Extract optimal sites with the Con tool
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You’ll use a conditional expression in the Con tool to extract only the optimal sites. It has been decided that those sites that are considered optimal must have a suitability value of 9 (the highest value in the suit_areas output). In the conditional expression, all areas with a value of 9 will retain their original value (9). Areas with a value of less than 9 will be changed to NoData.
To use the Con tool, expand the Spatial Analyst Tools toolbox and expand the Conditional toolset. Click the Con tool and drag it onto the ModelBuilder window. An element that references the Con tool will be created in the display window. Right-click the Con tool element and click Open.
Click the Input conditional raster drop-down arrow and click the Suitable Areas variable. Click the Input true raster or constant value drop-down arrow and click the Suitable Areas variable.
If the condition you enter is true of the cells in the Input conditional raster, the value of the cells of the Input true raster or constant value will be applied to the cells of the output raster.
Leave the value for the Input false raster or constant value parameter blank. The default will be applied—any value in the Input conditional raster that doesn’t meet the condition you enter will be assigned NoData in the output raster.
Accept the default path for the Output raster parameter value, but change the default name to “opt_areas”.
Type the condition “Value = 9” for the value of the Expression parameter. If a cell value in the conditional raster (Suitable Areas) is 9, it will retain its original value (9) in the result. If a cell value is not 9, it will be changed to NoData. This way, you will exclude all areas except those most suitable for locating the school.
Type “Output optimal areas raster” in the Enter new element name text box and click OK on the Rename dialog box.
Right-click the Output optimal areas raster derived data element and click Add To Display.
Right-click the Con tool element and click Run to run the process.
Examine the layer added to your ArcMap display. These are the optimal site locations for the new school.