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Extensions > Spatial Analyst > Spatial Analyst functional reference > Generalization (Spatial Analyst)
Extensions > Spatial Analyst > Spatial Analyst functional reference > Generalization (Spatial Analyst)
An overview of the Generalization tools |
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Release 9.2
Last modified January 3, 2008 |
Print all topics in : "Generalization (Spatial Analyst)" |
Sometimes a raster dataset contains data that is erroneous or irrelevant to the analysis at hand or is more detailed than you need. For instance, if a raster dataset was derived from the classification of a satellite image, it may contain many small and isolated areas that are misclassified. The generalization tools help you identify such areas and automate the assignment of more reliable values to the cells that make up the areas.
Learn more about understanding generalization analysis Learn about creating individual zones: Region Group Learn about working on zones Learn about smoothing zone edges Learn about altering the resolution Learn about generalization analysis sample applications
The generalization tools are divided into three categories:
- Those that work on zones (Region Group, Nibble, Shrink, Expand, and Thin)
- Those that work on zone edges (Boundary Clean and Majority Filter)
- Those that alter the resolution of the data (Aggregate)
The following table lists the available generalization tools, provides a brief description of each, and identifies if the tool works in ArcToolbox, Map Algebra, or ArcObjects.
| Tool | Description | ArcToolbox | Map Algebra | ArcObjects |
| Aggregate | Generates a reduced-resolution version of a raster in which each output cell contains the SUM, MIN, MAX, MEAN, or MEDIAN of the input cells that are encompassed by the extent of the output cell. | X | X | X |
| Boundary Clean | Smoothes the boundary between zones by expanding and shrinking the boundary. | X | X | X |
| Expand | Expands the selected zones by a specified number of cells. | X | X | X |
| Majority Filter | Replaces cells in a grid based on the majority of their contiguous neighboring cells. | X | X | X |
| Nibble | Replaces areas in a grid corresponding to a mask with the values of the nearest neighbors. | X | X | X |
| Region Group | Records, for each cell in the output, the identity of the connected region to which it belongs within the Analysis window. A unique number is assigned to each region. | X | X | X |
| Shrink | Shrinks the selected zones by a specified number of cells. | X | X | X |
| Thin | Thins linear features in a raster. | X | X | X |