5.0 Geodetic Monumentation
5.1 Subject Discussion
A network of widely-spaced, permanent monuments serves as the basis for computing
lengths, distances and apparent angular relationships between relative positions. In the
past, ground-based theodolites, tapes, and electronic devices were the primary geodetic
field measurements used. Today, the technological expansion of the Global Positioning
System has made it possible to perform extremely accurate geodetic surveys at a fraction
of the former cost.
In order to ensure the accuracy of land record systems as well as natural resource,
communication, transportation, and other mapping projects; it is essential to have a
consistent coordinate system. The National Spatial Reference System (NSRS), managed
by the National Geodetic Survey (NGS), is the standard in defining the latitude,
longitude, elevation, scale, gravity, and orientation of control points throughout the
United States. Both state and local governments have producers that generate geodetic
control data for smaller-scale needs.
Since 1985, Horizontal Geodetic control has almost exclusively been established through
the use of GPS. GPS is based on resection using distances derived mathematically from
signals transmitted between a constellation of space vehicles operated by the US
Department of Defense and ground-based receivers and base stations operated by
surveyors and agencies. No matter which measuring system is employed, geodetic
control is established in a hierarchical manner. More densely spaced points are
established by starting from a most precise, but rather sparse, network of points. This
method is generally less precise but sufficient to meet most specific user needsi.
The various requirements for geodetic control demand different levels of positional
accuracy. Traditionally, geodetic control is categorized as primary, secondary, or
supplemental. Primary or First Order control is used to establish geodetic points and to
determine the size, shape, and movements of the earth. Secondary or Second Order, Class
I control is used for network densification in urban areas and for precise engineering
projects. Supplemental or Second Order, Class II and Third Order control is typically
used for network densification in non-urban areas and for surveying and mapping
projectsii.
Accuracy for the Geodetic Monumentation data layer needs to be disclosed; and the
individual analyzing the shared data needs to be able to verify that the data accuracy is
appropriate for the announced need.
5.1.1 Accuracy Standards for Geodetic Control
The absolute positions of points can never be exactly known since all measurements
contain some error. Instead, we usually speak of relative accuracy and the relationships
between points. NSRS is based upon a hierarchical classification of accuracy whereby
new geodetic control is referenced to previously existing control of a higher order. The
accuracy of a geodetic control point is determined by the accuracy of the survey and the
quality of the adjustmentiii.
Horizontal Accuracy
Prior to GPS, surveys designed to achieve first-order positions were performed by very
few agencies or private firms using very expensive surveying equipment. These agencies
and firms would require significant training and education in geodesy and least squares
adjustment theory. By 1985, GPS could easily outperform first-order horizontal accuracy,
and was becoming increasingly more affordable and accessible to the average surveyor.
To accommodate the improved positional capability of GPS, new standards for horizontal
data were submitted for adoption to the Federal Geodetic Control Committeeiv. A- and Borders of accuracy specify horizontal positional tolerances of 5 mm + 1:10,000,000 of the
observed base line, and 8 mm + 1:1,000,000 of the observed base line, respectively.
Stations with A- and B- order accuracy are commonly called High Accuracy Reference
Network (HARN) Stations.
There is no vertical accuracy implied by A- or B-orderv. Many standards exist for
geodetic control, depending on the type of survey work to be accomplished and the
methods to be used. The Federal Geodetic Control Subcommittee (FGCS) is responsible
for developing the standards and specifications used in the NSRS, the nation's primary
control network. The FGCS has developed standards for horizontal and vertical control
work, both by conventional and GPS surveying methods, as well as standards for gravity
surveys, baseline calibration, and other activitiesvi.
Continuously Operating Reference Stations (CORS)
The Continuously Operating Reference Station (CORS) network coordinated by the
NGS, is a group of GPS reference stations which provide code range and carrier phase
data to users in support of post-processing of GPS data for more accurate and reliable
results and control.
The GPS data at CORS stations is recorded at a 30, 15, 5 or 1 second sampling rate in the
Receiver Independent Exchange Format Version 2.10 (RINEX-2) formatvii. Since Feb. 9,
1994 (the first site was NIST), the data sets have been available free of charge and can be
retrieved over the Internet at cors.ngs.noaa.gov or via the World Wide Web at
http://www.ngs.noaa.gov/CORS/.
The data are also archived on CD ROM and can be purchased or be downloaded by FTP
from ftp://cors.ngs.noaa.gov/.
Currently, the National Geodetic Survey provides data from over 390 sites.
Beginning in December 1994, the U.S. Coast Guard (USCG) began installing a
Differential GPS (DGPS) network along the U.S. coasts for maritime navigation. The
network includes the Atlantic, Pacific, and Gulf coasts, the Great Lakes, southern Alaska,
Hawaii, and Puerto Rico.
By agreement, NGS utilizes data from these stations as part of the NGS CORS network
and will make the data available for post-processing applications. Additional stations will
be added as federal and local agencies and private concerns feel the need to establish base
stations. For those new sites that are established near existing CORS sites, check the
Cooperative CORS Web page at http://www.ngs.noaa.gov/CORS/Coop.viii
CORS datasheets take a similar form to that of regular NGS datasheets; however, a
number of additional sets of data elements are available for each CORS station point,
such as data availability, RINEX downloads, notices, and so on, as shown in the
following screenshot:
5.1.2 Development of Geodetic Control
Geodetic control surveys are usually performed to establish a basic control network
(framework) from which supplemental surveying and mapping work is performed.
Geodetic network surveys are distinguished by use of redundant, interconnected,
permanently monumented control points that comprise the framework for the NSRS or
are often incorporated into the NSRSix.
These surveys must be performed to far more rigorous accuracy and quality assurance
standards than those for control surveys for general engineering, construction, or small
scale topographic mapping purposesx. This process of submitting data to the NGS for
inclusion in the NSRS is generally referred to as “Bluebooking”.
Geodetic network surveys to be included in NSRS must be performed to meet automated
data recording, submittal, project review, and least squares adjustment requirements
established by NGS xi. These standards form an effective basis for data sharing between
other organizations maintaining geodetic control.
Most geodetic surveying activities begin from a monumented station in NSRS, which is
developed and managed by NGS.
In Pennsylvania, the most active producer of geodetic control is the Pennsylvania
Department of Transportation (PENNDOT).
Geodetic control stations are substantially monumented so that they will be both stable
and durable. To support precise positioning, monuments must be stable and protected,
minimizing movement due to frost, soil conditions, crustal motion, and human
disturbance. To be of value in a control network, monuments must be durable and
recoverable for future use.
5.1.3 Standards for Geodetic Data in the National Geodetic Survey Database
NGS defines and manages the NSRS - the framework for latitude, longitude, height,
scale, gravity, orientation and shoreline throughout the United States. NSRS provides the
foundation for transportation, communication, and defense systems, boundary and
property surveys, land records systems, mapping and charting, and a multitude of
scientific and engineering applicationsxii. Point position information from the NSRS data
base is distributed as Data Sheets.
A typical NGS Data Sheet is shown below (partial sample)xiii:
1
National Geodetic Survey,
Retrieval Date = APRIL 6, 2005
MA1767 ***********************************************************************
MA1767 CBN
- This is a Cooperative Base Network Control Station.
MA1767 DESIGNATION - V 404
MA1767 PID
- MA1767
MA1767 STATE/COUNTY- PA/BUTLER
MA1767 USGS QUAD
- PARKER (1979)
MA1767
MA1767
*CURRENT SURVEY CONTROL
MA1767 ___________________________________________________________________
MA1767* NAD 83(1992)- 41 01 00.04285(N)
079 43 01.76995(W)
ADJUSTED
MA1767* NAVD 88
357.344 (meters)
1172.39
(feet) ADJUSTED
MA1767 ___________________________________________________________________
MA1767 X
860,338.634 (meters)
COMP
MA1767 Y
- -4,742,209.911 (meters)
COMP
MA1767 Z
4,164,033.496 (meters)
COMP
MA1767 LAPLACE CORR1.95 (seconds)
DEFLEC99
MA1767 ELLIP HEIGHT323.92 (meters)
(03/28/01) GPS OBS
MA1767 GEOID HEIGHT-33.45 (meters)
GEOID03
MA1767 DYNAMIC HT 357.171 (meters)
1171.82 (feet) COMP
MA1767 MODELED GRAV980,130.4
(mgal)
NAVD 88
MA1767
MA1767 HORZ ORDER - A
MA1767 VERT ORDER - FIRST
CLASS II
MA1767 ELLP ORDER - THIRD
CLASS II
MA1767
MA1767.The horizontal coordinates were established by GPS observations
MA1767.and adjusted by the National Geodetic Survey in March 2001.
MA1767
MA1767.The orthometric height was determined by differential leveling
MA1767.and adjusted by the National Geodetic Survey in June 1991.
MA1767
MA1767.The X, Y, and Z were computed from the position and the ellipsoidal ht.
MA1767
MA1767.The Laplace correction was computed from DEFLEC99 derived deflections.
MA1767
MA1767.The ellipsoidal height was determined by GPS observations
MA1767.and is referenced to NAD 83.
MA1767
MA1767.The geoid height was determined by GEOID03.
MA1767
MA1767.The dynamic height is computed by dividing the NAVD 88
MA1767.geopotential number by the normal gravity value computed on the
MA1767.Geodetic Reference System of 1980 (GRS 80) ellipsoid at 45
MA1767.degrees latitude (g = 980.6199 gals.).
MA1767
MA1767.The modeled gravity was interpolated from observed gravity values.
MA1767
MA1767;
North
East
Units Scale Factor Converg.
MA1767;SPC PA S
188,759.392
434,546.818
MT 1.00000824
-1 16 34.6
MA1767;UTM 17
- 4,541,401.082
607,863.016
MT 0.99974319
+0 50 31.1
MA1767
MA1767!
- Elev Factor x Scale Factor =
Combined Factor
MA1767!SPC PA S
0.99994919 x
1.00000824 =
0.99995743
MA1767!UTM 17
0.99994919 x
0.99974319 =
0.99969240
MA1767
MA1767
SUPERSEDED SURVEY CONTROL
MA1767
MA1767 NAVD 88 (03/28/01) 357.34
(m)
1172.4
(f) LEVELING
3
MA1767 NGVD 29 (06/03/92) 357.515 (m)
1172.95
(f) ADJUSTED
1 2
MA1767
MA1767.Superseded values are not recommended for survey control.
MA1767.NGS no longer adjusts projects to the NAD 27 or NGVD 29 datums.
MA1767.See file dsdata.txt to determine how the superseded data were derived.
MA1767
MA1767_U.S. NATIONAL GRID SPATIAL ADDRESS: 17TPF0786341401(NAD 83)
MA1767_MARKER: I = METAL ROD
MA1767_SETTING: 49 = STAINLESS STEEL ROD W/O SLEEVE (10 FT.+)
MA1767_SP_SET: STAINLESS STEEL ROD
MA1767_STAMPING: V 404 1982
MA1767_MARK LOGO: NGS
MA1767_PROJECTION: FLUSH
MA1767_MAGNETIC: N = NO MAGNETIC MATERIAL
MA1767_STABILITY: B = PROBABLY HOLD POSITION/ELEVATION WELL
MA1767_SATELLITE: THE SITE LOCATION WAS REPORTED AS SUITABLE FOR
MA1767+SATELLITE: SATELLITE OBSERVATIONS - March 02, 2004
MA1767_ROD/PIPE-DEPTH: 6.80 meters
MA1767_SLEEVE-DEPTH : 3.0 meters
MA1767
MA1767 HISTORY
- Date
Condition
Report By
MA1767 HISTORY
- 1982
MONUMENTED
NGS
MA1767 HISTORY
- 20000410 GOOD
PADT
MA1767 HISTORY
- 20030905 GOOD
TERRSV
MA1767 HISTORY
- 20040302 GOOD
PADT
MA1767
MA1767
STATION DESCRIPTION
A typical NGS CORS Data Sheet is shown below (partial sample)xiv:
AF9631 ***********************************************************************
AF9631 HT_MOD
- This is a Height Modernization Survey Station.
AF9631 CORS
- This is a GPS Continuously Operating Reference Station.
AF9631 DESIGNATION - WILKES BARRE CORS ARP
AF9631 CORS_ID
- WIL1
AF9631 PID
- AF9631
AF9631 STATE/COUNTY- PA/LUZERNE
AF9631 USGS QUAD
- HARVEYS LAKE (1983)
AF9631
AF9631
*CURRENT SURVEY CONTROL
AF9631 ___________________________________________________________________
AF9631* NAD 83(CORS)- 41 18 18.91349(N)
076 00 55.10100(W)
ADJUSTED
AF9631* NAVD 88
417.39
(meters)
1369.4
(feet) GPS OBS
AF9631 ___________________________________________________________________
AF9631 EPOCH DATE 2002.00
AF9631 X
1,159,635.777 (meters)
COMP
AF9631 Y
- -4,656,343.785 (meters)
COMP
AF9631 Z
4,188,203.445 (meters)
COMP
AF9631 ELLIP HEIGHT385.66 (meters)
(03/??/02) GPS OBS
AF9631 GEOID HEIGHT-31.71 (meters)
GEOID03
AF9631
AF9631 HORZ ORDER - SPECIAL (CORS)
AF9631 ELLP ORDER - SPECIAL (CORS)
AF9631
AF9631.ITRF positions are available for this station.
AF9631.The coordinates were established by GPS observations
AF9631.and adjusted by the National Geodetic Survey in March 2002.
AF9631.The coordinates are valid at the epoch date displayed above.
AF9631.The epoch date for horizontal control is a decimal equivalence
AF9631.of Year/Month/Day.
AF9631
AF9631.The orthometric height was determined by GPS observations and a
AF9631.high-resolution geoid model using precise GPS observation and
AF9631.processing techniques.
AF9631
AF9631.The PID for the CORS L1 Phase Center is AC8019.
AF9631
AF9631.The XYZ, and position/ellipsoidal ht. are equivalent.
AF9631
AF9631.The ellipsoidal height was determined by GPS observations
AF9631.and is referenced to NAD 83.
AF9631
AF9631.The geoid height was determined by GEOID03.
AF9631
AF9631;
North
East
Units Scale Factor Converg.
AF9631;SPC PA N
127,898.938
745,257.686
MT 0.99995875
+1 08 51.2
AF9631
AF9631!
- Elev Factor x Scale Factor =
Combined Factor
AF9631!SPC PA N
0.99993951 x
0.99995875 =
0.99989826
AF9631
AF9631
SUPERSEDED SURVEY CONTROL
AF9631
AF9631 NAD 83(CORS)- 41 18 18.91365(N)
076 00 55.10151(W) AD(1997.00) c
AF9631 ELLIP H (01/??/01) 385.65
(m)
GP(1997.00) c c
AF9631 NAD 83(CORS)- 41 18 18.91351(N)
076 00 55.10107(W) AD(1996.00) c
AF9631 NAD 83(CORS)- 41 18 18.91351(N)
076 00 55.10107(W) AD(1997.00) c
AF9631 ELLIP H (04/??/97) 385.69
(m)
GP(1997.00) c c
AF9631 ELLIP H (04/??/97) 385.69
(m)
GP(1996.00) c c
AF9631
AF9631.Superseded values are not recommended for survey control.
AF9631.NGS no longer adjusts projects to the NAD 27 or NGVD 29 datums.
AF9631.See file dsdata.txt to determine how the superseded data were derived.
AF9631
AF9631_U.S. NATIONAL GRID SPATIAL ADDRESS: 18TVL1500673141(NAD 83)
AF9631_MARKER: STATION IS THE ANTENNA REFERENCE POINT OF THE GPS ANTENNA
AF9631
AF9631
STATION DESCRIPTION
AF9631
AF9631'DESCRIBED BY NATIONAL GEODETIC SURVEY 2002
AF9631'STATION IS A GPS CORS. LATEST INFORMATION INCLUDING POSITIONS AND
AF9631'VELOCITIES ARE AVAILABLE IN THE COORDINATE AND LOG FILES ACCESSIBLE
AF9631'BY ANONYMOUS FTP OR THE WORLDWIDE WEB.
AF9631'
FTP CORS.NGS.NOAA.GOV: CORS/COORD AND CORS/STATION_LOG
AF9631'
HTTP://WWW.NGS.NOAA.GOV UNDER PRODUCTS AND SERVICES.
Most municipal mapping projects that require an orthophoto base utilize an adjusted
control network for photogrammetric data processing. It is recommended that the entire
network, or at least a functional subset of it, be permanently monumented to preserve
these points for future reference. This network of control will provide convenient ties for
local surveyors to establish geodetic coordinates for their local projects. This will serve
the local community in developing a consistent base for region wide mapping and the
ability to tie into a statewide coordinate system, PA SPCS, as defined in the Pennsylvania
Statutes, 68 P.S. §955xv.
5.1.4 Geodetic Data available from PENNDOT
In June 2003, PENNDOT unveiled an online resource which provides access to
information about their geodetic control network. The primary purpose of this resource,
called the Photogrammetry Asset Management System (PAMS), is to provide a webbased GIS application for the management of mapping, photogrammetry, survey control
points and other records for the Photogrammetry Division of PENNDOTxvi. The
application is available online at http://www.penndotpams.org.
The PAMS site, based on UMN MapServer 3.6.6xvii, allows graphically navigating and
selecting on the Survey Control layer via the web-based mapping application to query
against a database containing geodetic control info consisting of a number of data
elements, as well as datasheets as .pdf files- the datasheets contain diagrams locating the
monuments.
The PAMS geodetic monumentation data fields and some typical values are shown
below:
Benchmark Code
Station
Established By
NGS PID
Latitude
Longitude
Elevation meters
Elevation feet
Horizontal Datum
Horizontal Adjustment
Vertical Datum
Horizontal Order
Vertical Order
Monument Type
Project SR
County
PennDOT District
Monument Condition
Last Survey
Comments
2400
G078
PennDOT
40 14 51.06225
76 48 41.83270
127.476
418.23
NAD83
1992
NAVD88
First
Third
Disk in Concrete Inlet
0083-034
Dauphin
8-5
Good
2002
A typical PAMS datasheet is shown belowxviii:
5.2 Use Cases
Photogrammetric Control:
Use of existing geodetic control monuments or establishing new geodetic control
monuments (primarily PENNDOT, either through a contractor or by PENNDOT
resources) for photogrammetric mapping control
Engineering Control:
Use of existing geodetic control monuments or establishing new geodetic control
monuments (Primarily PENNDOT and other large construction projects) for engineering
project control.
Cadastral Mapping:
Use of existing geodetic control monuments to tie parcel boundaries to PA State Plane
Coordinate System of 1983xix
5.3 Recommendations
5.3.1 PGDSS Version 1.0 Recommendation (Existing)
Geodetic control should include the following items:
Name
Length
Type
Lat
8 digit numeric
The latitude of the monument in decimal degrees.
Long
8 digit numeric
The longitude of the monument in decimal degrees.
Name
35 character
Name of monument.
Owner
25 character
Agency who placed and/or maintains the monument.
Order
15 character
Accuracy level of monument.
Description
50 character
Description of monument. Stone pile, pin, etc.
Additional elements should be included (although representation is not specified in
PGDSS Version 1.0):
1) The Coordinate system used; Pa State Plane North or South, UTM, Etc
2) Horizontal Datum; NAD83 (1986), NAD83(1992), NAD83(NSRS) etc.
3) Geoid used for the calculations GEOID99, GEOID03 etc.
4) Coordinate listing of the Base Points and/or Monuments that were used such
as existing HARN Points or newly determined by OPUS, CORS, (which
CORS Stations used) etc.
5) Vertical Datum; NGVD 29, NAVD 88 or other.
6) Whether adjustment was constrained or not.
7) If multiple baselines were used for the location of all points.
8) Project accuracy requirements: Short summary on field procedures,
including make of receiver, antenna (fixed height or measureup), time of
day, and information on number of satellites monitored and any other
important data on field procedures such as were monuments set, type and
location, (Permanent or not). Location diagram and any ties should be
available for recovery purposes.
9) Summary of office procedures; Software brand and version used. Was
Corpscon, Nadcon, Vertcon or any mathematically shifted data utilized and
held as control and where?
10) Summary of the final accuracy of both the horizontal and vertical points,
including expected accuracy
11) Name of the firm doing the work, address, phone no., e-mail address,
contact person should be included. Also, any field collected data files, final
data files, loop closures, statistics, summaries, exclusions, etc, could be
included for future reference
5.3.2 PGDSS Version 2.0 Recommendation (Recommended)
The recommendations of Version 1.0 should be expanded for concurrence with
NGS/GOS model and applications. Currently, GOS provides a link back to NGS for
query and retrieval of geodetic monumentation in a number of formats, including ESRI
Shapefile. The shapefile format includes a number of data attributes which should be
examined for incorporation into PGDSS standards:
A crosswalk of PGDSS Version 1.0 and NGS Version 3.0 maps the following existing
elements to NGS/GOS elements:
PGDSS 1.0
Name
Lat
Long
Name
Owner
Horizontal
Order
Description
Corresponding NGS/GOS field
Length
Type
Latitude
(part of
GCD_HorizontalCoordinates class)
Longitude
(part of
GCD_HorizontalCoordinates class)
unique_ID
(part of GCD_Point class)
(implemented in metadata)
12 digit
DOUBLE
The latitude of the monument
in decimal degrees.
12 digit
DOUBLE
The longitude of the
monument in decimal degrees.
35 character
STRING
25 character
STRING
15 character
STRING
50 character
STRING
Name of monument.
(implemented in GCD_Accuracy
class)
descriptive_ID
(part of GCD_Point class)
Agency who placed and/or
maintains the monument.
Accuracy level of monument.
Description of monument.
Aluminum disc, et cetera
Additional elements recommended for inclusion are:
PGDSS 2.0
Name
Vertical Order
Horizontal
Datum
Vertical
Datum
Corresponding NGS/GOS field
Length
Type
(implemented in GCD_Accuracy
class)
(implemented in GCD_Datum
class)
(implemented in GCD_Datum
class)
15 character
STRING
STRING
Accuracy level of
monument.
Horizontal Datum of
monument
Vertical Datum of
monument.
STRING
Additional elements and refinements are anticipated in future versions. One typically
ubiquitous aspect of geodetic control databases surveyed is that they typically incorporate
elements of feature-level metadata to describe the points being collected.
NOAA Manual NOS NGS 5 “State Plane Coordinate System of 1983”xx provides two
sets of mapping equations for conversion between geodetic and SPCS 83 coordinates
(φ,λ) →(N,E) for Lambert projection as used in Pennsylvania, one optimized for
automated methods (polynomial coefficients) and the other for traditional methods. The
method of polynomial coefficients is intended for use with 10 significant digits. NGS
Manual No. 5 further recommends the use of at least 12 significant digits in conventional
computations in order to attain reliable millimeter-level accuracy. It is recommended that
the 8-digit specification be expanded to accommodate this level of accuracy. The FLOAT
type generally only supports 6 significant digits in most implementations of programming
languages, however DOUBLE typically provides 15 significant digits.
The NGS specification also provides the following UML diagram of the relationship of
data elements and their respective classes.
GCD_Point
+unique_ID : String
+unique_IDAssigner : String
+descriptiveID : String
+coordinates : GCD_Coordinates
GCD_Coordinates
+horizontal : GCD_HorizontalCoordinates
+vertical : GCD_VerticalCoordinates
GCD_HorizontalCoordinates
GCD_VerticalCoordinates
+latitude : Double
+longitude : Double
+accuracy : GCD_Accuracy
+geodeticDatum : GCD_Datum
-orthometricHeight : Double
-ellipsoidHeight : Double
-accuracy : GCD_Accuracy
-geodeticDatum : GCD_Datum
GCD_Accuracy
GCD_Datum
+local : Double
+network : Double
+baseDatum : String
+datumTag : String
+epochDate : String
Some additional suggested additions/revisions from the submitted comments
included:
o
o
o
o
o
o
Digital Photo of Monument
Directions for locating monument in the field
FGCS Classifications of Accuracy Order
Horizontal Adjustment
Follow NGS Data sheet standard
Conversion of OPUS results
These should be considered in future versions
5.4 Responsibilities
In Pennsylvania, the primary source and steward of geodetic data and monuments
remains NGS at the federal level. At the state level, PENNDOT is one of the primary
creators and maintainers of geodetic control networks.
Based on the 12/18/2003 PaMAGIC meeting and subsequent discussion, stewards
identified were:
Layer
Notes
State Steward
Road Centerlines
Buildings
Parcels
Orthophotos
Elevation
Geodetic
Monumentation
Hydrography
Includes addresses
Includes addresses
Includes addresses
PENNDOT
DCNR
DCNR
Digital PAMAP Program Office
DCNR/USGS
NGS/PAMAP Program Office,
PENNDOT
DEP
Political
Boundaries
Names
Transportation
County geometry, USGS/DEP
attributes
County/local where available
GNIS
Air, rail, other
Local
Steward
PENNDOT
USGS
PENNDOT
5.5 Definitions
At the time of compilation, there were not any thesauri found for consistent keywords,
usage and indexing of geodetic Monumentation data. Such a thesaurus and associated
definitions may already exist at NGS or with other organizations. Geodetic
Monumentation does typically encompass a narrow realm when it comes to data
generators, it is, however rich with technical terminology, procedures and other
descriptive terms. At some point in the future, it may be necessary to compile a thesaurus
and definitions of terminology.
5.4 References
Some additional references that provided background to this document:
1. Wisconsin State Cartographer's Office, Date Unknown. Producers of Geodetic
Control http://www.geography.wisc.edu/sco/geodetic/producers.html
2. Wisconsin State Cartographer's Office, Date Unknown. Geodetic Monuments
http://www.geography.wisc.edu/sco/geodetic/producers.html
Numerically Referenced End Notes:
i
State Mapping Advisory Committee (SMAC) of South Carolina., DRAFT: Geodetic
Control Standards For South Carolina
http://www.scgs.state.sc.us/smac/Geodetic%20Control%20Standards.htm
ii
Wisconsin State Cartographer's Office, Date Unknown. Accuracy Standards for
Geodetic Control
http://www.geography.wisc.edu/sco/geodetic/accuracy.html
iii
Wisconsin State Cartographer's Office, Date Unknown. Accuracy Standards for
Geodetic Control
http://www.geography.wisc.edu/sco/geodetic/accuracy.html
iv
Federal Geodetic Control Committee, 1989b, Geometric Geodetic Accuracy
Standards and Specifications for Using GPS Relative Positioning Techniques, version 5.0, reprinted with
corrections August 1, 1989.
v
Doyle, D., DEVELOPMENT OF THE NATIONAL SPATIAL REFERENCE SYSTEM
http://www.ngs.noaa.gov/PUBS_LIB/develop_NSRS.html
vi
Federal Geodetic Control Committee, Standards and Sepcifications for Geodetic Control Networks,
September 1984.
vii
NGS CORS Website:
http://www.ngs.noaa.gov/CORS/instructions2/
viii
NGS CORS Website:
http://www.ngs.noaa.gov/CORS/instructions1/
ix
Federal Geographic Data Committee, 1998, Geospatial Positioning Accuracy
Standards Part2: Standards for Geodetic Networks. FGDC-STD-007.2-1998
http://www.fgdc.gov/standards/documents/standards/accuracy/chapter2.pdf
x
Federal Geographic Data Committee, 1998, Geospatial Positioning Accuracy
Standards Part2: Standards for Geodetic Networks. FGDC-STD-007.2-1998
http://www.fgdc.gov/standards/documents/standards/accuracy/chapter2.pdf
xi
Federal Geographic Data Committee, 1998, Geospatial Positioning Accuracy
Standards Part2: Standards for Geodetic Networks. FGDC-STD-007.2-1998
http://www.fgdc.gov/standards/documents/standards/accuracy/chapter2.pdf
xii
National Geodetic Survey, Date Unknown. National Geodetic Survey: Who We Are
http://www.ngs.noaa.gov/INFO/WhoWeAre.html
xiii
Search and retrieval of NGS Data Sheets, shapefiles, and other data are available from the NGS website,
found at http://www.ngs.noaa.gov/cgi-bin/datasheet.prl
xiv
Search and retrieval of NGS Data Sheets, shapefiles, and other data are available from the NGS website,
found at http://www.ngs.noaa.gov/cgi-bin/datasheet.prl
xv
Purdon’s Pennsylvania Statutes, Title 68 § 956
Coordinate system defined
For purposes of more precisely defining the Pennsylvania Coordinate System, the following
definition by the National Ocean Survey/National Geodetic Survey (formerly the United States
Coast and Geodetic Survey) is adopted:
The Pennsylvania Coordinate System of 1927, North Zone, consists of a Lambert conformal
projection of the Clarke spheroid of 1866, having a central meridian 77 degrees 45 minutes west
of Greenwich. The intersecting cone of this projection cuts the surface of the spheroid in parallels
of latitude 40 degrees 53 minutes and 41 ; degrees 57 minutes north of the equator, along which
parallels the scale shall be exact. The origin of coordinates for this zone is at the intersection of
the meridian 77 degrees 45 minutes west longitude and the parallel 40 degrees 10 minutes north
latitude. This origin is given the coordinates x= =2,000,000 feet; y= =0 feet.
The Pennsylvania Coordinate System of 1927, South Zone, consists of a Lambert conformal
projection of the Clarke spheroid of 1866, having a central meridian 77 degrees 45 minutes west
of Greenwich. The intersecting cone of this projection cuts the surface of spheroid in parallels of
latitude 39 degrees 56 minutes and degrees 58 minutes north of the equator, along which parallels
the scale shall be exact. The origin of coordinates for this zone is at the intersection of the
meridian 77 degrees 45 minutes west longitude and the parallel 39 degrees 20 minutes north
latitude. This origin is given the coordinates x= =2,000,000 feet; y= =0 feet.
The Pennsylvania Coordinate System of 1983, North Zone, consists of a Lambert conformal
projection of the North American datum of 1983, having a central meridian of 77 degrees 45
minutes west. The northern standard parallel is latitude 41 degrees 57 minutes and the southern
standard parallel is latitude 40 degrees 53 minutes, along which parallels the scale shall be exact.
The origin of coordinates is at the intersection of the meridian 77 degrees 45 minutes west
longitude and the parallel 40 degrees 10 minutes north latitude. This origin is given the
coordinates n= =0 meters; e= =600,000 meters.
The Pennsylvania Coordinate System of 1983, South Zone, consists of a Lambert conformal
projection of the North American datum of 1983, having a central meridian of 77 degrees 45
minutes west. The northern standard parallel is latitude 40 degrees 58 minutes and the southern
standard parallel is latitude 39 degrees 56 minutes, along which parallels the scale shall be exact.
The origin of coordinates is at the intersection of the meridian 77 degrees 45 minutes west
longitude and the parallel 39 degrees 20 minutes north latitude. The origin is given the
coordinates n= =0 meters; e= = 600,000 meters.
Standard conversions of coordinates from meters to feet will be computed using the United States
survey foot with a definition of 1200/3937 m= = United States survey foot.
The position of the Pennsylvania Coordinate System shall be as marked on the ground by
fundamental triangulation or traverse stations established by the National Geodetic Survey,
formerly the United States Coast and Geodetic Survey for first-order and second-order work,
whose geodetic positions have been rigidly adjusted on the North American datum of 1927, and
redefined on the North American datum of 1983 and whose plane coordinates have been
computed on the system here defined. Such stations, established by the National Geodetic Survey,
formerly the United States Coast and Geodetic Survey, and any other triangulation and traverse
stations which have been established in accordance with the standards of accuracy and
specifications by the Federal Geodetic Control Committee of the United States Department of
Commerce or in accordance with the requirements of the State department authorized to
administer this act, may be used for establishing a survey connection with the Pennsylvania
Coordinate System.
1937, June 2, P.L. 1208, § 5. Amended 1992, Dec. 16, P.L. 1224, No. 161, § 1, effective in 60
days.
Historical and Statutory Notes
Transferred from 76 P.S. § 146 in 1978.
The 1992 amendment substituted "National Ocean Survey/National Geodetic Survey (formerly the
United States Coast and Geodetic Survey)" for "United States Coast and Geodetic Survey" and
"degrees" and "minutes" for shorthand notation; in the first and second full paragraphs, inserted
"of 1927"; inserted the third to fifth paragraphs; and in the sixth paragraph, in the first sentence
deleted", in conformity with the standards adopted by the United States Coast and Geodetic
Survey" preceding "National" and inserted "and redefined on the North American datum of 1983",
and in the second sentence substituted "established in accordance with the standards of accuracy
and specifications by the Federal Geodetic Control Committee of the United States Department of
Commerce" for "definitely established by".
xvi
Advanced Technology Solutions, Inc., http://www.atsincorp.com/Project_Web_solutions/PAMS3.pdf
xvii
MapServer Open-Source OGC-compliant Internet GIS Mapping Server, http://mapserver.gis.umn.edu/
xviii
Typical PAMS datasheet - http://www.penndotpams.org:8080/pams/pdf/574.pdf
xix
Purdon’s Pennsylvania Statutes, Title 68 § 956.
Coordinates, restrictions of concerning public records
No coordinates based on the Pennsylvania Coordinate System, purporting to define the position of
a point on a land boundary, shall be presented to be recorded in public land records or deed
records unless the licensed land surveyor in charge attaches a certificate regarding the beginning
coordinate source, and adheres to third-order geodetic surveying procedures or better, in effect at
the time of the survey as outlined by the Federal Geodetic Control Committee.
1937, June 2, P.L. 1208, § 6. Amended 1992, Dec. 16, P.L. 1224, No. 161, § 1, effective in 60
days.
Historical and Statutory Notes
Transferred from 76 P.S. § 146 in 1978.
The 1992 amendment rewrote the section, which prior thereto read:
"No coordinates based on the Pennsylvania Coordinate System, purporting to define the position
of a point on a land boundary, shall be presented to be recorded in public land records or deed
records unless such point is within one-half mile of a triangulation or traverse station established
as prescribed in section 5 of this act, unless the State department authorized to administer this act
shall by its rules and regulations increase or decrease such one-half mile distance for the whole
Commonwealth or any area or areas thereof."
xx
NOAA Manual NOS NGS 5 “State Plane Coordinate System of 1983”