Spatial Modeling and Analysis in ArcGIS
Spatial Modeling and Analysis in ArcGIS Kevin Armstrong
Agenda
•
•
Modelbuilder -
Brief Intro
-
Working with variables
Network Analysis •
•
Drive Time
Spatial Analyst •
Zonal Tools
•
Weighted Overlay
Required knowledge for building models?
•
•
Know how to use geoprocessing tools -
Complex operations are accomplished by combining simple operations
-
Learn how to combine tools in the correct order
Know how to use ModelBuilder techniques
Making a Model a Tool
•
Creating model elements for parameters
•
Setting data type on model elements
•
Setting filters on model parameters
•
Setting symbology on model parameters
•
Using variables for environment setting
•
Using the feature set data type to make models interactive
Modelbuilder
Buffer and Clip Example
•
Make the model interactive
Parcel Report Example
•
Given a parcel id, report all the parcels within 500 feet
•
Create a model where only the parcel id is entered
•
Export the list of parcels to an html file
Model Variables
Parcel Report: Create a variable for the parcel id
•
Create a variable for the parcel id in the model -
Use the “String” data type
•
Rename the variable to “ParcelID”
•
Make the variable a model parameter
Parcel Report: in-line variable substitution
•
Note the single quotes around the variable name -
You have to supply proper quoting in the expression
In-line variable substitution = flexibility
•
Any string or path parameter can include in-line variables
•
Use %% to indicate in-line variable
•
Keywords: Variable Names - Environment setting names - Built in keywords - %n% is the current iteration number - %i% is the current list index - %v% is the current series value -
In-line Variable Substitution Examples
•
Calculate Value expression – %StartYear% + %n%
•
Calculate Field expression – !shape.Area! * %conversion_factor% – [airport_id] = “%airport_id%” –
•
Make sure to include quotes in the expression!
Path to dataset – %scratchworkspace%\out.shp – Directory\out%n%
Parcel Report: Export to Html
•
Download “Table to Html” tool -
•
http://resources.esri.com/geoprocessing/index.cfm?fa=code GalleryDetails&scriptID=15712
Also includes “Table to Excel” -
Shows how to call Excel from python.
Use model iteration
Network Analyst
Drive Time Demographics Example
•
For a location, determine the population within drive time zones
Drive Time
Drive Time Demographics
•
Use Service Area Network Analysis Layer
•
Use Add Locations to add the drive time source
•
Use Solve to compute the drive time zones
Select Data Tool
•
The Select Data tools is used to expose sub-datasets from the results of tools like Solve, Import from CAD, Split
Select Data Example
•
Use Select Data to get the “polygons” sub-layer from the Service Area Layer
Model Only Tools
•
Select Data
•
Calculate Value
•
Merge Branch -
These tools are only useful in ModelBuilder
-
The are not needed in scripting
Drive Time Demographics
•
Use Dissolve with statistics fields to sum the population by drive time zones
Managing model tool parameters
•
Variable Name = Parameter Label/Name
•
Variable Data Type = Parameter Data Type
•
You can change “Optional” to “Required”
•
You can specify a filter
•
You can specify output symbology
How to control the parameter filter
•
Model Properties/Parameters property page
•
Filter Property -
For the string data type, specify a choice list
-
For the feature class data type, specify the geometry type: Point, Line, Polygon, …
How to control the symbology of the output
•
Set the symbology property on the output variable
Spatial Analyst
ArcGIS Spatial Analyst
•
Integrated raster and vector spatial analysis tools
•
Extension product that adds functionality to ArcGIS Desktop, Engine, and Server
Key Features of Spatial Analyst
•
Over 170 geoprocessing tools
•
Analysis on all raster formats
•
Analysis on all vector formats
•
Full support of selections
•
On-the-fly projections
•
Calculator with Map Algebra syntax
•
Great developer experience
Spatial Analyst Overview
Density Mapping
•
Count occurrences of a phenomena within an area and distribute it through the area.
•
Use points or lines as input. -
Population per Km2
-
Road density per Mi2
Zonal Overlay
•
A zone is all the areas/cells with the same value
•
Calculate a statistic within the zones for each cell in a raster
•
Input zones can be feature or raster
•
Output as a raster, summary table, or graph -
Max flow length in each watershed
-
Median income in each ZIP CODE
-
Mean elevation per vegetation zone
Zonal Overlay (cont.) Slope Mean Slope per Watershed
Watersheds
Zonal Histogram
•
•
Create histograms of cell counts within Zones -
Same zone definitions as Zonal Statistics
-
Zones can also be classes defined in the renderer
Investigate frequency/distribution of one dataset within classes of another dataset •
Slope distribution within Landuse classes
•
Rainfall distribution within Elevation classes
•
Crime distribution by beat
Zonal Tools
The Weighted Overlay tool
•
Assign weights and combine multiple inputs
Weighted Overlay
•
Perform Weighted Overlay analysis for suitability modeling “where is the best place” -
Weight layers
-
Weight classes
-
Supports NoData and restricted values
-
Easier to use, explain, and modify than using reclass and map algebra
Weighted Overlay
Agenda
•
•
Modelbuilder -
Brief Intro
-
Working with variables
Network Analysis •
•
Drive Time
Spatial Analyst •
Zonal Tools
•
Weighted Overlay
Required knowledge for building models?
•
•
Know how to use geoprocessing tools -
Complex operations are accomplished by combining simple operations
-
Learn how to combine tools in the correct order
Know how to use ModelBuilder techniques
Making a Model a Tool
•
Creating model elements for parameters
•
Setting data type on model elements
•
Setting filters on model parameters
•
Setting symbology on model parameters
•
Using variables for environment setting
•
Using the feature set data type to make models interactive
Modelbuilder
Buffer and Clip Example
•
Make the model interactive
Parcel Report Example
•
Given a parcel id, report all the parcels within 500 feet
•
Create a model where only the parcel id is entered
•
Export the list of parcels to an html file
Model Variables
Parcel Report: Create a variable for the parcel id
•
Create a variable for the parcel id in the model -
Use the “String” data type
•
Rename the variable to “ParcelID”
•
Make the variable a model parameter
Parcel Report: in-line variable substitution
•
Note the single quotes around the variable name -
You have to supply proper quoting in the expression
In-line variable substitution = flexibility
•
Any string or path parameter can include in-line variables
•
Use %% to indicate in-line variable
•
Keywords: Variable Names - Environment setting names - Built in keywords - %n% is the current iteration number - %i% is the current list index - %v% is the current series value -
In-line Variable Substitution Examples
•
Calculate Value expression – %StartYear% + %n%
•
Calculate Field expression – !shape.Area! * %conversion_factor% – [airport_id] = “%airport_id%” –
•
Make sure to include quotes in the expression!
Path to dataset – %scratchworkspace%\out.shp – Directory\out%n%
Parcel Report: Export to Html
•
Download “Table to Html” tool -
•
http://resources.esri.com/geoprocessing/index.cfm?fa=code GalleryDetails&scriptID=15712
Also includes “Table to Excel” -
Shows how to call Excel from python.
Use model iteration
Network Analyst
Drive Time Demographics Example
•
For a location, determine the population within drive time zones
Drive Time
Drive Time Demographics
•
Use Service Area Network Analysis Layer
•
Use Add Locations to add the drive time source
•
Use Solve to compute the drive time zones
Select Data Tool
•
The Select Data tools is used to expose sub-datasets from the results of tools like Solve, Import from CAD, Split
Select Data Example
•
Use Select Data to get the “polygons” sub-layer from the Service Area Layer
Model Only Tools
•
Select Data
•
Calculate Value
•
Merge Branch -
These tools are only useful in ModelBuilder
-
The are not needed in scripting
Drive Time Demographics
•
Use Dissolve with statistics fields to sum the population by drive time zones
Managing model tool parameters
•
Variable Name = Parameter Label/Name
•
Variable Data Type = Parameter Data Type
•
You can change “Optional” to “Required”
•
You can specify a filter
•
You can specify output symbology
How to control the parameter filter
•
Model Properties/Parameters property page
•
Filter Property -
For the string data type, specify a choice list
-
For the feature class data type, specify the geometry type: Point, Line, Polygon, …
How to control the symbology of the output
•
Set the symbology property on the output variable
Spatial Analyst
ArcGIS Spatial Analyst
•
Integrated raster and vector spatial analysis tools
•
Extension product that adds functionality to ArcGIS Desktop, Engine, and Server
Key Features of Spatial Analyst
•
Over 170 geoprocessing tools
•
Analysis on all raster formats
•
Analysis on all vector formats
•
Full support of selections
•
On-the-fly projections
•
Calculator with Map Algebra syntax
•
Great developer experience
Spatial Analyst Overview
Density Mapping
•
Count occurrences of a phenomena within an area and distribute it through the area.
•
Use points or lines as input. -
Population per Km2
-
Road density per Mi2
Zonal Overlay
•
A zone is all the areas/cells with the same value
•
Calculate a statistic within the zones for each cell in a raster
•
Input zones can be feature or raster
•
Output as a raster, summary table, or graph -
Max flow length in each watershed
-
Median income in each ZIP CODE
-
Mean elevation per vegetation zone
Zonal Overlay (cont.) Slope Mean Slope per Watershed
Watersheds
Zonal Histogram
•
•
Create histograms of cell counts within Zones -
Same zone definitions as Zonal Statistics
-
Zones can also be classes defined in the renderer
Investigate frequency/distribution of one dataset within classes of another dataset •
Slope distribution within Landuse classes
•
Rainfall distribution within Elevation classes
•
Crime distribution by beat
Zonal Tools
The Weighted Overlay tool
•
Assign weights and combine multiple inputs
Weighted Overlay
•
Perform Weighted Overlay analysis for suitability modeling “where is the best place” -
Weight layers
-
Weight classes
-
Supports NoData and restricted values
-
Easier to use, explain, and modify than using reclass and map algebra
Weighted Overlay
