Marcello Gorini wrote: > I use r.mapcalc to create maps that serve as counters such as > the command i++ in C.
Raster maps aren't supposed to be modified in-place; that applies to all raster commands, not just r.mapcalc. At the moment, you will usually get away with it, because: 1. the actual raster data is written to a temporary file, which replaces the original file when the map is closed, and 2. the support files (cellhd, categories, colour table, etc) are normally opened, read into (or written from) memory, then closed, rather than being held open. However: you won't necessarily get away with it if you're using GDAL-linked maps (r.external, r.external.out), as those are likely to be overwritten in place. If we eventually change the raster format in 7.x, there's a chance that older formats will be supported by this mechanism. Even if we support multiple versions natively, fixing issues with concurrent access is on the agenda, and that may end up breaking in-place modification. IOW, when I say that in-place modification is "not guaranteed" to work, I mean that there are reasons to suspect that it may actually fail in specific cases now, and in the general case in the future. -- Glynn Clements <[email protected]> _______________________________________________ grass-user mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/grass-user
