Module 1: Introductionto the Course

Module 1: Introductionto the course

What is an ArcMapmxd 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 thelight 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, TransformationsandProcess/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 thelight 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 / Computecost 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.

1. How many application component-steps do you think you will need to solve the second methodological component proposed inlight rail goals and methodologyconcerning 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? Explainyouranswer.

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:
• 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)
• Model Output final datasets are there?
  2 datasets: pr_computed_lr and pr_lr_corridor
• Model Output intermediate datasets are there?
  10 intermediate or temporary datasets are created during the calculation.
• Processing actions?
  10 processing actions
• 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 toPolyline : 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 topolygon : 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, temporarygeodatabase

• 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-valuesrepresents 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 aMXD 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.