1r.in.mat(1) Grass User's Manual r.in.mat(1)
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6 r.in.mat - Import a binary MAT-File(v4) to a GRASS raster.
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9 raster
10
12 r.in.mat
13 r.in.mat help
14 r.in.mat [-v] input=string [output=string] [--overwrite]
15 Flags:
17 -v Verbose mode
18 --overwrite
20 Parameters:
22 input=string
23 Name of an existing MAT-File(v4)
24 output=string
26 Name for the output raster map (override)
27
29 r.in.mat will import a GRASS raster map from a Version 4 MAT-File which
30 was created with Matlab or Octave. Attributes such as map title and
31 bounds will also be imported if they exist.
32 Specifically, the following array variables will be read:
33 map_data
35 map_name
37 map_title
39 map_northern_edge
41 map_southern_edge
43 map_eastern_edge
45 map_western_edge
47 Any other variables in the MAT-file will be simply skipped over.
48 The 'map_name' variable is optional, if it exists, and is valid, the
49 new map will be thus named. If it doesn't exist or a name is specified
50 with the output= option, the raster map's name will be set to "MatFile"
51 or the name specified respectively. (maximum 64 characters; normal
52 GRASS naming rules apply)
53 The 'map_title' variable is optional, the map's title is set if it
54 exists.
55 The 'map_northern_edge' and like variables are mandatory unless the
56 user is importing to a "XY" non-georeferenced location (e.g. imagery
57 data). Latitude and longitude values should be in decimal form.
58
60 r.in.mat imports a Version 4 MAT-File. These files can be successfully
61 created with more modern versions of Matlab and Octave (see "EXAMPLES"
62 below).
63 Everything should be Endian safe, so the file to be imported can be
64 simply copied between different system architectures without binary
65 translation (caveat: see "TODO" below).
66 As there is no IEEE value for NaN in integer arrays, GRASS's null value
67 may be used to represent it within these maps. Usually Matlab will save
68 any integer based matrix with NaN values as a double-precision floating
69 point array, so this usually isn't an issue. To save space, once the
70 map is loaded into GRASS you can convert it back to an integer map with
71 the following command:
72 r.mapcalc int_map="int(MATFile_map)"
73 NaN values in either floating point or double-precision floating point
74 matrices should translate into null values as expected.
75 r.in.mat must load the entire map array into memory before writing,
76 therefore it might have problems with huge arrays. (a 3000x4000 DCELL
77 map uses about 100mb RAM)
78 GRASS defines its map bounds at the outer-edge of the bounding cells,
79 not at the coordinates of their centroids. Thus, the following Matlab
80 commands may be used to determine and check the map's resolution infor‐
81 mation will be correct:
82 [rows cols] = size(map_data)
83 x_range = map_eastern_edge - map_western_edge
84 y_range = map_northern_edge - map_southern_edge
85 ns_res = y_range/rows
86 ew_res = x_range/cols
87 Remember Matlab arrays are referenced as (row,column), i.e. (y,x).
89 In addition, r.in.mat and r.out.mat make for a nice binary container
90 format for transferring georeferenced maps around, even if you don't
91 use Matlab or Octave.
92
94 In Matlab, save with:
95 save filename.mat map_* -v4
96 In Octave, save with:
97 save -mat4-binary filename.mat map_*
98
101 Robust support for mixed-Endian importation. (This is a work in
102 progress, please help by reporting any failures to the GRASS bug track‐
103 ing system)
104 Add support for importing map history, category information, color map,
105 etc. if they exist.
106 Option to import a version 5 MAT-File, with map and support information
107 stored in a single structured array.
108
110 If you encounter any problems, please contact the GRASS Development
111 Team.
112
114 r.out.mat, r.in.ascii, r.in.bin, r.mapcalc, r.null.
115 The Octave project
117
119 Hamish Bowman
120 Department of Marine Science
122 University of Otago
123 New Zealand
124 Last changed: $Date: 2006/04/21 09:06:24 $
126 Full index
128GRASS 6.2.2 r.in.mat(1)