<div dir="ltr">Ok, sorry about the incomplete post.<div><br></div><div>I reprojected from a latlong location to a cylindrical equal area projection, using the default nearest neighbor resampling method.</div><div><br></div><div>original location:</div><div><div>>GRASS 7.1.svn (base_maps):~ > g.region -p raster=gdem_etopo1_ice</div><div>projection: 3 (Latitude-Longitude)</div><div>zone: 0</div><div>datum: wgs84</div><div>ellipsoid: wgs84</div><div>north: 90N</div><div>south: 90S</div><div>west: 180W</div><div>east: 180E</div><div>nsres: 0:01</div><div>ewres: 0:01</div><div>rows: 10800</div><div>cols: 21600</div><div>cells: 233280000</div><div></div></div><div><br></div><div><br></div><div>Equal area projection:</div><div><div>>r.proj location=latlong mapset=base_maps input=gdem_etopo1_ice -g</div><div>Input map <gdem_etopo1_ice@base_maps> in location <latlong>:</div><div>n=6363885.33192604 s=-6363885.33192604 w=-20037508.34278924 e=20037508.34278924 rows=10800 cols=21600</div><div>>GRASS 7.1.svn (eqarea):~ > g.region -p n=6363885.33192604 s=-6363885.33192604 w=-20037508.34278924 e=20037508.34278924 rows=10800 cols=21600</div><div>projection: 99 (Equal Area Cylindrical)</div><div>zone: 0</div><div>datum: wgs84</div><div>ellipsoid: wgs84</div><div>north: 6363885.33192604</div><div>south: -6363885.33192604</div><div>west: -20037508.34278924</div><div>east: 20037508.34278924</div><div>nsres: 1178.49728369</div><div>ewres: 1855.32484655</div><div>rows: 10800</div><div>cols: 21600</div><div>cells: 233280000</div><div>GRASS 7.1.svn (eqarea):~ > r.proj location=latlong mapset=base_maps input=gdem_etopo1_ice </div></div><div><br></div><div>Here are the outputs of r.univar, for both locations:</div><div><br></div><div>Latlong</div><div><div>GRASS 7.1.svn (base_maps):~ > r.univar map=gdem_etopo1_ice -ge percentile=100</div><div>n=58320000</div><div>null_cells=0</div><div>cells=58320000</div><div>min=-10753</div><div>max=8333</div><div>range=19086</div><div>mean=-1892.08140334362</div><div>mean_of_abs=2644.85220128601</div><div>stddev=2650.12442373911</div><div>variance=7023159.46129855</div><div>coeff_var=-140.063974998956</div><div>sum=-110346187443</div><div>first_quartile=-4286</div><div>median=-2456</div><div>third_quartile=214</div><div>percentile_100=8333</div></div><div><br></div><div><br></div><div>Equal-area</div><div><div>GRASS 7.1.svn (eqarea):~ > r.univar map=gdem_etopo1_ice -ge percentile=100</div><div>n=233280000</div><div>null_cells=0</div><div>cells=233280000</div><div>min=-10803</div><div>max=8333</div><div>range=19136</div><div>mean=-2382.28934158093</div><div>mean_of_abs=2845.10169015775</div><div>stddev=2508.93105538271</div><div>variance=6294735.0406638</div><div>coeff_var=-105.315966939504</div><div>sum=-555740457604</div><div>first_quartile=-4544</div><div>median=-3285</div><div>third_quartile=93</div><div>percentile_100=8333</div></div><div><br></div><div><br></div><div>I also tested in python, flattening the raster to an array. The results are the same as r.univar (in both cases).</div><div><br></div><div>best</div><div><br></div><div>Carlos</div><div><br></div><div><br></div><div><br></div><div><br></div><div class="gmail_extra"><br><div class="gmail_quote">On Mon, Nov 16, 2015 at 5:32 PM, Markus Neteler <span dir="ltr"><<a href="mailto:neteler@osgeo.org" target="_blank">neteler@osgeo.org</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">On Mon, Nov 16, 2015 at 5:34 PM, Carlos Grohmann<br>
<<a href="mailto:carlos.grohmann@gmail.com" target="_blank">carlos.grohmann@gmail.com</a>> wrote:<br>
> Hi all.<br>
><br>
> I'm analyzing some global-scale DEMs, like ETOPO1/2, SRTM30_PLUS, etc.<br>
><br>
> I'm getting the statistics for the whole dataset with r.univar, but today I<br>
> noticed that the results differ if I use different projections. (GRASS 7.1)<br>
<br>
<br>
Please post also *how* you reprojected (resampling method etc)<br>
<span><font color="#888888"><br>
Markus<br>
</font></span></blockquote></div><br><br clear="all"><div><br></div>-- <br><div><div dir="ltr">Prof. Carlos Henrique Grohmann<br>Institute of Energy and Environment - Univ. of São Paulo, Brazil<div>- Digital Terrain Analysis | GIS | Remote Sensing - </div><div><br></div><div><a href="http://carlosgrohmann.com/" target="_blank">http://carlosgrohmann.com</a></div><div><a href="http://orcid.org/0000-0001-5073-5572" style="font-size:13px;color:rgb(17,85,204);font-family:arial,sans-serif;background-color:rgb(255,255,255)" target="_blank">http://orcid.org/0000-0001-5073-5572</a><br><div>________________<br>Can’t stop the signal.</div></div></div></div>
</div></div>