The Mask button can be used with any raster, mosaic, or image service layer to create a hidden or masked area within the dataset. The masked area can be defined by the following:
- The data view extents
- A selected polygon graphic
- A selected polygon feature within a feature class layer
The masked area will appear transparent in the temporary layer.
- To view the Image Analysis window in ArcMap, click Windows on the Main menu and click Image Analysis.
- Click a layer in the Image Analysis window.
- Optionally, select a polygon feature within a feature class layer or select a polygon graphic.
- Click the Mask button
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The masked output is added as a temporary raster layer to the table of contents. By default, the masked area is the area defined by the display view extents; otherwise, it is clipped to the selected feature or graphic.
The Mask operation adds the Clip function to the raster layer.