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 project
(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 Zealand
SOURCE CODE
Available at:
r.in.mat source code
(history)
Latest change: Wednesday Nov 27 22:53:26 2024 in commit: 3b5486c0463a7103ab2109e28bf860fe34539868
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GRASS Development Team,
GRASS GIS 8.5.0dev Reference Manual