How To: Insert a subset grid into a base grid


Instructions provided describe how to insert a subset grid into a base grid. It may be necessary to insert a smaller portion, or subset, of one grid into a larger, base grid. Functionality found in the Spatial Analyst 'Merge' command can perform this operation.


Follow the steps below.

  1. Start ArcMap and add the base and subset grids to the data frame.
  2. Activate the Spatial Analyst toolbar, if not already active, and select 'Spatial Analyst > Options.'
  3. Click the 'Extent' tab.
  4. Set the Analysis Extent to 'Same as layer "<Base grid>".'
  5. Click 'OK' to close the 'Options' dialog.
  6. Select, on the Spatial Analyst toolbar, 'Spatial Analyst > Raster Calculator.'
  7. Use the 'Merge' command in the Raster Calculator. Specify the subset grid first. This is an example of the syntax:

    MERGE ([subset],[base])

  8. Click 'Evaluate' and then analyze the output 'Calculation' layer for quality. If the layer is correct, right-click it and select 'Make Permanent.' Save the grid to a permanent storage location.

    For a complete description of how the 'Merge' command works, refer to the Spatial Analyst Functional Reference from the Desktop help.