On Sat, Feb 25, 2012 at 7:52 PM, Michael Barton <[email protected]> wrote: > The trick for many things in GRASS is to "think raster" instead of thinking > vector. > > Make a raster DEM from your map (if you don't already have one). > > Query the raster (e.g., with r.mapcalc or r.reclass) to create a raster of > elevations between your contour lines (e.g., in r.reclass the specification > 1000 thru 1500 = 1).
Nice solution! To do that for the full map with r.mapcalc and steps of 500 m, try r.mapcalc "elevation.reclass = if(elevation < 0, (int(elevation / 500) - 1) * 500, int(elevation / 500) * 500)" followed by: > > Run r.to.vect on the queried map to turn it into an area. > > Michael Markus M > > > > On Feb 25, 2012, at 10:00 AM, <[email protected]> > <[email protected]> wrote: > >> Date: Sat, 25 Feb 2012 10:42:20 +0200 >> From: Maris Nartiss <[email protected]> >> Subject: Re: [GRASS-user] How to create polygon from two selected >> contour line >> To: Paolo Cavallini <[email protected]> >> Cc: [email protected] >> Message-ID: >> <CAK8GbeCR-5p7QnTp6cQDLT16pZ=ymbrdsqpat73d+czbvwq...@mail.gmail.com> >> Content-Type: text/plain; charset=UTF-8 >> >> Convert line type from line to boundary (v.type) >> Digitize a pair of new boundaries between both contour lines to form a >> enclosed area or use v.hull to get an outline for merging in (v.patch) >> Add a centroid (digitize or v.centroids) to enclosed area. >> Profit! >> >> Not the mos easy way, still possible. >> >> Maris. >> >> 2012/2/25 Paolo Cavallini <[email protected]>: >>> Il 25/02/2012 08:45, SWAPAN GHOSH ha scritto: >>> >>>> Hello Grassuser, >>>> Anybody can please help me " To create polygon from two selected contour >>>> line " using grass comand.......... >>> >>> I'm afraid I can't - I tried recently, no joy. >>> Good luck, if you succeed please let us know. >>> All the best. >>> >>> -- >>> Paolo Cavallini >>> See: http://www.faunalia.it/pc >>> >>> _______________________________________________ >>> grass-user mailing list >>> [email protected] >>> http://lists.osgeo.org/mailman/listinfo/grass-user >> > > _____________________ > C. Michael Barton > Visiting Scientist, Integrated Science Program > National Center for Atmospheric Research & > University Consortium for Atmospheric Research > 303-497-2889 (voice) > > Director, Center for Social Dynamics & Complexity > Professor of Anthropology, School of Human Evolution & Social Change > Arizona State University > www: http://www.public.asu.edu/~cmbarton, http://csdc.asu.edu > > > > > > _______________________________________________ > grass-user mailing list > [email protected] > http://lists.osgeo.org/mailman/listinfo/grass-user _______________________________________________ grass-user mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/grass-user
