<html><head></head><body><div style="color:#000; background-color:#fff; font-family:verdana, helvetica, sans-serif;font-size:13px"><div dir="ltr" id="yui_3_16_0_1_1449763382892_30268">Thank you for the reply Mark.<br><br>But I am not sure I understand you.<br>I am trying to pick the right projection in case when a raster spans into two UTM zones. Like in the following image:<br><a class="" rel="nofollow" shape="rect" id="yiv0848720842yui_3_16_0_1_1449763382892_11505" target="_blank" href="https://www.dropbox.com/s/hbn4yqx3ool7j98/raster_two_UTMzones.jpg?dl=0">https://www.dropbox.com/s/hbn4yqx3ool7j98/raster_two_UTMzones.jpg?dl=0</a><span id="yui_3_16_0_1_1449766534511_3229" class=""><span id="yui_3_16_0_1_1449766534511_3234" class="" data-name="Even Rouault" data-address="even.rouault@spatialys.com" data-action="contact-card-menu"></span></span></div><div id="yui_3_16_0_1_1449763382892_30612" dir="ltr"><br></div><div id="yui_3_16_0_1_1449763382892_30611" dir="ltr">Even Rouault helped me in picking the right projection in case of raster spanning through a single UTM zone:</div><blockquote id="yui_3_16_0_1_1449763382892_30960"><div id="yui_3_16_0_1_1449763382892_30639" dir="ltr"><br></div><div id="yui_3_16_0_1_1449763382892_30640" dir="ltr">UTMzone = (floor((longitude + 180)/6) % 60) + 1<br class="" id="yui_3_16_0_1_1449763382892_30627">projection = 32600 + UTMZone, if raster center's longitude > 0</div><div id="yui_3_16_0_1_1449763382892_30678" dir="ltr">projection = 32700 + UTMZone, if raster center's longitude < 0</div></blockquote><span></span><div id="yui_3_16_0_1_1449763382892_30460"><span id="yui_3_16_0_1_1449763382892_30691"><br>However, I am confused which projection to choose when raster spans through two UTM zones. I intend to download rasters which have the following length x width: 50x50 km, 100x100km, 200x200km, 400x400km.<br><br>Djordje<br><br></span></div><br> <div id="yui_3_16_0_1_1449763382892_30271" style="font-family: verdana, helvetica, sans-serif; font-size: 13px;"> <div id="yui_3_16_0_1_1449763382892_30270" style="font-family: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; font-size: 16px;"> <div id="yui_3_16_0_1_1449763382892_30269" dir="ltr"> <font id="yui_3_16_0_1_1449763382892_30272" size="2" face="Arial"> <hr id="yui_3_16_0_1_1449763382892_30598" size="1"> <b><span style="font-weight:bold;">From:</span></b> Mark Johnson <mj10777@googlemail.com><br> <b><span style="font-weight: bold;">To:</span></b> gdal-dev@lists.osgeo.org <br> <b><span style="font-weight: bold;">Sent:</span></b> Thursday, December 10, 2015 3:49 AM<br> <b><span style="font-weight: bold;">Subject:</span></b> [gdal-dev] how to pick the correct projection<br> </font> </div> <div id="yui_3_16_0_1_1449763382892_30277" class="y_msg_container"><br><div id="yiv3595156707"><div id="yui_3_16_0_1_1449763382892_30276" dir="ltr"><div id="yui_3_16_0_1_1449763382892_30574">It seem that EPSG has reserved the numbers</div><div id="yui_3_16_0_1_1449763382892_30610">- 32600-32799 for basic WGS 84 / UTM zones</div><div id="yui_3_16_0_1_1449763382892_30278"><br></div>For these basic WGS 84 / UTM zone *<div id="yui_3_16_0_1_1449763382892_30575">- Northern Hemisphere: add 32600 to the Zone Number</div><div id="yui_3_16_0_1_1449763382892_30280">- Southern Hemisphere: add 32700 to the Zone Number<br></div><div id="yui_3_16_0_1_1449763382892_30343"><br></div><div id="yui_3_16_0_1_1449763382892_30840">On a Spatialite Database, the following Query will list the basic UTM-Zones</div><div id="yui_3_16_0_1_1449763382892_30344"><br></div><div id="yui_3_16_0_1_1449763382892_30283"><div id="yui_3_16_0_1_1449763382892_30331">SELECT</div><div id="yui_3_16_0_1_1449763382892_30329"> srid, </div><div id="yui_3_16_0_1_1449763382892_30328"> auth_name, </div><div id="yui_3_16_0_1_1449763382892_30327"> auth_srid, </div><div id="yui_3_16_0_1_1449763382892_30284"> ref_sys_name, </div><div id="yui_3_16_0_1_1449763382892_30282"> proj4text, </div><div id="yui_3_16_0_1_1449763382892_30286"> srtext</div><div id="yui_3_16_0_1_1449763382892_30844">FROM </div><div id="yui_3_16_0_1_1449763382892_30346"> spatial_ref_sys</div><div id="yui_3_16_0_1_1449763382892_30843">WHERE</div><div id="yui_3_16_0_1_1449763382892_30287">( -- Northern Hemisphere</div><div id="yui_3_16_0_1_1449763382892_30289"> (proj4text = '+proj=utm +zone='||(srid-32600)||' +datum=WGS84 +units=m +no_defs') OR</div><div id="yui_3_16_0_1_1449763382892_30290"> -- Southern Hemisphere</div><div id="yui_3_16_0_1_1449763382892_30291"> (proj4text = '+proj=utm +zone='||(srid-32700)||' +south +datum=WGS84 +units=m +no_defs')</div><div>)</div><div id="yui_3_16_0_1_1449763382892_30324">ORDER BY proj4text;</div></div><div id="yui_3_16_0_1_1449763382892_30325">-- 120 results<br></div><div id="yui_3_16_0_1_1449763382892_30349"><br></div><div id="yui_3_16_0_1_1449763382892_30849">---</div><div id="yui_3_16_0_1_1449763382892_30294">There are other Projections that also use UTM (non-basic)</div><div id="yui_3_16_0_1_1449763382892_30295">- to list these:</div><div id="yui_3_16_0_1_1449763382892_30296"><br></div><div id="yui_3_16_0_1_1449763382892_30299"><div id="yui_3_16_0_1_1449763382892_30350">SELECT</div><div id="yui_3_16_0_1_1449763382892_30323"> srid, </div><div id="yui_3_16_0_1_1449763382892_30322"> auth_name, </div><div id="yui_3_16_0_1_1449763382892_30353"> auth_srid, </div><div id="yui_3_16_0_1_1449763382892_30319"> ref_sys_name, </div><div id="yui_3_16_0_1_1449763382892_30318"> proj4text, </div><div id="yui_3_16_0_1_1449763382892_30858"> srtext</div><div id="yui_3_16_0_1_1449763382892_30298">FROM </div><div id="yui_3_16_0_1_1449763382892_30407"> spatial_ref_sys</div><div id="yui_3_16_0_1_1449763382892_30408">WHERE</div><div id="yui_3_16_0_1_1449763382892_30315">( -- Other Projections that use UTM </div><div id="yui_3_16_0_1_1449763382892_30314"> (srid NOT BETWEEN 32600 AND 32799) AND</div><div id="yui_3_16_0_1_1449763382892_30300"> (</div><div id="yui_3_16_0_1_1449763382892_30302"> (proj4text LIKE '+proj=utm +zone%')</div><div id="yui_3_16_0_1_1449763382892_30303"> )</div><div id="yui_3_16_0_1_1449763382892_30313">)</div><div id="yui_3_16_0_1_1449763382892_30316">ORDER BY proj4text;</div><div id="yui_3_16_0_1_1449763382892_30312">-- 947 results</div></div><div id="yui_3_16_0_1_1449763382892_30369"><br></div><div id="yui_3_16_0_1_1449763382892_30370">Mark Johnson</div><div id="yui_3_16_0_1_1449763382892_30304"><div id="yui_3_16_0_1_1449763382892_30371"><br></div><div id="yui_3_16_0_1_1449763382892_30372">---------------------------------------------------------<br></div></div><div id="yui_3_16_0_1_1449763382892_30305"><div id="yui_3_16_0_1_1449763382892_30404"><br></div><div id="yui_3_16_0_1_1449763382892_30395">Once again, thank you for the help Even.<br class="" id="yiv0848720842yui_3_16_0_1_1449763382892_11432" clear="none"><br class="" id="yiv0848720842yui_3_16_0_1_1449763382892_11434" clear="none"></div><div class="" id="yiv0848720842yui_3_16_0_1_1449763382892_11467">What
happens if the source raster spreads across two UTM zones? Which one
should I pick then? Here is an example (the blue rectangle is the raster
region):</div><div class="" id="yiv0848720842yui_3_16_0_1_1449763382892_11466"><br class="" id="yui_3_16_0_1_1449763382892_30384" clear="none"></div><div class="" dir="ltr" id="yiv0848720842yui_3_16_0_1_1449763382892_11507"><a class="" rel="nofollow" shape="rect" id="yiv0848720842yui_3_16_0_1_1449763382892_11505" target="_blank" href="https://www.dropbox.com/s/hbn4yqx3ool7j98/raster_two_UTMzones.jpg?dl=0">https://www.dropbox.com/s/hbn4yqx3ool7j98/raster_two_UTMzones.jpg?dl=0</a><div class="" id="yiv0848720842yui_3_16_0_1_1449763382892_11505"><br class="" id="yui_3_16_0_1_1449763382892_30389" clear="none"></div></div><br class="" id="yiv0848720842yui_3_16_0_1_1449763382892_11442" clear="none">I intend to download rasters with the following size: 50x50km, 100x100km, 200x200, and 400x400km in length x width.<br class="" id="yiv0848720842yui_3_16_0_1_1449763382892_11444" clear="none"><br class="" id="yiv0848720842yui_3_16_0_1_1449763382892_11446" clear="none">Regards,<br class="" id="yiv0848720842yui_3_16_0_1_1449763382892_11448" clear="none"><div class="" dir="ltr" id="yiv0848720842yui_3_16_0_1_1449763382892_11550"><div id="yui_3_16_0_1_1449763382892_30397" dir="ltr">Djordje Spasic</div></div></div><div id="yui_3_16_0_1_1449763382892_30400"><br></div></div></div><br>_______________________________________________<br>gdal-dev mailing list<br><a ymailto="mailto:gdal-dev@lists.osgeo.org" href="mailto:gdal-dev@lists.osgeo.org">gdal-dev@lists.osgeo.org</a><br><a href="http://lists.osgeo.org/mailman/listinfo/gdal-dev" target="_blank">http://lists.osgeo.org/mailman/listinfo/gdal-dev</a><br><br></div> </div> </div></div></body></html>