Note: This document is for an older version of GRASS GIS that will be discontinued soon. You should upgrade, and read the current manual page.
NAME
r.cross - Creates a cross product of the category values from multiple raster map layers.
KEYWORDS
raster,
statistics
SYNOPSIS
r.cross
r.cross --help
r.cross [-z] input=string[,string,...] output=name [--overwrite] [--help] [--verbose] [--quiet] [--ui]
Flags:
- -z
- Non-NULL data only
- --overwrite
- Allow output files to overwrite existing files
- --help
- Print usage summary
- --verbose
- Verbose module output
- --quiet
- Quiet module output
- --ui
- Force launching GUI dialog
Parameters:
- input=string[,string,...] [required]
- Names of 2-30 input raster maps
- output=name [required]
- Name for output raster map
r.cross creates an
output raster map layer representing
all unique combinations of category values in the raster input layers
(
input=name,name,name, ...). At least two, but not more than
30,
input map layers must be specified. The user must also
specify a name to be assigned to the
output raster map layer
created by
r.cross.
With the -z flag NULL values are not crossed.
This means that if a NULL value occurs in any input data layer,
this combination is ignored,
even if other data layers contain non-NULL data.
In the example given below, use of the -z option
would cause 3 categories to be generated instead of 5.
If the -z flag is not specified, then map layer combinations
in which some values are NULL will be assigned
a unique category value in the resulting output map.
Category values in the new output map layer will be the
cross-product of the category values from these existing input map
layers.
For example, suppose that, using two raster map layers,
the following combinations occur:
map1 map2
___________
NULL 1
NULL 2
1 1
1 2
2 4
r.cross would produce a new raster map layer with 5 categories:
map1 map2 output
____________________
NULL 1 0
NULL 2 1
1 1 2
1 2 3
2 4 4
Note: The actual category value assigned to a particular combination
in the
result map layer is
dependent on the order in which the combinations occur in the input map
layer data and can be considered essentially random.
The example given here is illustrative only.
The category file created for the
output raster map
layer describes the
combinations of input map layer category values which generated
each category.
In the above example, the category labels would be:
category category
value label
______________________________
0 layer1(0) layer2(1)
1 layer1(0) layer2(2)
2 layer1(1) layer2(1)
3 layer1(1) layer2(2)
4 layer1(2) layer2(4)
A random color table is also generated for the
output map layer.
r.covar,
r.stats
Michael Shapiro, U.S. Army Construction Engineering Research Laboratory
SOURCE CODE
Available at:
r.cross source code
(history)
Latest change: Friday Dec 08 08:59:40 2023 in commit: 34835e620dd943349ebe7dc40b6d1b5c7ce94d63
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© 2003-2024
GRASS Development Team,
GRASS GIS 8.3.3dev Reference Manual