Suitability modeling workflow using ArcGIS Desktop—Lesson 1: Exploring and deriving data

In this lesson, you will identify and derive criteria for the Habitat submodel, one of the three submodels comprising the Bobcat suitability model. The two other submodels, Food and Security, will be viewed in later lessons. Identifying and deriving data are the first steps in creating a suitability model.

The lesson is divided into four sections:

1. Downloading and preparing the tutorial data
2. Exploring the data and opening and editing the ModelBuilder model
3. Using the Slope tool to derive data from base data (elevation)
4. Using the Euclidean Distance tool to derive data from base data (streams)

ArcGIS Spatial Analyst extension is required for this analysis and you must ensure that it is enabled. See Enabling the Spatial Analyst extension.

These lessons were created in ArcGIS Desktop using version 10.4.1.

Downloading and preparing the tutorial data

1. Download the data package at the beginning of this case study.
2. Browse to the zip file in the Downloads folder.
3. Unzip the zip file named SuitabilityModeling.
4. Copy the unzipped SuitabilityModeling directory (which contains Data.gdb, Output.gdb, the Toolbooxes folder, and SuitabilityModeling.mxd) onto the C drive.

Exploring the data and opening and editing the model in ModelBuilder

1. Open the SuitabilityModeling map document by double-clicking the file.

   

   Visible on the map are three layers: Streams, Elevation, and LandUse.

2. To view just the Streams layer, uncheck the check boxes next to the Elevation and LandUse layers.

   Streams—This layer is a feature dataset representing streams as line segments. Suitable habitat can be found in the dense riparian zones of streams.

   

3. View the Elevation layer by unchecking the check box next to the Streams layer and checking the check box next to the Elevation layer. Click the plus sign to the left of the Elevaton layer check box to view a drop-down key to elevation.

   Elevation—Elevation is continuous raster data that indicates the vertical height above sea level at each location.

   

4. View the LandUse layer by unchecking the check box next to the Elevation layer and checking the check box next to the LandUse layer. Click the plus sign to the left of the LandUse layer check box to view a drop-down key to the land use categories.

   LandUse—Land use is categorical raster data that indicates the type of land cover present at each location.

   

5. To help keep the workflow of building a suitability model organized, the tools used will be kept track of in a ModelBuilder model. Within the SuitabilityModeling folder is a folder named Toolboxes, which contains the ModelBuilder model for this lesson. Open the Catalog window by clicking the icon in the taskbar and access the Toolboxes folder. From the Catalog window, open the SuitabilityModel model within the SuitabilityModelingToolbox toolbox by right-clicking the model and clicking Edit.

   

6. Drag the LandUse, Elevation, and Streams layers from the table of contents into the model and align them vertically. These layers serve as the base data for the Habitat submodel created in this lesson.

   

Using the Slope tool to derive data from base data (elevation)

Ledges are often an important feature of bobcat habitat, but the elevation raster tells us little about where ledges can be found. However, a slope raster indicates where ledges are likely to exist. You will derive a slope raster from the Elevation layer using the Slope tool.

1. The Slope tool requires Spatial Analyst, so turn on the extension by first clicking the Customize tab in the ArcMap taskbar. Choose the Extensions option from the drop-down list, and check the Spatial Analyst check box to turn it on.

   

   

2. Open ArcMap toolboxes by clicking the ArcToolbox icon on the Standard toolbar.

   

3. Browse to the Slope tool by clicking the Spatial Analyst Tools toolbox, the Surface toolset, and then the Slope tool within it.

   

4. Drag the Slope tool into the model and place it to the right of the Elevation layer.

   

5. Using the Connect tool in the SuitabilityModel ModelBuilder model taskbar, connect the Elevation layer to the Slope tool. Make the connection by clicking the Elevation layer first, and then click the Slope tool. Click the Input raster option.

   

6. Double-click the Slope tool to open the tool's dialog box. On this dialog box, you can specify file names and additional parameters. Type Slope in the Output raster parameter to name the output slope raster. The model automatically saves the file into the Output.gdb geodatabase file. To summarize the input and output layers for the Slope tool, specify the parameters as follows:
   • Input raster: Elevation
   • Output raster: Slope

   

7. Click OK to close the Slope tool's dialog box.
8. Once the dialog box is closed, right-click the Slope tool and click Run to execute the tool.

   

9. Add the Slope output layer to the map document by right-clicking the green Slope layer in the model and clicking Add To Display.

   

10. Explore the Slope layer within the SuitabilityModeling map document. According to the legend of the Slope layer in the table of contents, steep slopes are displayed in red and flatter slopes are displayed in green.

    

Using the Euclidean Distance tool to derive data from base data (streams)

Next, a distance raster will be derived from the streams dataset to indicate how far the nearest stream is for each location. You will derive the distance raster from the Streams layer using the Euclidean Distance tool.

1. Click the ArcToolbox icon on the Standard toolbar. Browse to the Euclidean Distance tool in the Distance toolset in the Spatial Analyst Tools toolbox.

   

2. Add the Euclidean Distance tool to the model, placing it to the right of the Streams layer.

   

3. Using the Connect tool in the SuitabilityModeling model, connect the Streams layer to the Euclidean Distance tool. Make the connection by clicking the Streams layer first, and then click the Euclidean Distance tool. Choose the Input raster or feature source data option.

   

4. Double-click the Euclidean Distance tool to open the tool's dialog box. Type Distance_Streams into the Output distance raster parameter to name the output distance raster.
   • Input raster or feature source data: Streams
   • Output distance raster: Distance_Streams

   

5. Click OK to close the Euclidean Distance tool's dialog box.
6. Once the dialog box is closed, right-click the Euclidean Distance tool and click Run to execute the tool.

   

7. Add the output Distance_Streams layer to the map document by right-clicking the green output icon and clicking Add to Display.

   

8. Save the SuitabilityModel model by clicking the Save button in the ModelBuilder taskbar. Close the model once it is saved.
9. Turn on the Streams layer in the table of contents by checking the check box to the left of the Streams layer. Explore the Distance_Streams layer within the SuitabilityModeling map document by clicking various parts of the map with the Identify tool (found on the Tools toolbar).
10. Save the map document by clicking the Save button on the Standard toolbar.

At this point, you have derived data for the criteria for the bobcat Habitat submodel. From the Elevation layer, a slope raster was created to predict the presence of ledges, and a distance raster was derived from the Streams layer to find the dense cover near streams. Lesson 2: Transforming data onto a common scale covers how to transform base and derived data onto a common scale so that the three criteria can be combined. Once combined, the model can identify the preference of each location relative to habitat.