#3680: [PATCH] r.object.geometry: add output of mean coordinates of objects - difference to r.mapcalc/r.univar output ------------------------------------------------+------------------------- Reporter: mlennert | Owner: grass-dev@… Type: enhancement | Status: new Priority: normal | Milestone: Component: Addons | Version: unspecified Keywords: r.object.geometry cell coordinates | CPU: Unspecified Platform: Unspecified | ------------------------------------------------+------------------------- For some applications it can be useful to obtain the mean coordinates of raster objects. I would like to add this functionality to r.object.geometry. For this I use the attached patch.
However, when I use this to calculate mean coordinates of objects, I get one unit of resolution difference between these results and the results of the following r.mapcalc/r.univar call: {{{ g.region rast=MyMap r.mapcalc "x = x()" r.univar -t x zones=MyMap }}} Here's some output for comparison: {{{ r.mapcalc/r.univar r.object.geometry zone|mean cat|mean_x 1|270347.103514056 1|270347.353514 2|270355.499712833 2|270355.749713 3|270243.128030303 3|270243.378030 4|270270.053380443 4|270270.303380 5|270280.90239726 5|270281.152397 6|270277.778301887 6|270278.028302 }}} The result of r.object.geometry is always shifted one resolution (0.25) to the East. However, y values are not: {{{ r.mapcalc/r.univar r.object.geometry zone|mean cat|mean_x 1|154056.164959839 1|154056.164960 2|153996.903084224 2|153996.903084 3|154041.199242424 3|154041.199242 4|154016.742456073 4|154016.742456 5|154017.476598174 5|154017.476598 6|154017.057193396 6|154017.057193 }}} Is the error in my patch, or maybe in the r.mapcalc x() function ? Any objections to applying this patch ? It changes the output of the module, but it add the additional values at the end, so unless some scripts rely on fd being the last value, this should not cause too much trouble. Moritz -- Ticket URL: <https://trac.osgeo.org/grass/ticket/3680> GRASS GIS <https://grass.osgeo.org>
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