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.in.mat  - Imports a binary MAT-File(v4) to a GRASS raster.
KEYWORDS
raster, 
import
SYNOPSIS
r.in.mat
r.in.mat --help
r.in.mat input=name  [output=name]   [--overwrite]  [--help]  [--verbose]  [--quiet]  [--ui] 
Flags:
- --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=name [required]
 
- Name of input MAT-File(v4)
 
- output=name
 
- Name for output raster map (override)
 
 
r.in.mat will import a GRASS raster map from a Version 4 MAT-File 
which was created with Matlab or Octave.
Attributes such as map title and bounds will also be imported if they exist.
Specifically, the following array variables will be read:
  -  map_data
  
 -  map_name
  
 -  map_title
  
 -  map_northern_edge
  
 -  map_southern_edge
  
 -  map_eastern_edge
  
 -  map_western_edge
 
Any other variables in the MAT-file will be simply skipped over.
The '
map_name' variable is optional, if it exists, and is valid, the 
new map will be thus named. If it doesn't exist or a name is specified with
the 
output= option, the raster map's name will be set to 
"
MatFile" or the name specified respectively.
(maximum 64 characters; normal GRASS naming rules apply)
The '
map_title' variable is optional, the map's title is set if it 
exists.
The '
map_northern_edge' and like variables are mandatory unless the 
user is importing to a "XY" non-georeferenced location
(e.g. imagery data). Latitude and longitude values should be in decimal form.
r.in.mat imports a Version 4 MAT-File. These files can be 
successfully created with more modern versions of Matlab and Octave
(see "EXAMPLES" below).
Everything should be Endian safe, so the file to be imported can be simply 
copied between different system architectures without binary translation
(caveat: see "TODO" below).
As there is no IEEE value for 
NaN in integer arrays, GRASS's null 
value may be used to represent it within these maps. Usually Matlab will save 
any integer based matrix with 
NaN values as a double-precision 
floating point array, so this usually isn't an issue. To save space, once the 
map is loaded into GRASS you can convert it back to an integer map with the 
following command:
r.mapcalc "int_map = int(MATFile_map)"
 
NaN values in either floating point or double-precision floating point
matrices should translate into null values as expected.
r.in.mat must load the entire map array into memory before writing,
therefore it might have problems with 
huge arrays.
(a 3000x4000 DCELL map uses about 100mb RAM)
GRASS defines its map bounds at the outer-edge of the bounding cells, not at
the coordinates of their centroids. Thus, the following Matlab commands may 
be used to determine and check the map's resolution information will be correct:
    [rows cols] = size(map_data)
    x_range = map_eastern_edge - map_western_edge
    y_range = map_northern_edge - map_southern_edge
    ns_res = y_range/rows
    ew_res = x_range/cols
 
Remember Matlab arrays are referenced as 
(row,column),
i.e. 
(y,x).
In addition, 
r.in.mat and 
r.out.mat make for a nice 
binary container format for transferring georeferenced maps around, 
even if you don't use Matlab or Octave. 
In Matlab, save with:
save filename.mat map_* -v4
In Octave, save with:
save -mat4-binary filename.mat map_*
 
Robust support for mixed-Endian importation.
(This is a work in progress, please help by reporting any failures to the
GRASS bug tracking system;
Add support for importing map history, category information, color map, etc.
if they exist.
Option to import a version 5 MAT-File, with map and support information 
stored in a single structured array.
If you encounter any problems, please contact the GRASS Development Team.
r.out.mat,
r.in.ascii, 
r.in.bin,
r.mapcalc,
r.null.
The Octave project
Hamish Bowman 
Department of Marine Science
University of Otago
New ZealandSOURCE CODE
  Available at:
  r.in.mat source code
  (history)
  Latest change: Thursday Feb 03 11:10:06 2022 in commit: 547ff44e6aecfb4c9cbf6a4717fc14e521bec0be
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.
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GRASS Development Team,
GRASS GIS 8.2.2dev Reference Manual