Suitability modeling workflow using ArcGIS Pro—Lesson 3: Weighting and combining data

In lessons 1 and 2, you derived and transformed criteria for the Habitat submodel onto a common scale. In this lesson, you will weight and combine the transformed criteria into a single surface depicting the suitability for the Habitat submodel. You will also weight and combine the three submodels (Habitat, Food, and Security) into the final suitability surface.

This lesson is divided into three sections:

1. Opening and editing the ModelBuilder model
2. Using the Weighted Sum tool to weight and combine transformed criteria
3. Using the Weighted Sum tool to weight and combine submodels

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

This lesson continues on the data that you downloaded in lesson 1. If you have not downloaded the data, see the first section in Lesson 1: Exploring and deriving data.

Opening and editing the ModelBuilder model

1. If the Suitabililty Modeling project was closed after lesson 2, reopen it by double-clicking the SuitabilityModeling.aprx file in the SuitabilityModeling folder.

   

2. Open the SuitabilityModel model that you began building in lessons 1 and 2 by right-clicking the model and clicking Edit.

   

Using the Weighted Sum tool to weight and combine transformed criteria

The Weighted Sum tool will be used to combine the transformed criteria in the Habitat submodel into a single surface.

1. Open the Geoprocessing pane on the ModelBuilder tab by clicking the Tools icon in the taskbar at the top of the map document.

   

2. Click Toolboxes at the top of the Geoprocessing pane. Browse to the Weighted Sum tool by clicking the Spatial Analyst Tools toolbox and the Overlay toolset within it.

   

3. Drag the Weighted Sum tool into the model and place it to the right of the transformed criteria layers.

   

4. Double-click the Weighted Sum tool icon in the SuitabilityModel model to open the tool's dialog box. From the drop-down list next to the Input raster parameter (the circle with the drop-down arrow), choose the three transformed datasets from the Model Variables list. Enter the weights for each transformed dataset as specified below. Type HabitatSubmodel in the Output raster parameter. This dataset is automatically saved into the Output.gdb geodatabase. To summarize the parameters of the Weighted Sum tool, specify the parameters as follows:
   • Input rasters: Transformed_LandUse:2, Transformed_Slope:2, Transformed_DistanceStreams:2
   • Output raster: HabitatSubmodel
   • Weights: Transformed_LandUse (2), Transformed_Slope (1), Transformed_DistanceStreams (1)

   

5. Click OK to apply the changes and close the Weighted Sum tool's dialog box.
6. Right-click the Weighted Sum tool and click Run to execute the tool.

   

7. Right-click the output HabitatSubmodel layer (green) and click Add To Display to add the output HabitatSubmodel layer to the map document.

   

8. Click the Map tab to view the map document. Change the symbology of the HabitatSubmodel layer by clicking the Symbology icon on the Appearance tab on the taskbar.

   

9. Choose a Stretch symbology. Choose a red-to-green color scheme from the Color scheme drop-down list.

   

10. Visually inspect the HabitatSubmodel layer. The areas in green indicate suitable habitat as a factor of land use, slope, and distance from streams criteria.

Using the Weighted Sum tool to weight and combine submodels

From the Data.gdb geodatabase in the SuitabilityModeling folder, add the FoodSubmodel and SecuritySubmodel layers to the Contents pane.

1. Access the Data.gdb geodatabase by first clicking the Project icon on the View tab on the ArcGIS Pro taskbar.

   

2. In the Project pane, browse to the Data.gdb geodatabase in the SuitabilityModeling folder connection. Open the Data.gdb geodatabase by clicking the arrow to the left of the geodatabase.

   

3. Drag the FoodSubmodel and SecuritySubmodel layers from the Data.gdb geodatabase into the Contents pane.

   

4. Click the Map tab to view the map document. Change the symbology of the FoodSubmodel layer by clicking the Symbology icon on the Appearance tab on the taskbar.

   

5. Choose a Stretch symbology, and choose a red-to-green color scheme from the Color scheme drop-down list.

   

6. Visually inspect the FoodSubmodel layer. The areas in green indicate suitable areas for finding prey as a factor of land use and distance from wetlands.

   

7. Next, change the symbology of the SecuritySubmodel to compare it to the Food and Habitat submodels. Turn off the FoodSubmodel layer by unchecking the check box next to it in the Contents pane. Click the Map tab to view the map document. Change the symbology of the SecuritySubmodel layer by clicking the Symbology icon on the Appearance tab on the taskbar.

   

8. Choose a Stretch symbology, and choose a red-to-green color scheme from the Color scheme drop-down list.

   

9. Visually inspect the SecuritySubmodel layer. The areas in green indicate safer areas that are farther away from roads and buildings.

   

10. Click the SuitabilityModel tab and add the FoodSubmodel and SecuritySubmodel layers into the SuitabilityModel model, placing them in line with the Habitat submodel.

    

11. The Weighted Sum tool will be used again to combine the three submodels into the final suitability surface. Open the Geoprocessing pane on the ModelBuilder tab by clicking the Tools icon in the taskbar at the top of the map document.

    

12. Browse to the Weighted Sum tool by clicking the Spatial Analyst Tools toolbox and the Overlay toolset within it.

    

13. Drag the Weighted Sum tool into the SuitabilityModel model and place it to the right of the three submodels.

    

14. Double-click the Weighted Sum tool icon in the SuitabilityModel model to open the tool's dialog box. From the drop-down list next to the Input raster parameter (the circle with the drop-down arrow), enter the three submodels in the Input rasters parameter by choosing them from the Model Variables in the drop-down list. Specify the weights for each submodel as identified below. Type FinalSuitability in the Output raster parameter to name the output suitability raster. To summarize the parameters for the Weighted Sum tool, specify the parameters as follows:
    • Input rasters: FoodSubmodel:2, HabitatSubmodel:2, SecuritySubmodel:2
    • Output raster: FinalSuitability
    • Weights: FoodSubmodel (1.5), HabitatSubmodel (1), SecuritySubmodel (1.5)

    

15. Click OK to apply the changes and close the Weighted Sum tool's dialog box.
16. Right-click the tool and click Run to execute the second Weighted Sum tool.

    

17. Right-click the output FinalSuitability layer (green) and click Add To Display to add the output FinalSuitability layer to the map document.

    

18. Save the SuitabilityModel model by clicking the Save button in the ModelBuilder taskbar. Click the Map tab to browse away from the SuitabilityModel model after the model has been saved.

    

19. Change the symbology of the FinalSuitability layer by clicking the Symbology icon on the Appearance tab on the taskbar.

    

20. Choose a Stretch symbology, and choose a red-to-green color scheme from the Color scheme drop-down list. The green color indicates suitable locations, whereas the red indicates poor locations.

    

21. Visually inspect the FinalSuitability surface. The areas in green indicate overall suitable habitat as a factor of the Food, Habitat, and Security submodels.

    

22. Save the map document by clicking the Save button in the taskbar.

    

At this point, you have weighted the submodels relative to one another and combined them into a final suitability surface. In Lesson 4: Locating and connecting regions, you will locate and connect the most suitable regions of habitat.