Hawth's Analysis Tools for ArcGIS
SPATIAL REPLACE TOOL
Input: a thematic (categorical) raster layer
Output: a new raster layer
- replaces cell values in a raster layer by assigning the closest permitted alternative value
- provides a method of removing unwanted categories from a raster layer by
assigning new values based on a simple neighborhood analysis, rather than a
- works on any size/shape of patch in the raster (i.e. works equally well for
linear classes like roads, pipelines or rivers as it does for large patches
like cutblocks, agricultural fields, etc)
- allows the user to interactively define the set of acceptable replacement values
- processes only one band of the raster
- replaces only one value at a time (to replace multiple values, the tool
would have to be run once per value)
[Click for larger view]
A raster layer must be loaded into ArcMap in order to use this
tool. If you wish to run this tool on a multi-band image, you must load
the bands into ArcMap separately, and run the tool on each one.
Priority of replacement values.
This tool begins by examining the 8 cells immediately surrounding the cell
that is being spatially recoded. If there are any acceptable replacement values
among these 8 cells, it will select the lowest value (even if another higher value is in
majority). If there are no suitable replacement values in these 8 cells, the tool moves
out by one cell, and so on, until an acceptable replacement is found.