[GRASS-user] Re: r.grow: Manual Page Needs Additional Information
On 26/04/2012 10:05, Markus Neteler wrote: On Tue, Apr 24, 2012 at 6:40 PM, Rich Shepardrshep...@appl-ecosys.com wrote: I've just been made aware of the r.grow module as part of the solution to the map mis-match issue with r.stream.extract. The r.grow manual page is quite clear on how to use it, but is missing important information: when and why one should apply this module to a raster map. If anyone has the answer, please send me a text snipped for inclusion into the manual. I am not sure if there is a single answer to when and why one should use r.grow. I use it before generating area statistics with r.stats, e.g.: r.stats -c admin_units,land_cover outfile Administrative boundaries are usually only defined on land, they do not cover areas which in the land cover map appear as coastal lagoons, tidal flats, and similar. So I grow the admin_units map sufficiently, before running r.stats. Hermann ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
[GRASS-user] Re: r.grow: Manual Page Needs Additional Information
On Fri, 27 Apr 2012, Hermann Peifer wrote: I am not sure if there is a single answer to when and why one should use r.grow. I use it before generating area statistics with r.stats, e.g.: r.stats -c admin_units,land_cover outfile Administrative boundaries are usually only defined on land, they do not cover areas which in the land cover map appear as coastal lagoons, tidal flats, and similar. So I grow the admin_units map sufficiently, before running r.stats. Hermann, Single answers not required. :-) Your use is a valid example of when and why r.grow should be applied. A collection of such examples (on the wiki with references from the manual page?) would be highly valuable for everyone. Thank you, Rich ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
Re: [GRASS-user] Re: r.grow: Manual Page Needs Additional Information
On 27/04/12 15:24, Rich Shepard wrote: On Fri, 27 Apr 2012, Hermann Peifer wrote: I am not sure if there is a single answer to when and why one should use r.grow. I use it before generating area statistics with r.stats, e.g.: r.stats -c admin_units,land_cover outfile Administrative boundaries are usually only defined on land, they do not cover areas which in the land cover map appear as coastal lagoons, tidal flats, and similar. So I grow the admin_units map sufficiently, before running r.stats. Hermann, Single answers not required. :-) Your use is a valid example of when and why r.grow should be applied. A collection of such examples (on the wiki with references from the manual page?) would be highly valuable for everyone. Another example I've come across in an exercice for students: they have to build a dam and then use r.lake to see which area is filled. They build the dam by drawing a vector line with v.digit, then transforming it to raster with v.to.rast and adding it to the DEM with r.mapcalc. But since a single vector line is only one pixel wide, water often gets through the dam it is a diagonal line. r.grow'ing the line by a few pixels helps consolidate the dam instead of flooding the entire South-West Wake county ;-) Moritz ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
