Module 1: Introduction to the course
What is an ArcMap mxd file? Use ArcGIS help documentation to find the answer
ArcMap documents
When you save a map you have created in ArcMap, it will be saved as a file on disk. This is an ArcMap
document and is referred to as a map document or mxd since the file name extension (.mxd) is
automatically appended to your map document name. You can work with an existing .mxd file by
double-clicking the document to open it. This will start an ArcMap session for that .mxd file.
Map documents contain display properties of the geographic information that you work with in the
map—such as the properties and definitions of your map layers, data frames, and the map layout for
printing—plus any optional customizations and macros that you add to your map.
After reading the light rail project document, answer the following questions:
1. The methodology used in this course to design a light rail between Wageningen and Ede has
three main project phases/components. Write down at least three keywords or phrases
associated with each component that you think are important.
Component a:
Pre-processing: Processing required to get project source data.
Component b:
Calculate a suitable lightrail corridor and route using suitability factors/weights related to
topographic data as main source.
Component c:
Revise calculated route, use visual assessment and on-line interactive digitizing
Component d:
Assess whether the designed light rail fulfils the 70% population criterion within 5-10 minute
walking distance. If the designed light rail does not fulfil this criteria redesign it.
Component e:
Compute costs dependent upon lightrail construction requirements, create one cost
overview table.
Component f:
Presentation of the results of the project. In this project, a map of the designed light rail
route, computed suitability corridor and a table of the different cost aspect along with the
total costs are required. Additionally, the designed light rail route and and corridor must be
published in Google earth so it can be presented to the general public.
Note: Components c&d can also be combined into one component when the revised lightrail
route is assessed by means of the criterion 70% population walking distance.
2. Using your basic knowledge of GIS, what type of GIS data handling types do you think you
will need to accomplish the first project component?
Queries, Transformations and Process/Alter Operations
Queries:
Query is a term coming from database information systems. It stands for QUEstion and ReplaY.
Queries create a subset of the original data input. This means the described information does not
change. For example, the attributes and the domain values of the attributes of a dataset does not
change when using a query.
Basically there are two types of queries in GIS. A query based on logical expression using attribute
information. For example, select all polygons where LanduseCode = 'forest'. The logical expression in
this example is LanduseCode = 'forest'. A spatial query is the other basic query type. For example,
select all buildings within the municipality of Wageningen.
Transformations:
In GIS, transformation are related to geometric change. The original definition of the data does not
change with this data handling type.
Examples are:
- coordinate transformations. For example transforming the data from the Geographic map
projection in defined in degrees to WGS84 in meters.
- format transformation. For example, vector to raster and vice versa
- attribute values transformation. For example, translating landuse values in Dutch to English
Process/Alter:
This data handling type changes the input information into new information. For example, making a
buffer around the design light rail that represents a walking zone. Also, spatial overlays where the
information of input data is joined to one another by means of there location. For example, using the
Union spatial overlay to create one dataset of landuse and soil, belongs to this data handling type.
What are the fundamental purposes of geoprocessing according to ESRI?
Automation of processing workflows. This allows you to repeat calculations and also share your workflow
with others.
What does geoprocessing allow you to do within ArcGIS?
Geoprocessing allows you to chain together sequences of tools.
What is a script tool according to the essential geoprocessing vocabulary of ESRI?
A script tool is a Python or another programming language script (program). These non-standard scripts
can be integrated into models by making the script into a script tool and adding the script tool to a model.
This can be used when Python or other scripting language logic is needed to enhance a model or to access
an external package or program from within ArcGIS.
What is a toolbox? What is the difference between system- and custom toolboxes?
A Toolbox is a collection of processing tools
A System Toolbox are tools developed and maintained by ESRI
A Custom Toolbox is developed and maintained by the user. These toolboxes have models that can use
system toolbox tools or user made scripts.
What are geoprocessing environments?
Environment settings can be thought of as additional parameters that affect the execution of a tool.
There four different levels of setting geoprocessing environments. What level settings are there?
Module 2: Application Building
Fill-in the table below. Use the presented index-code and the light rail goals and methodology
document. Use the roman number I for the project indication.
Application index-code for project,
application, application component
Brief description of what each component does
IAa
Data preprocessing: Getting source project data
IAb
Calculate light rail route and corridor according to given weight
factors
IAc
Adapt computed light rail where necessary to meet project
criterion of 70% population within 5-10 minute walking
distance
IAd
Compute cost lightrail
IAe
Make a map presentation of best lightrail route and corridor
Which part of the index-code is the same for all components? Describe in your own words why this
is the case.
IA
This table actually defines the framework of your application/working solution. Please keep this
framework in mind when you create new datasets. It should be clear to yourself and others (for
example your
1. What does this toolset represent in the application-component-step project model?
The toolbox 01_IA_Geotools_python_toolbox.tbx represents a library of general tool(s) that
are required in most project applications. These tools can be copied to the project
application toolbox to make sure they are accessible after the end of the project. This is
necessary to guarantee the repeatability even after the project has ended.
2. How many application component-steps do you think you will need to solve the second
methodological component proposed in light rail goals and methodology concerning the
project criteria requirement that 70% of the population in the research/study area must be
able to walk to the line rail route within 5-10 minutes? Explain your answer.
In principal this component can be calculated in one step will several individual tool actions.
This is possible because there is no human interference required to break the calculation
flow. However, if the computations are lengthy in time, it is best to consider splitting the
computation into more steps. In practice this is often left up to the judgment and experience
of the application developer. Reasons to consider splitting up one step components into
several steps are discussed in Module 2.1.2.

How many:
1. Model Input datasets are there?
3 input datasets are required. b_grid_stat_wag, b_grid_stat_ede and b_wgtgrd (two
seperate data input boxes are used for this one dataset)
2. Model Output final datasets are there?
2 datasets: pr_computed_lr and pr_lr_corridor
3. Model Output intermediate datasets are there?
10 intermediate or temporary datasets are created during the calculation.
4. Processing actions?
10 processing actions
5. Option input parameters?
2 option input parameters: Path type and Map Algebra Expression

The Final output data have a prefix in their name.
What is the prefix?
pr_
What do you think this prefix stand for?
project result

Fill-in the following table, use the ArcGIS help to find additional information:
Define what type of basic GIS operation it is; (basic GIS operation types are Transformations,
Queries, and Process/ Alter Operations).
Cost Distance : Process/Alter Operations
Cost Path : Process/Alter Operations
Corridor : Process/Alter Operations
Compute Corridor Zone : Query + Process/Alter Operations
Raster to Polyline : Transformation
Compute corr(idor) zone (reclassify corridor into 100 intervals; these intervals represent the increase
of suitability cost in percentages : 0% = the Costpath) : Process/Alter Operations
Zonal Statistics Compute Minimum : Process/Alter Operations
Compute (corridor) threshold value grid : Query + Process/Alter Operations
Create lightrail corridor (keep zone interval information): Query
Raster to polygon : Transformation
After reading "The need for notations", how many Geodatabase(s) do you require for your
light project?
3 are required: project geodatabase, component geodatabase, temporary geodatabase

What names do you proposes for your Geodatabase(s)?
IA_Lightrail_1_project_gdb
IA_Lightrail_2_component_gdb
IA_Lightrail_3_step_gdb

What name do you propose for your light rail application toolbox?
00_IA_Lightrail_Aplication_<name_application_developer(s)>

What names do you propose for the first 2 toolset components: pre-processing and
computed light rail route and corridor?
IAa_preprocessing and IAb_compute_lightrail_route_and_corridor:
For practical reasons these can be abbreviated to
a_preprocessing and
b_compute_lightrail_route_and_corridor
Module 3: Setting up your Geo-processing workspace
To which project application level the created toolbox corresponds ?
1. Application
2. Application-component
3. Application-component-step
The toolbox corresponds to the Application level.
It contains the all components and steps of the application.
What is a workspace? And What is the difference between a Current and Scratch workspace?
A workspace is the location to store and manage geographic information for ArcGIS.
A workspace can be a folder, or a database. It can contain datasets, toolboxes, and other ArcGIS
documents.
The current workspace:
Tools that honor the Current Workspace environment setting use the workspace specified as the
default location for geoprocessing tool inputs and outputs.
The scratch workspace:
Tools that honor the Scratch Workspace environment setting use the specified location as the default
workspace for output datasets. The Scratch Workspace is intended for output data you do not wish
to maintain. The primary purpose for the Scratch Workspace environment is for use by ModelBuilder.
ModelBuilder needs a workspace to write intermediate datasets—datasets that are of no use once a
model is run. Although its primary purpose is for ModelBuilder, there may be times when you want
to set it for tool dialog boxes.
Why is it wise to set an output coordinate system within a GIS project?
In principle all GIS datasets should have a projection defined. For datasets that are produced using the
Modelbuilder of ArcGIS, the output dataset will get by default the same coordinate system as the input,
even if the input was different from your projects coordinate system.
As such you as a user want to set the coordinate system of your resulting data, and don't want to leave the
desicion to the system.
When a dataset has a different coordinate system then RD_New, the output dataset is automatically
transformed into RD_New with this environment setting. What type of changes to an output dataset can
you expect when this transformation is applied to an output vector and raster dataset?
Vector changes:
Transforming a vector dataset will basically reproject the most primitive feature elements, a point, from
one coordinate to another. So the shape and location of a feature will be changed. The same happens when
tranforming lines and polygons, the points of which the lines and polygons are build, are reprojected from
one coordinate system to another, and the lines and polygons are reconstructed.
Raster changes:
Transforming raster datasets will change the content of the dataset, as the values of a rastercell will be
aggregated or desaggregated. The resampling method usewd is very important, and depends on the
datascale of the raster datset.
What is the difference between XY Resolution and XY Tolerance?
The XY Resolution refers to the number of significant digits used to store x,y coordinate values
The XY Tolerance refers to the minimum distance between coordinates before they are considered equal
What is the difference between M values and Z values?
M-values (Measure values) are related to lines that form a route in a network system. Route's geometry
differs from other linear geometry in that instead of being a collection of x,y coordinates, a route's
geometry is a collection of x,y,m values. In the following example, there is a route that is 110 miles long in
the real world. Displaying such a route on a map might look something like this.
A route's geometry is a polyline with measures.
The vertices that make up this polyline might look something like this.
Each vertex in a route has an x,y,m value. Measure values are only stored at the
vertices. Measure values between vertices are interpolated.
Z-values represents the height of an object.
In this course all vector data do not have height values nor m-values!! Therefore it is best to disable them in
your environment settings.
Module 4: Pre-processing
What is a MXD file?
In ArcMap, this file contains the properties of the map layout, its associated layers, tables, charts,
and reports. Also the environment settings concerning tool calculations are saved.
Map documents can be printed or embedded in other documents. Map document files have a .mxd
extension.
Does a MXD file contain the stored data?
No! The document only saves links to the data.
What is the perimeter (border length) and area in meters?
(This area will be the project extent of the lightrail project.)
The perimeter can be calculated using the determined coordinates for the minimum/maximum x and
y as: 2*(maxX - minX) + 2*(maxY - maxX)
What is the script filename?
CreateClipBox.py
What are the scripts parameter names and their corresponding Data Types?
Output Clip Feature : Feature Class
Xmin : Any value { This means any numeric value can be given. }
Ymin : Any value { Therefore integer values (for example 401500) or }
Xmax : Any value { Real values (for example 401500.00) can be used }
Ymax : Any value { as an input value for the XY min/max coordinates }
Coordinate System : Spatial Reference
Why do you think this difference exists?
The difference between double clicking a model and drag and drop it on a model is its repeatability.
In the first case, the model parameters need to be added each time the tool is used. The tool is used
with a graphical user interface GUI.
When using a tool in a model, the parameter values will be saved in the model and the model-actions
can be repeated with exactly the same environment- and in- and output parameters settings at any
moment.
The output format of the model action is a feature class, search in the ArcGIS help for a description of this
format, and give at least three other data formats that can be used in the ModelBuilder.
Feature classes are homogeneous collections of common features (vector objects), each having the
same spatial representation, such as points, lines, or polygons, and a common set of attribute
columns, for example, a line feature class for representing road centerlines. The four most commonly
used feature classes in the geodatabase are points, lines, polygons, and annotation (annotation is the
geodatabase name for map text: not discussed during this course).
Other data formats are raster, tables, tin, kml etc.
Although the CLIP operations combines two feature dataset to create a new (geometrically altered)
output feature dataset, why is a CLIP feature operation not considered a spatial overlay operation?
The CLIP operation is a spatial query operation. It selects features within a given area. The original
feature/object definition does not change. This means the attributes of each feature stays the same.
A spatial overlay on the other hand, JOINS the object definitions of both input feature classes. This
joining operation create a new object definition, the combined attributes of both input feature table.
Due to the entity change you create new features with a new object definition. Using a spatial
overlay when you should use a spatial query can have severe consequences in your project. For
example, redundant attributes in your output dataset. This can cost a lot of extra computation time
and storage space. This could result in long delays when applying when applying your results later in
the project.
Why are all the clipped datasets considered to be project source (ps_) datasets?
They are the first results from the external geodatabase. This marks the starting point of your
application with the data you want for your project.
Why does ps_elevation_point not have an attribute SHAPE_LENGTH?
Point features do not have a length and/or area, it is just a x-y position.
Why is the attribute SHAPE_LENGTH kept in the other datasets?
Shape_length is part of the feature's geometry, this field together with shape_area for polygons
cannot be removed in geodatabases.
Why is it not necessary to give a Summary Field?
The Summary field describes the attribute you want to use to get the unique values from. For those
of you familiar with SQL it is the GROUP BY attribute.
Why is LONG an appropriate Field Type in this case?
In a long integer you can store whole numbers (without decimals), with a minimum of 2,147,483,648 to a maximum of 2,147,483,647.
Why do you think this is necessary?
When adding a field you change the structure of a table. This means you do not create a new table
but alter the input table, so the input table is the output table but with a new attribute.
In ArcGIS when you apply any FIELD tool the input table and output table will always be the same.
Why is this model option not desired during application development?
Intermediate data, is created only for the purpose of connecting tool output to another tool
calculation in the ModelBuilder. In the development phase of a project you would like to be able to
view all of the results.
Why are the other output databoxes have a greyed out Intermediate option?
As for the Add field, the calculate field and delete field will only change values of an attribute, or
delete attributes in a table. The entity of the table does not change, that is why the input and the
output contain the same table.
What does this model actually make?
This model merges all individual reclassifications tables created from each top10 polygon feature
dataset into one project reclassification table. This basic reclassification table is used later to assign
each top10 feature polygon a suitability weight. These suitability weight factors are used to compute
a so-called "cost" path and cost corridor from Ede to Wageningen en vice versa. This will be discussed
in further detail in Module 12.
What does the MERGE tool do?
The MERGE tool creates a new table and adds all records, (rows of the table) from the input tables.
This means that multiple records that have exactly the same values per row can still occur in your
reclassification table when reclassification definitions are found in more than one dataset. To make
sure this does not take place the Frequency tools is applied again (see question: Why is the
Frequency tool used after the Merge tool?)
Where did you save the table a4_merged_freqency_tables and why?
This table should be saved in the temporary geodatabase. It is only needed in this model to create
the final output project reclassification table.
Why is the Frequency tool used after the Merge tool?
To remove possible multiple records that have exactly the same values per row like in the case with
the attribute values coming from the houses and buildings datasets.
Where did you save the table ps_basic_reclass_table?
From this table suitability reclassification tables are made for different scenarios within the project. It
is a major starting point for all calculations within this project. Therefore it is very important when it
comes to repeatability of your work. This is why it should be saved in the project geodatabase.
The previous table starts with ps. What does this stand for?
project source dataset
Module 5: Relational Databases
What are the standard geometric attributes for the 3 different features types (Polygon, Line,
Point)?
Polygons: Shape_type: Polygon, Shape_length, Shape_area
Line: Shape_type: Polyline, Shape_length
Point: Shape_type: Point
Why is the following attribute table not possible in ArcGIS?
Combined geometric feature classes are not allowed. It is only possible to have one geometric type in
a feature dataset.
How many bytes does a short integer contain and what are the minimum and maximum integer
values that can be stored in this datatype?
Data type
Storable
range
Size
(bytes)
Applications
Short
integer
-32,768 to
32,767
2
Numeric values without fractional values within
specific range; coded values
How many bytes does a long integer contain?
Can the height of the Mount Everest be saved in a long integer datatype when the height of the
Mount Everest must be expressed in 1000ths of a millimetre (µ's)?
Mount Everest is 8,848 metres = 8848000 mm. A long integer is required.
Data type
Storable
range
Size
(bytes)
Applications
Long
integer
2,147,483,648
to
2,147,483,647
4
Numeric values without fractional values within
specific range
Someone wants to the municipality code number of the Netherlands. The code numbers range
from 10 to 999. What datatype is best used?
Short Integer
Someone wants to height as whole numbers. The last digit represents millimetres. The height
range (domain) is -12000000 to 9000000. What datatype is best used?
Long Integer
What datatype is best used to calculate results that can have a very big number with 15 digits
precision behind the decimal place? For example the number 123456789.123456789012345
Double precision Floating Point
Data type
Storable range
Size
(bytes)
Applications
Double-precision
floating-point number
(double)
Approximately 2.2E308 to 1.8E308
8
Numeric values with fractional
values within specific range
When would you use a Blob datatype?
A Binary Large Object, also known as a blob, is a collection of binary data stored as a single entity in
a database management system. Blobs are typically images, audioor other multimedia objects,
though sometimes binary executable code is stored as ablob. Multimedia objects are also used as
Now that you have gained experience in making a table from a worksheet layout, state 3
differences between a worksheet and a table.
Spreadsheet
Table
cell based
row based
no fixed structure
fixed structure defined by columns
(attributes/fields)
This fixed structure is also called entity or
object definition
can have a formula as well as values in a cell
can only save values. It is possible to have
formulas but this is only supported in a table
view.
no fixed query language applicable
tables in relational databases very often use a
standard query language like SQL
Describe briefly what the Tablet o Table tool does.
Converts an input table to a geodatabase table.
What are the input parameters of this tool?

Input rows

Output location

Output table

Field Map
There are two parameters used to construct the output table, which ones?
The output table is constructed on basis of the Output location (the geodatabase) and the Output
table (name of the table)
What storage datatypes are used in the table ps_demography?
There are only 2 storage datatypes you can expect; Double precision floating point and text. In
modern databases the need to differentiate in number data storage types is declining. Storage space
is no longer an issue. However the number of attributes/fields is. The transaction time of records
during a query is highly dependent upon the number of attributes. It is therefore good practice to get
rid of redundant attributes is a table.
Do these datatypes correspond to the original datatypes in the Excel file?
Depending upon the region setting of your computer number attributes can automatically change to
text. For example in the Dutch setting a decimal point is represented by a comma. In the table
conversion from spreadsheet to table in a geodatabase this attribute will become text instead of a
number.
Which relation type is needed to present all years and which relation type does ArcGIS support in
your present join?
1 (polygon) : m (years) is required. ArcGIS supports m (features) : 1 (record/row join table)
In which geodatabase did you save a6_neighborhood_demogr_int? Why?
This table a temporary table. This table is used to join the demographic data to the neighbourhoods
before the null attribute rows are removed by the select tool. It must be saved in the steps
geodatabase.
In which geodatabase did you save a6_neighborhood_demogr? Why?
Unlike the table a6_neighborhood_demogr_int, the table a6_neighborhood_demogr will be used in
another model later in the application. Therefore it must be saved in the components geodatabase.
This table is not considered important enough to be a project result dataset.
What is the expression you used to select the correct features with the select tool.
{fieldname selected by user} IS NOT NULL : an example is "GWB_CODE" IS NOT NULL
Do you have redundant attributes in your new neighbourhood attribute table?
The attributes/fields BU_CODE and GWB_CODE represent neighbourhood code numbers. Although
the attribute names are different the meaning and content is the same. This means that the
attribute/field GWB_CODE is considered redundant. The other attributes/fields of the join table are
unique in meaning and description.
How do you know which population density belongs to which year?
The attribute/field name gives no indication of what the year is. When you switch on the option
Show Field Aliases, the names are identical. ArcGIS automatically generates a sequence number
extension to the second name. For example the attribute/field name YEAR is in both tables. The
second name becomes YEAR_1 for the first join year_12 for the second and so on.
Which of the incoming datasets need to be copied first, and why?
The ps_Neighborhoods has to be copied first. When performing a join, the join table will be
physically joined to the Input table, so the input will be changed. As the input table is part of your
project source data, it must be avoided this data will be messed up, so a copy is made first.
Where did you save your final result? What name did you give this file?
The results should be saved in the Project geodatabase, as it is part of you project source data.
the name should start with ps, together with a logical name: ps_BasicReclassTableWithMeaning.
Module 6: Pre-processing: Giving attributes values using the model
builder
What is a table view?

Feature layers and table views have the same function in ArcGIS.

A (feature or Raster) layer is what you see in the ArcMap table of contents. A layer contains
the path to the dataset along with symbology information and feature or row selection
information.

Table views are the table equivalent of a layer. In principle they point to the selected records
in the related table.
Where are the table view selections saved?

They are stored in memory and are the same as the table view created when a table is added
to ArcMap.
What happens to table view selections when you exit ArcMap?

Table views are erased from memory. However, when ArcMap is re-started with the MXD
file where they are defined in the layer overview, the views are re-established in memory.
Why does the Join Field calculation take so long in comparison with the Copy Features calculation?

Every feature (row in the feature attribute table) is altered (the original plus the new
joined attributes) to create a new entity. This means the row is read (selected), altered and
thereafter written to the file. Any Copy tool only reads (selects) and writes; no alteration
are made to the existing data.
Module 7: Digital Elevation Models
Who was the developer of this programme?

Topo to Raster tool is an interpolation method specifically designed for the creation of
hydrologically correct digital elevation models (DEMs). It is based on the ANUDEM program
developed by Michael Hutchinson (1988, 1989). See Hutchinson and Dowling (1991) for an
example of a substantial application of ANUDEM and for additional associated references. A
brief summary of ANUDEM and some applications are given in Hutchinson (1993). The
current version of ANUDEM used in ArcGIS is 4.6.3.
A specific interpolation technique is used to determine the terrain surface. Which one is it?

The interpolation procedure has been designed to take advantage of the types of input data
commonly available and the known characteristics of elevation surfaces. This method uses an
iterative finite difference interpolation technique. It is optimized to have the computational
efficiency of local interpolation methods, such as inverse distance weighted (IDW)
interpolation, without losing the surface continuity of global interpolation methods, such as
Kriging and Spline. It is essentially a discretized thin plate spline technique Wahba, 1990)
This technique has been modified to do what?

It is essentially a discretized thin plate spline technique (Wahba, 1990) for which the
roughness penalty has been modified to allow the fitted DEM to follow abrupt changes in
terrain, such as streams and ridges.
What is the purpose of the drainage enforcement process?

The purpose of the drainage enforcement process is to remove all sink points in the output
DEM that have not been identified as sinks in the input sink feature dataset. The program
assumes that all unidentified sinks are errors, since sinks are generally rare in natural
landscapes (Goodchild and Mark, 1987).

Drainage enforcement can also be supplemented with the incorporation of stream line data.
This is useful when more accurate placement of streams is required.
What is a sink in a hydrological model and why are these important to know?

The drainage enforcement algorithm attempts to clear spurious sinks by modifying the DEM,
inferring drainage lines via the lowest saddle point in the drainage area surrounding each
spurious sink. It does not attempt to clear real sinks as supplied by the Sink function. Since
sink clearance is subject to the elevation tolerance, the program is conservative when
attempting to clear spurious sinks. In other words, it does not clear spurious sinks that would
contradict input elevation data by more than the value of Tolerance 1.
There are six types of feature dataset inputs possible when using the tool Topo to Raster. Which
inputs require a height field?
There are six types of accepted inputs:

POINTELEVATION — point feature class representing surface elevations. The Field stores the
elevations of the points.

CONTOUR — A line feature class that represents elevation contours. The Field stores the
elevations of the contour lines.

STREAM — A line feature class of stream locations. All arcs must be oriented to point
downstream. The feature class should only contain single arc streams. There is no Field
option for Stream.

SINK — A point feature class that represents topographic depressions. Topo to Raster will not
attempt to remove from the analysis any points explicitly identified as sinks. The Field used
should be one that stores the elevation of the legitimate sink. (Option height field can be
used). If NONE is selected, only the location of the sink is used.

BOUNDARY— A feature class containing a single polygon that represents the outer boundary
of the output raster. Cells in the output raster outside this boundary will be NoData. This
option can be used for clipping out water areas along coastlines before making the final
output raster. There is no Field option for Boundary.

LAKE — A polygon feature class that specifies the location of lakes. All output raster cells
within a lake will be assigned to the minimum elevation value of all cells along the
shoreline. There is no Field option for Lake.
What is a STREAM line feature input? When would you use this input in Topo to Raster?

A line feature class of stream locations.

Applying the ANUDEM (Topo to Raster) procedure successfully…, particularly with reliable
initialisation of elevations on data streamlines in a way that is consistent across the borders
of neighbouring map tiles in low relief areas, (Hutchinson 2009).
An example of low relief area is “Het Binnenveld” between Wageningen and Rhenen.
Do the computed streamlines coincide with the water bodies in your project area?

This should be clear from your own observations.
At what location did you save these TEXT data?

These data are not geodatasets or tables. An appropriate location would be in the folder
extra_data.
Module 9: Aggregate and Erase
Explain in your own words what the purpose is of each action in this test model. Also explain which
"simplification tolerance distance and area" combination you would use in this project. The values
you choose can be different than the given used in this example.
Action 1:
Clipbox: This "Clip area" is defined to reduce the amount of data that results in a reduction of
computation time during development of the model. When the testing is finished this step is
removed from the final model.
Action 2:
Clip: Using the previous defined "Clip area", a subset of the project data is used for testing. Also this
action is removed from the final model.
Step 3: Merge: Merges the houses and buildings into one dataset. This is possible because both
feature datasets have the same entity definition within this model.
Step 4: Simplify Buildings: Simplifies the geometry of the buildings and houses. According to a given
offset tolerance distance vertex points of the border can be removed. The reduction of points also
results in a computation reduction when aggregating the houses and buildings. The minimum area
option removes small buildings and houses. This also reduces computation time in the aggregation
action.
For this project the best tolerance distance should not be too long, because relevant buildings and
houses would be removed. A tolerance distance of 10m is appropriate. Small sheds and garages can
be removed from the project. These types of buildings are usually smaller than 100 m2.
Explain in your own words what the purpose is of this aggregation action in the model. Also
explain which "aggregation distance, minimum area" combination you consider best for this
project.
The aggregation tool merges buildings and houses within a specified aggregation distance and
minimum area. Here again the aggregation distance and minimum area should not be too high. If so,
too many buildings will be merged into one just leaving one homogeneous area of houses and
buildings. The best combination in this project is 25m and 150 m2. 25 meters is realistic because
building blocks are usually within this distance in Wageningen. 150 m2 is also realistic because
individual houses are usually larger than this value.
Please note that the distances and areas used in the simplify building and aggregate tools are highly
dependent upon where the buildings are located. For example in Copenhagen you will have different
values than in Wageningen. There the buildings are more spaciously distributed.
Also when applying the aggregate tool, the features that are smaller than the minimum area value
are used to first calculate the aggregated area. So only the buildings that fall outside of the
aggregations distance and smaller than the minimum area are left out of the calculation.
What does the Mult to Singlepart tool do?
The aggregate tool creates multipart polygon features. In ArcGIS, many features can have the same
set of attribute values. These features can be grouped into one feature multipart reducing the size of
the feature class table considerably. Multiparts are also used to group individual features into a new
feature class. For example the individual polygons in the figure below are grouped to define a
shopping centre.
A multipart feature can be a group of points, lines, or polygons.
Please note! A combination of the points lines and polygons is not allowed in a multipart feature
class.
Why do you think this selection operation is necessary?
After the erase computation, splinter polygons can occur. These polygons are not detectable in the
feature class table when the polygons are defined as multiparts. After converting the multipart
polygons to single polygons, it is possible to select only the bigger polygon(s) describing the preferred
light rail area around secondary roads. By means of this selection the splinter polygons are removed
from further computations.
Module 10: Slope and Surface Flow Accumulation
Exam question examples
A slope of 100% is equal to how many degrees slope?
45 degrees
What is the raster Source type, Pixel type and Pixel depth of the computed slope raster?
When you present the slope dataset in ArcMap, this information can be found in the properties of
the layer in the tabular called "Source". In this case the slope data is defined as follows:
Source_Type: continuous
Pixel_Type: floating point
Pixel_Depth: 32 Bit
Why does the Slope raster not have a Raster Attribute Table?
The slope values are given in decimals. This means each rastercell can have a different value. By
default, ArcGIS does not create a raster attribute table because it can become very big; a large
number of rows in other words. However, it is possible to make this table with the Build Raster
Attribute Table; there is a limitation, it is not possible to build a raster attribute table for a raster
dataset that is a pixel type of 32-bit floating point.
What does the tool Region Group compute?
This tool creates zones where the neighbouring rastercells have the same value. The input raster
must have raster classes. The use of this tool is comparable with the multi to single part in the
vector data environment.
What is the difference between Number of Neighbours to use option Four and Eight in the Region
Group tool?
The four option only use the neighbouring raster cells with a common edge to the centre raster cell.
These neighbouring cells are often referred to as full neighbours. The eight option also uses the
"corner" cells in the calculation.
Which combination of Number of Neighbours and Zone Grouping Method did you use in your
model? Motivate your answer
When you raster zones are long and thin (in other terms the ratio between and area is very big), the
connection between the rastercells to define the zone is defined by the corner cells, for example
steep slopes alongside a dike. In this case it is best to use eight. When the ratio between perimeter
and area slope area is not so big then it is best to use the four option to define the grouped zones.
What a big or small ratio factor is must be decided by the user. It is necessary to explore where you
as a user want to set the ratio threshold between big and small ratios. This can change per study
area.
What does the Flow Direction tool calculate?
To which neighbouring rastercell the steepest descent in height is. When the descent is the same for
more than one cell, the direction coding filter is used. See How flow direction works in the help of
ArcGIS for more background information.
Why should the option "Force all edge cells to flow outward" be turned on in this project?
If this option is turned off, there if a possibility that a stream will re-enter the DEM area by means of
the edge rastercells. It is best to try and avoid this.
What do the accumulated values in the Flow Accumulation tool represent?
Since no weight raster is used as an extra input, it calculates the number of accumulated of cells.
Why is the accumulated threshold value needed in this model?
It is expected that a given number of cells will indicate whether there is enough accumulation to
expect a stream.
What pattern do you distinctively see in this presentation?
The drainage network around the fields.
What does the Expand tool do, in conceptual sense?
It make a zone bigger around the perimeter of the zone by a given number of rastercells, like a buffer
when applying the LIST option.
What is the main direction of the stream runoff pattern?
Does this coincide with your expectations with the river Rhine as the southern boundary of the
project area?
If the Rhine, also called Neder-Rijn in Dutch, where to follow it's natural course, it would flow
between Wageningen en Rhenen in the northerly direction towards Veenendaal and eventually go to
Amersfoort.
The Dutch, having a long history in water management, did not like this option and made a dike
between Wageningen and Rhenen to make sure that all water flows in a westerly direction so that the
agricultural development between Wageningen and Rhenen was and still is not threatened by
frequent floods.
8.a: Vector Buffers
Which ArcGIS tool can you use to connect both tables?
Join Field
Which ArcGIS tools are required to create the new attribute and content?
Add field and Calculate field
There are three datasets involved in this example:
- The pig farm locations
- The Restriction zone buffer distance table
- The Restriction zone area
To which dataset should you create the new attribute and content?
The Restriction zone area
In which GDB must you save these two datasets?
Step: All test data are considered data that can be deleted at any time. This fulfils the use of the Step
GDB in this project.
How does the buffer differ in geometry and thematic sense in the previous results?
In the first method, the method created a buffer around every polygon feature. In the attribute table
the TDN_code and the buffer distance were included.
The second method, created a buffer around every TDN_code class value. In the attribute table the
TDN_code was present, but no buffer distance attribute. In principle, all buffer polygon features of
the first solution were dissolved according to the TDN_code value.
The third method created one buffer and only geometric attributes. No thematic attributes.
Explain in your own words what the DISSOLVE option does during the buffer computation. Use
ArcGIS's help "How Dissolve (Data Management) works" to find more information.
It aggregates features according to unique combinations of attribute values.
Which Buffer solution is required in the light rail project concerning preferred construction area
around main and secondary roads? Motivate your answer.
There is no need to relate to the input attribute information. The buffer zone created is new data;
the preferred building zone area. Further it is not a good option to have a buffer around each
individual road feature, since the result will give many overlapping buffers and make the dataset
unnecessarily large. As a result it will make further calculations more time consuming.
Explain in your own words what a precondition connection in an ArcGIS model does.
A precondition connection can be used to influence the order of the calculation sequence of the
tools in a model. It allows the model developer can manipulate the default order of calculations.
Why is this precondition necessary in this model?
It makes sure the table view calculations, which alters the content of the table, before further
calculations. Otherwise it could occur the attributes values in the following calculations are not
available.
Describe in your words what the three Euclidean tools do:
Euclidean Allocation
This tools allocates cells to the nearest rastercell source or feature; you can set a maximum distance
to determine an allocation; in this way a buffer is created. When a raster is used as source the
nearest rastercell value is allocated to the cell. When using a feature dataset as input the OBJECTID
value is allocated.
Euclidean Distance
It calculates the distance from a cell to the nearest source and saves this value in the cell.
Euclidean Direction
It describes the direction from a cell to the feature the cell is allocated to by the tool Euclidean
Allocation.
The three presented Euclidean results are drawn according to an attribute data scale. Attribute
data scales are:
Nominal, Ordinal, Interval, Ratio or Binary.
Firstly per Euclidean result determine whether the grid has an attribute table or not.
Use the help of ArcGIS and explain why some grids have an attribute table and others do not.
Only the distance has no attribute table. This is because it is a continuous raster dataset. In principal
each rastercell can have a different value.
The other two rasters consist of classes of values. In the help the following is stated: “cells to which
one can assign common attribute values (like main road or north) (“have cell values that represent or
define a class, group, category, or membership”)
What is the data scale of the drawing attribute in the grid made by:
o
Euclidean Allocation; Depends upon the data scale in this case Nominal
o
Euclidean Distance; Ratio
o
Euclidean Direction; Ordinal
Explain why this solution with a Reclass Ascii File is not preferred in a GIS project.
Because this file cannot be saved in the geodatabase, which makes the storage of files more
complicated, including inputs from outside the geodatabases.
What does the ~IsNull mean in your own words?
If in an original raster the value of a cell is NoData / null, it will be assigned a specified value (for
example the value of another raster) in the new raster. If it is not null, it will be assigned another
specified value (for example the value of the original raster).