In ArcGIS, why do the results of analysis not cover the desired spatial extent?

After performing a raster analysis using the Spatial Analyst extension (toolbar) in ArcGIS, you may notice that the spatial extent of the raster output (cost surface) does not fully reach the desired extent. To correct this, adjust the setting that controls the spatial extent for subsequent operations, so it is set to a particular dataset or specific spatial extent. The raster output will then fully extend to the boundary you need.

To change the analysis extent using the Spatial Analyst extension:

1. From the Spatial Analyst extension drop-down menu, select Options.
   
   
2. Click the Extent tab. To change the analysis extent to the desired dataset boundary, select Same as Layer "xxxxx". You may also choose to manually enter coordinate points for the analysis extent by selecting As Specified Below. If you select Same as Display, you will set the analysis extent to the same spatial extent currently appearing in the Data Frame window of ArcMap.

   Note: By default, the analysis extent is set to Intersection of Inputs, which constrains the analysis results to the input dataset with the smallest spatial extent.

3. Click OK, and then redo the raster analysis. Your raster output will now include all cell values in your area of interest.

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