Ubuntu Manpage: r.in.mat - Imports a binary MAT-File(v4) to a GRASS raster.

Provided by: grass-doc_7.8.2-1build3_all

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)

DESCRIPTION

       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.

NOTES

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.

EXAMPLES

       In Matlab, save with:
       save filename.mat map_* -v4
       In Octave, save with:
       save -mat4-binary filename.mat map_*

TODO

       Robust  support  for mixed-Endian importation.  (This is a work in progress, please help by reporting any
       failures to the GRASS bug tracking system; you will need to login with an OSGeo Userid)
       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.

KNOWN ISSUES

       If you encounter any problems, please contact the GRASS Development Team.

AUTHOR

       Hamish Bowman
        Department of Marine Science
       University of Otago
       New Zealand

SOURCE CODE

       Available at: r.in.mat source code (history)

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