to keep up with the current age of access. Any increase in the efficiency is something to strive for A full coordinated cadastre in NSW seems far and distant, and with the complexity and size of the NSW Cadastre, proves to be a great challenge. The existing examples of a legal coordinated cadastre, Singapore, Northern Territory and ACT, are all less than one tenth the size of NSW in population and/or area. Scaling up becomes a totally new challenge. With New Zealand’s success in achieving a Survey accurate DCDB, the approach of using coordinates as an aid, rather than the definition, for determining boundaries appears to be the sensible approach. Coordinated Cadastre: Putting The Puzzle Back Together Jason Terry 49 A measured approach that improves and makes the cadastre more accessible is the goal. To create an accurate model of the cadastre incorporating the collective knowledge of deposited plans, including reference marks and occupations is vital to the process. Having a digital representation of the information that is hidden in deposited plans is a time saver that is worth pursuing for the future of Surveying. As time wears the remaining cadastral evidence, being able to access the cadastre as whole, not only the adjacent lots, to define a boundary will restore a greater integrity into the future cadastre. The challenge now is to pull all the pieces together and put the cadastral puzzle back together. Coordinated Cadastre: Putting The Puzzle Back Together Jason Terry 50 WORKS CITED Andreasson, K., 2006. Legal Coordinated Cadastres – Theoretical Concepts and the Case of Singapore. Munich: FIG FIG. Ayres, M., 2008. 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FIG Conference 2010 Facing the Challenges- Building the
Williamson, I. and L. Holstien (1977). "Aspects of Title Surveys in Australia."
Coordinated Cadastre: Putting The Puzzle Back Together Jason Terry 54 APPENDIX 1 LIST OF ERRORS PBG 81 1001 1 48 30 00 H DIS 81 1001 5.486 PBG 1001 1002 1 96 06 40 H DIS 1001 1002 16.510 PBG 300 1002 1 48 30 00 H DIS 300 1002 3.353 com measurements added for point 1001 to fix error associated to corner PBG 141 124 2 161 19 00 H DIS 141 124 12.192 PT 141 CHANGED FROM 139 A TRANSCRIPTION ERROR IN POINT CONNECTION PBG 511 427 18 152 49 02 H DIS 511 427 11.503 CROSS STREET CONNECTION WAS NOT CLEAR CLACULATIONS HAD TO BE MADE USING CAD TO DETERMINE THE TRUE VALUE BASED ON THE CLOSE OF THE ADJACENT BOUNDARIES COMPBG 457 349 17 133 27 00 COMH DIS 457 349 20.149 NO IDEA WHERE THIS CAME FROM THE BEND IN THE ROAD HAS CAUSED SOME CONFUSION NEW PBG AND DISTANCE ADDED BELOW PBG 457 349 17 133 02 14 H DIS 457 349 20.120 this is the connection actual bends are not perpendicular to road bearing probably half ANGLE PBG 83 79 1 274 51 30. H DIS 83 79 19.812 TRANSCRIPTION ERROR 18.812 CHANGED TO 19.812 PBG 80 84 1 271 57 45. H DIS 80 84 42.516 PBG 80-­‐84 271 37 45 changed to 271 57 45 a transcription error it was a very poorly written bearing PBG 129 130 2 230 38 00. H DIS 129 130 18.065 129 -­‐130 CHANGE FROM 230 00 00 -­‐ 230 38 00 JUSTR INPUT ERROR PBG 146 147 2 283 12 00. Coordinated Cadastre: Putting The Puzzle Back Together Jason Terry 55 H DIS 146 147 9.66 hd 10.18 CHANGED TO 9.66 ARC DISTANCE ENTERED INSTEAD OF CHORD DISTANCE PBG 76 74 3 315 08 00. H DIS 76 74 12.19 cHANGE 195 TO 74 BECAUSE THEY ARE THE SAME POINT PBG 206 207 4 45 04 00. H DIS 206 207 62.675 206 -­‐207 CALCULATED AS 62.675 NOT 62.87 CALCULATION OR READING ERROR OF CONVERSION TABLE PBG 317 1000 2 50 11 00. H DIS 317 1000 1.530 measurments added for point 1000 to fix road widening error PBG 354 353 10 44 19 00. H DIS 354 353 16.091 PBG 352 355 10 224 19 00. H DIS 352 355 16.091 THESE DISTANCE ARE WRONG THIS WAS THE ONLY ONE IN THE LOTS THAT CHANGED CHANGED FROM 18.288 16.091 JUST WRONG PBG 392 390 11 224 20 16. H DIS 392 390 15.24 ADDED AS join between corners of lot to keep shape PBG 403 405 11 44 34 00. H DIS 403 405 15.24 PBG 405 537 11 314 40 00. H DIS 405 537 45.635 change 45.599 to 45.635 PROBLEM BETWEEN 405-­‐537 405-­‐406=1.5 406-­‐537=44.075 BUT 405-­‐406-­‐537=/= 45.575 PBG 407 406 12 233 03 20. H DIS 407 406 60.17 407-­‐406 232 03 20 change to 233 03 20 transcription error dp and other observations entered show 232 as entry error PBG 424 425 13 134 44 45. H DIS 424 425 25.133 distance changed from 25.188 to 25.133 reading error of hard to read plans PBG 426 424 13 134 44 45. Coordinated Cadastre: Putting The Puzzle Back Together Jason Terry 56 H DIS 426 424 15.735 hdist for 426 424 not found added PBG 444 445 14 221 45 00 H DIS 444 445 17.329 was 20.377 transcription error (56' read as 66' conversion table table confirms that it is 56') PBG 451 450 7 49 30 15 H DIS 451 450 19.711 OBS 451 -­‐ 450 CHANGED TO 19.711 FROM 19.66 CONVERSION FROM dp PBG 461 462 7 134 59 00 H DIS 461 462 38.329 HD CHANGE FROM 40.879 TO 38.329 DUE TO DP TRANSLATION ERROR DISTANCE TO CORRECT CORNER NOT CLEARLY DEFINED Coordinated Cadastre: Putting The Puzzle Back Together Jason Terry 57 APPENDIX 2 REFERENCED DEPOSITED PLANS DP 5040 DP9192 Coordinated Cadastre: Putting The Puzzle Back Together Jason Terry 58 DP381958 Coordinated Cadastre: Putting The Puzzle Back Together Jason Terry 59 DP957489 Coordinated Cadastre: Putting The Puzzle Back Together Jason Terry 60 DP1021964 Coordinated Cadastre: Putting The Puzzle Back Together Jason Terry 61 DP 1140180 Coordinated Cadastre: Putting The Puzzle Back Together Jason Terry 62 DP 846011 Coordinated Cadastre: Putting The Puzzle Back Together Jason Terry 63 APPENDIX 3 FULL MAP OF KOGARAH Coordinated Cadastre: Putting The Puzzle Back Together Jason Terry 64