The user would then execute the GRASS program i.maxlik to actually create the final classified map.
All raster maps used to generate signature file can have semantic label set. Use r.support to set semantic labels of each member of the imagery group. Signatures generated for one scene are suitable for classification of other scenes as long as they consist of same raster bands (semantic labels match).
This map must be prepared by the user in advance using vector or raster digitizer. Of course other methods could be devised by the user for creating this training map - i.gensig makes no assumption about the origin of this map layer. It simply creates signatures for the classes defined in the training map for the image to be classified (the image is specified in other options - see below). The wxGUI vector digitizer can be used for interactively creating the training map.
This is the name of the group that contains the band files which comprise the image to be analyzed. The i.group command is used to construct groups of raster layers which comprise an image.
This names the subgroup within the group that selects a subset of the bands to be analyzed. The i.group command is also used to prepare this subgroup. The subgroup mechanism allows the user to select a subset of all the band files that form an image.
This is the resultant signature file (containing the means and covariance matrices) for each class in the training map that is associated with the band files in the subgroup select (see above). Resultant singature file can be used with any other imagery group as long as semantic labels match.
SIG file "lsat7_2000_gensig":
1 1 2 # 3 Semantic_label1 4 #water 5 4186 6 67.9508 48.7346 37.8915 15.3129 13.8473 12.0855 7 1.74334 8 0.439504 2.07267 9 0.662523 1.63501 4.21189 10 0.530339 2.40757 5.52857 22.433 11 0.561184 2.30762 5.18846 20.5364 20.4926 12 0.393218 1.2184 2.63628 9.61528 9.36025 5.85314
Available at: i.gensig source code (history)
Latest change: Sunday Feb 12 15:51:56 2023 in commit: 7d6ff54e985c1579e11b74c230cb8fa68a9aa928
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© 2003-2023 GRASS Development Team, GRASS GIS 8.3.dev Reference Manual