Hello Carlos, Maybe it has something to do with the pixel resolution? I would certainly expect the same results, but with a very similar region (i.e. same number of rows and columns, or at least very close and a similar number of pixels)
Maybe when projecting the raster, the length of the array is varying but I wouldn't expect to vary very much, are you getting the same results in a previous version of GRASS? (7.0 or even 6.4?) Greetings El nov. 16, 2015 11:35 AM, "Carlos Grohmann" <[email protected]> escribió: > Hi all. > > I'm analyzing some global-scale DEMs, like ETOPO1/2, SRTM30_PLUS, etc. > > I'm getting the statistics for the whole dataset with r.univar, but today > I noticed that the results differ if I use different projections. (GRASS > 7.1) > > For example, ETOPO2: > > Using a latlong pseudo-projection (plate carré) > > > min: -10791 > max: 8440 > mean: -1888.6480792 > median: -2457 > stddev: 2650.01922839 > p25: -4273 > p75: 216 > > > And using equal-area cylindrical: > > min: -10791 > max: 8440 > mean: -2379.78247747 > median: -3291 > stddev: 2507.89668617 > p25: -4541 > p75: 94 > > > > Are these differences expected? I would think that they should be the > same, regardless of projection (I'm thinking on the elevation values as an > array of values). > > thanks > > Carlos > > > > > > -- > Prof. Carlos Henrique Grohmann > Institute of Energy and Environment - Univ. of São Paulo, Brazil > - Digital Terrain Analysis | GIS | Remote Sensing - > > http://carlosgrohmann.com > http://orcid.org/0000-0001-5073-5572 > ________________ > Can’t stop the signal. > > _______________________________________________ > grass-user mailing list > [email protected] > http://lists.osgeo.org/mailman/listinfo/grass-user >
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