CommunityViz: Advanced Suitability Analysis

If you have taken our Basic CommunityViz Suitability Analysis course or have a familiarity with CommunityViz, this course is designed to give you more advanced techniques for determining suitability. These mini-tutorials are best taken in order but can viewed independently. Topics include unioning layers in Model Builder, writing formulas in CommunityViz, updating the Suitability Wizard, and performing raster analysis using ArcGIS Spatial Analyst.

Wildlife layers, created in the Basic Suitability course,  can be unioned together in ArcGIS.  It is helpful to add a field to each layer to simplify the factor weighting. Open Model Builder in ArcGIS and add Union tools twice with the three wildlife areas.  Link the layers and the tools together.  Set the output locations for the results.  Run the model. Symbolize results by factor. Add a field and calculate the combined score. Review Union combined score.

Create a custom formula for the Ranch layer based on weighted overlap of unioned wildlife layer.  Open Attribute in 360Setup tab.  Add new attribute and write formula for OverlapWeightedAvg for Wildlife Combined score.  Check results by symbolizing wildlife score in Ranch layer.

Review soils attributes to find floodplain (stand-in for hay meadows) and grazing productivity.  Create new attribute using Formula Wizard to assign value depending on conditions.  If then else statement created automatically. Review ranch score in Soils layer.  Upload to Ranch layer using overlap weighted average formula. Symbolize Ranch layer to check results.

Create a new more advanced suitability analysis called Conservation2. Add ranching value using the uploaded attribute and wildlife using the wildlife attribute. For Viewshed, use the viewshed grid.  Measure Proximity to road.  Measure parcel land area using shape area.  Review the results by symbolizing Conservation2.  Revise weighting factors.  Review attribute table for normalize values. 

The CommunityViz Suitability analysis used a viewshed analysis for evaluating scenic values. To create a viewshed analysis, load a DEM (digital elevation model) and potential viewpoints (e.g. regular intervals along a road). The ArcGIS Spatial Analyst toolbox includes  Viewshed(in Surface).  After completing the  dialogue box, set the Output Coordinates in Environments. Review the Viewshed results by symbolizing the values.

Suitability using grid in ArcGIS Spatial Analyst.  Create a score for the soils polygon layer’s ranching value based on haymeadows and grazing productivity.  Convert the soils Polygon to Raster using this ranchscore value.  Set the Environments for coordinates, extent and Cell Size in Raster Analysis.  Review results of ranch grid by stretching colors with shades of orange.  Properties shows cell size as 39, 39 rather than 30, 30.  Rerun analysis to get 30 meter cell size matching the viewshed size. 

Converting a raster image (Viewshed) to a polygon requires that the grid contain integer values.  Use the Raster Calculator’s INT(viewshed) command removes any decimal places.  Convert Viewshed raster grid to polygon.  Symbolize the polygon legend with zero width of outlines and quantities for the gridcode.  

Suitability using grid in ArcGIS Spatial Analyst.  Create a score for the soils polygon layer’s ranching value based on haymeadows and grazing productivity.  Convert the soils Polygon to Raster using this ranchscore value.  Set the Environments for coordinates, extent and Cell Size in Raster Analysis.  Review results of ranch grid by stretching colors with shades of orange.  Properties shows cell size as 39, 39 rather than 30, 30.  Rerun analysis to get 30 meter cell size matching the viewshed size. 

Convert the Wildlife layer from polygon to raster.  Uses combine attribute, set grid size and make extent same as viewshed.  Use Identify to find NoData areas.

Add viewshed, ranch and wildlife together in Raster Calculator to create raster suitability analysis.  Review results with symbology with darker shades for highest scores.  Discussion of the limitations of raster analysis.