Instructions provided describe how to change a particular value of a raster dataset to zero without changing the other values.
Often times, during spatial analysis using raster data, there might be a need to change a particular value in the data to different value to use the raster in the next analytical operation. For example, some values might need to be changed to zero.
ArcGIS offers a couple options to convert a particular value of a raster dataset to zero. One option is to use the Spatial Analyst Reclassify (reclass) tool to convert a particular value to zero. However, sometimes this might be cumbersome, if a raster has a large range of values. Hence, one has to go through each value (old value column) and look for the particular value in the list and then assign it as a zero (new value column).
A simpler option is to write a 'Con' statement in the Raster Calculator.
This document assumes that the Spatial Analyst Extension is turned on (for all versions) and that the Spatial Analyst toolbar is active (for versions 8.x and 9.x).
For ArcGIS versions 8.x and 9.x
Con([InRaster] == -9999, 0 , [InRaster])
Edit '-9999' to the particular value in the data to be changed to zero.
For ArcGIS version 10.0
Con("InRaster" == -9999, 0 , "InRaster")
Edit "-9999" to the particular value in data to be changed to zero.