Knowledge Base - Technical Articles
HowTo: Merge rasters using ArcGIS Spatial Analyst
|Software:||ArcGIS - ArcEditor 8.1, 8.1.2 ArcGIS - ArcInfo 8.1, 8.1.2 ArcGIS - ArcView 8.1, 8.1.2|
Instructions provided describe how to merge rasters using ArcGIS Spatial Analyst's Raster Calculator. This method allows the combination of up to 23 rasters at a time.
Follow the steps below.
- Start ArcMap.
- Add all of the rasters to combine into the current document.
- Select Options from the Spatial Analyst dropdown menu.
- Switch to the Extent tab.
- Set the Analysis Extent dropdown list to 'Union of Inputs' and click OK.
- Select Raster Calculator from the Spatial Analyst dropdown list.
- Type 'MERGE(' in the expression box. Do not include the quotation marks.
- Double-click one of the rasters in the Layers list and add a comma after the raster's name in the expression box.
- Double-click the next raster in the Layers list and add a comma. Repeat until all rasters have been added.
- End the expression with a close parenthesis ')'.
Merge([Raster1], [Raster2], [Raster3], [Raster 4])Do not press return after entering the last parenthesis. The cursor must be to the right of it. Failure to do so causes the following error:
"Failed to evaluate the calculator equation"
- Click Evaluate.
The resulting raster appears with the name 'Calculation' in ArcMap. To make it a permanent dataset, right-click 'Calculation' and select 'Make Permanent'.
Last Modified: 12/14/2004
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