Summary: Cross operation
- The Cross operation performs an overlay of two raster maps by comparing pixels
at the same positions in both maps and keeping track of all the combinations of
values or classes/IDs that occur in both maps.
- The input maps of a Cross operation are raster maps, which have the same
georeference.
- The output cross-table lists the combinations of class names, identifiers or values
of the pixels in both maps. The number of pixels occurring for each combination of
classes/ID’s or values, from both maps, is counted. The area is obtained by
multiplying the number of pixels with the pixel area (square of the pixel size).
- The results are stored in an output cross-table and a cross-map. Both output objects
obtain an ID domain with the same name as the output cross-table. The ID domain
contains items, which are combinations of the class names, IDs, group names or
values of the first input map and those of the second input map.
A cross-table is often used in combination with Aggregation functions in the table
window.
- The cross-map is often less important because it contains too many different
combinations. The crossing operation is mostly done to obtain cover information of
one map with respect to another, and not so much to generate a new combination
map.