<div dir="ltr"><div dir="ltr"></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Sat, 13 Apr 2024 at 17:35, Stephen Woodbridge via gdal-dev <<a href="mailto:gdal-dev@lists.osgeo.org">gdal-dev@lists.osgeo.org</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><u></u>
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<div>Thanks, this is NOT the standard Web
Mercator projection. I am aware of EPSG:90013 and EPSG:3857. This
projection is used with HYCOM data that I have extracted into
geotif files so that I can accurately project that onto EPSG:3857.
It took some fiddling with the values to get to overlay visually
correctly. HYCOM data is weird in that it uses two different
projections based on if the data is above or below some latitude.<br></div></div></blockquote><div>I found something like that in the Internet. But I was not sure it was the right one <a href="https://polar.ncep.noaa.gov/global/about/">https://polar.ncep.noaa.gov/global/about/</a> It didn't specify the projections, just a short description as Arctic bi-polar patch north of 47N, and Mercator south of it.<br></div><div><br></div><div>I do not know if you can specify a projection "in parts" respect to parallel 47. Maybe in WKT2.<br></div><div><br></div><div>Where did you found those parameters for the datum and projection? They are quite strange.</div><div><br></div><div>For the ellipsoid there are a few already with a similar radius:</div><div><br></div><div>SELECT * from ellipsoid where semi_major_axis BETWEEN 6371000 and 6371010</div><div><br></div><div><span></span><table border="1" cellspacing="0" cellpadding="2"><tbody><tr><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:normal;font-weight:normal;background-color:rgb(255,255,255);color:rgb(0,0,0);text-align:left">EPSG</td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:normal;font-weight:normal;background-color:rgb(255,255,255);color:rgb(0,0,0);text-align:left">7035</td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:normal;font-weight:normal;background-color:rgb(255,255,255);color:rgb(0,0,0);text-align:left">Sphere</td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:italic;font-weight:normal;background-color:rgb(255,255,255);color:rgb(192,192,192);text-align:left"><br></td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:normal;font-weight:normal;background-color:rgb(255,255,255);color:rgb(0,0,0);text-align:left">PROJ</td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:normal;font-weight:normal;background-color:rgb(255,255,255);color:rgb(0,0,0);text-align:left">EARTH</td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:normal;font-weight:normal;background-color:rgb(255,255,255);color:rgb(0,0,0);text-align:right">6371000.0</td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:normal;font-weight:normal;background-color:rgb(255,255,255);color:rgb(0,0,0);text-align:left">EPSG</td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:normal;font-weight:normal;background-color:rgb(255,255,255);color:rgb(0,0,0);text-align:left">9001</td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:italic;font-weight:normal;background-color:rgb(255,255,255);color:rgb(192,192,192);text-align:right"><br></td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:normal;font-weight:normal;background-color:rgb(255,255,255);color:rgb(0,0,0);text-align:right">6371000.0</td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:normal;font-weight:normal;background-color:rgb(255,255,255);color:rgb(0,0,0);text-align:right">1</td></tr><tr><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:normal;font-weight:normal;background-color:rgb(255,255,255);color:rgb(0,0,0);text-align:left">EPSG</td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:normal;font-weight:normal;background-color:rgb(255,255,255);color:rgb(0,0,0);text-align:left">7048</td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:normal;font-weight:normal;background-color:rgb(255,255,255);color:rgb(0,0,0);text-align:left">GRS 1980 Authalic Sphere</td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:italic;font-weight:normal;background-color:rgb(255,255,255);color:rgb(192,192,192);text-align:left"><br></td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:normal;font-weight:normal;background-color:rgb(255,255,255);color:rgb(0,0,0);text-align:left">PROJ</td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:normal;font-weight:normal;background-color:rgb(255,255,255);color:rgb(0,0,0);text-align:left">EARTH</td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:normal;font-weight:normal;background-color:rgb(255,255,255);color:rgb(0,0,0);text-align:right">6371007.0</td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:normal;font-weight:normal;background-color:rgb(255,255,255);color:rgb(0,0,0);text-align:left">EPSG</td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:normal;font-weight:normal;background-color:rgb(255,255,255);color:rgb(0,0,0);text-align:left">9001</td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:italic;font-weight:normal;background-color:rgb(255,255,255);color:rgb(192,192,192);text-align:right"><br></td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:normal;font-weight:normal;background-color:rgb(255,255,255);color:rgb(0,0,0);text-align:right">6371007.0</td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:normal;font-weight:normal;background-color:rgb(255,255,255);color:rgb(0,0,0);text-align:right">0</td></tr><tr><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:normal;font-weight:normal;background-color:rgb(255,255,255);color:rgb(0,0,0);text-align:left">ESRI</td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:normal;font-weight:normal;background-color:rgb(255,255,255);color:rgb(0,0,0);text-align:left">107047</td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:normal;font-weight:normal;background-color:rgb(255,255,255);color:rgb(0,0,0);text-align:left">Sphere_GRS_1980_Mean_Radius</td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:normal;font-weight:normal;background-color:rgb(255,255,255);color:rgb(0,0,0);text-align:left">Sphere with mean radius based on GRS80</td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:normal;font-weight:normal;background-color:rgb(255,255,255);color:rgb(0,0,0);text-align:left">PROJ</td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:normal;font-weight:normal;background-color:rgb(255,255,255);color:rgb(0,0,0);text-align:left">EARTH</td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:normal;font-weight:normal;background-color:rgb(255,255,255);color:rgb(0,0,0);text-align:right">6371008.7714</td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:normal;font-weight:normal;background-color:rgb(255,255,255);color:rgb(0,0,0);text-align:left">EPSG</td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:normal;font-weight:normal;background-color:rgb(255,255,255);color:rgb(0,0,0);text-align:left">9001</td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:normal;font-weight:normal;background-color:rgb(255,255,255);color:rgb(0,0,0);text-align:right">0.0</td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:italic;font-weight:normal;background-color:rgb(255,255,255);color:rgb(192,192,192);text-align:right"><br></td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:normal;font-weight:normal;background-color:rgb(255,255,255);color:rgb(0,0,0);text-align:right">0</td></tr></tbody></table></div><br><div>And datums</div><div><br></div><div>SELECT * from geodetic_datum where ellipsoid_code in (7035, 7048, 107047)</div><div><br></div><div><span></span><table border="1" cellspacing="0" cellpadding="2"><tbody><tr><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:normal;font-weight:normal;background-color:rgb(255,255,255);color:rgb(0,0,0);text-align:left">EPSG</td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:normal;font-weight:normal;background-color:rgb(255,255,255);color:rgb(0,0,0);text-align:right">6035</td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:normal;font-weight:normal;background-color:rgb(255,255,255);color:rgb(0,0,0);text-align:left">Not specified (based on Authalic Sphere)</td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:italic;font-weight:normal;background-color:rgb(255,255,255);color:rgb(192,192,192);text-align:left"><br></td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:normal;font-weight:normal;background-color:rgb(255,255,255);color:rgb(0,0,0);text-align:left">EPSG</td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:normal;font-weight:normal;background-color:rgb(255,255,255);color:rgb(0,0,0);text-align:right">7035</td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:normal;font-weight:normal;background-color:rgb(255,255,255);color:rgb(0,0,0);text-align:left">EPSG</td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:normal;font-weight:normal;background-color:rgb(255,255,255);color:rgb(0,0,0);text-align:right">8901</td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:italic;font-weight:normal;background-color:rgb(255,255,255);color:rgb(192,192,192);text-align:left"><br></td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:italic;font-weight:normal;background-color:rgb(255,255,255);color:rgb(192,192,192);text-align:left"><br></td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:italic;font-weight:normal;background-color:rgb(255,255,255);color:rgb(192,192,192);text-align:left"><br></td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:italic;font-weight:normal;background-color:rgb(255,255,255);color:rgb(192,192,192);text-align:left"><br></td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:italic;font-weight:normal;background-color:rgb(255,255,255);color:rgb(192,192,192);text-align:left"><br></td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:normal;font-weight:normal;background-color:rgb(255,255,255);color:rgb(0,0,0);text-align:right">1</td></tr><tr><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:normal;font-weight:normal;background-color:rgb(255,255,255);color:rgb(0,0,0);text-align:left">EPSG</td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:normal;font-weight:normal;background-color:rgb(255,255,255);color:rgb(0,0,0);text-align:right">6047</td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:normal;font-weight:normal;background-color:rgb(255,255,255);color:rgb(0,0,0);text-align:left">Not specified (based on GRS 1980 Authalic Sphere)</td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:italic;font-weight:normal;background-color:rgb(255,255,255);color:rgb(192,192,192);text-align:left"><br></td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:normal;font-weight:normal;background-color:rgb(255,255,255);color:rgb(0,0,0);text-align:left">EPSG</td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:normal;font-weight:normal;background-color:rgb(255,255,255);color:rgb(0,0,0);text-align:right">7048</td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:normal;font-weight:normal;background-color:rgb(255,255,255);color:rgb(0,0,0);text-align:left">EPSG</td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:normal;font-weight:normal;background-color:rgb(255,255,255);color:rgb(0,0,0);text-align:right">8901</td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:italic;font-weight:normal;background-color:rgb(255,255,255);color:rgb(192,192,192);text-align:left"><br></td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:italic;font-weight:normal;background-color:rgb(255,255,255);color:rgb(192,192,192);text-align:left"><br></td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:italic;font-weight:normal;background-color:rgb(255,255,255);color:rgb(192,192,192);text-align:left"><br></td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:italic;font-weight:normal;background-color:rgb(255,255,255);color:rgb(192,192,192);text-align:left"><br></td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:italic;font-weight:normal;background-color:rgb(255,255,255);color:rgb(192,192,192);text-align:left"><br></td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:normal;font-weight:normal;background-color:rgb(255,255,255);color:rgb(0,0,0);text-align:right">1</td></tr><tr><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:normal;font-weight:normal;background-color:rgb(255,255,255);color:rgb(0,0,0);text-align:left">ESRI</td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:normal;font-weight:normal;background-color:rgb(255,255,255);color:rgb(0,0,0);text-align:right">106047</td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:normal;font-weight:normal;background-color:rgb(255,255,255);color:rgb(0,0,0);text-align:left">D_Sphere_GRS_1980_Mean_Radius</td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:normal;font-weight:normal;background-color:rgb(255,255,255);color:rgb(0,0,0);text-align:left">GRS 1980 Mean Radius Sphere</td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:normal;font-weight:normal;background-color:rgb(255,255,255);color:rgb(0,0,0);text-align:left">ESRI</td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:normal;font-weight:normal;background-color:rgb(255,255,255);color:rgb(0,0,0);text-align:right">107047</td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:normal;font-weight:normal;background-color:rgb(255,255,255);color:rgb(0,0,0);text-align:left">EPSG</td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:normal;font-weight:normal;background-color:rgb(255,255,255);color:rgb(0,0,0);text-align:right">8901</td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:italic;font-weight:normal;background-color:rgb(255,255,255);color:rgb(192,192,192);text-align:left"><br></td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:italic;font-weight:normal;background-color:rgb(255,255,255);color:rgb(192,192,192);text-align:left"><br></td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:italic;font-weight:normal;background-color:rgb(255,255,255);color:rgb(192,192,192);text-align:left"><br></td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:italic;font-weight:normal;background-color:rgb(255,255,255);color:rgb(192,192,192);text-align:left"><br></td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:italic;font-weight:normal;background-color:rgb(255,255,255);color:rgb(192,192,192);text-align:left"><br></td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:normal;font-weight:normal;background-color:rgb(255,255,255);color:rgb(0,0,0);text-align:right">0</td></tr></tbody></table></div></div><div class="gmail_quote"><br></div><div class="gmail_quote">and geographic crs</div><div class="gmail_quote"><br></div><div class="gmail_quote">SELECT * from geodetic_crs where datum_code in (6035, 6047, 106047)</div><div class="gmail_quote"><br></div><div class="gmail_quote"><span></span><table border="1" cellspacing="0" cellpadding="2"><tbody><tr><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:normal;font-weight:normal;background-color:rgb(255,255,255);color:rgb(0,0,0);text-align:left">EPSG</td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:normal;font-weight:normal;background-color:rgb(255,255,255);color:rgb(0,0,0);text-align:right">4035</td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:normal;font-weight:normal;background-color:rgb(255,255,255);color:rgb(0,0,0);text-align:left">Unknown datum based upon the Authalic Sphere</td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:italic;font-weight:normal;background-color:rgb(255,255,255);color:rgb(192,192,192);text-align:left"><br></td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:normal;font-weight:normal;background-color:rgb(255,255,255);color:rgb(0,0,0);text-align:left">geographic 2D</td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:normal;font-weight:normal;background-color:rgb(255,255,255);color:rgb(0,0,0);text-align:left">EPSG</td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:normal;font-weight:normal;background-color:rgb(255,255,255);color:rgb(0,0,0);text-align:right">6402</td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:normal;font-weight:normal;background-color:rgb(255,255,255);color:rgb(0,0,0);text-align:left">EPSG</td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:normal;font-weight:normal;background-color:rgb(255,255,255);color:rgb(0,0,0);text-align:right">6035</td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:italic;font-weight:normal;background-color:rgb(255,255,255);color:rgb(192,192,192);text-align:left"><br></td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:normal;font-weight:normal;background-color:rgb(255,255,255);color:rgb(0,0,0);text-align:right">1</td></tr><tr><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:normal;font-weight:normal;background-color:rgb(255,255,255);color:rgb(0,0,0);text-align:left">EPSG</td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:normal;font-weight:normal;background-color:rgb(255,255,255);color:rgb(0,0,0);text-align:right">4047</td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:normal;font-weight:normal;background-color:rgb(255,255,255);color:rgb(0,0,0);text-align:left">Unspecified datum based upon the GRS 1980 Authalic Sphere</td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:italic;font-weight:normal;background-color:rgb(255,255,255);color:rgb(192,192,192);text-align:left"><br></td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:normal;font-weight:normal;background-color:rgb(255,255,255);color:rgb(0,0,0);text-align:left">geographic 2D</td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:normal;font-weight:normal;background-color:rgb(255,255,255);color:rgb(0,0,0);text-align:left">EPSG</td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:normal;font-weight:normal;background-color:rgb(255,255,255);color:rgb(0,0,0);text-align:right">6422</td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:normal;font-weight:normal;background-color:rgb(255,255,255);color:rgb(0,0,0);text-align:left">EPSG</td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:normal;font-weight:normal;background-color:rgb(255,255,255);color:rgb(0,0,0);text-align:right">6047</td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:italic;font-weight:normal;background-color:rgb(255,255,255);color:rgb(192,192,192);text-align:left"><br></td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:normal;font-weight:normal;background-color:rgb(255,255,255);color:rgb(0,0,0);text-align:right">1</td></tr><tr><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:normal;font-weight:normal;background-color:rgb(255,255,255);color:rgb(0,0,0);text-align:left">ESRI</td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:normal;font-weight:normal;background-color:rgb(255,255,255);color:rgb(0,0,0);text-align:right">104047</td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:normal;font-weight:normal;background-color:rgb(255,255,255);color:rgb(0,0,0);text-align:left">GCS_Sphere_GRS_1980_Mean_Radius</td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:italic;font-weight:normal;background-color:rgb(255,255,255);color:rgb(192,192,192);text-align:left"><br></td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:normal;font-weight:normal;background-color:rgb(255,255,255);color:rgb(0,0,0);text-align:left">geographic 2D</td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:normal;font-weight:normal;background-color:rgb(255,255,255);color:rgb(0,0,0);text-align:left">EPSG</td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:normal;font-weight:normal;background-color:rgb(255,255,255);color:rgb(0,0,0);text-align:right">6422</td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:normal;font-weight:normal;background-color:rgb(255,255,255);color:rgb(0,0,0);text-align:left">ESRI</td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:normal;font-weight:normal;background-color:rgb(255,255,255);color:rgb(0,0,0);text-align:right">106047</td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:italic;font-weight:normal;background-color:rgb(255,255,255);color:rgb(192,192,192);text-align:left"><br></td><td style="font-family:"DejaVu Sans";font-size:10pt;font-style:normal;font-weight:normal;background-color:rgb(255,255,255);color:rgb(0,0,0);text-align:right">0</td></tr></tbody></table></div><div class="gmail_quote"> </div><div class="gmail_quote">See that EPSG ones are deprecated. (surprisingly the ellipsoid EPSG:7048 is not deprecated, but the datum that uses it is deprecated).<br></div><div class="gmail_quote"><br></div><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div><div>
On 4/13/2024 4:19 AM, Javier Jimenez Shaw via gdal-dev wrote:<br>
</div>
<blockquote type="cite">
<div dir="ltr">
<div>If what you need is really EPSG:3857, yes, use it.</div>
<div><br>
</div>
<div>However I have seen strange parameters on your projection.
The radius of the sphere is the "average" 3671 km, and you set
a false easting and northing of just 4.4 km. Is that trying to
correct the radius of the sphere? I do not know why you need
that.</div>
<div><br>
</div>
<div>Bas, are they really equivalent?<br>
</div>
<div><br>
</div>
<div>In proj you can convert to WKT1 (see that I added
+type=crs):</div>
<div><br>
</div>
<div><span style="font-family:monospace">projinfo "+proj=merc
+a=6371001 +b=6371001 +lat_ts=0.0 +lon_0=0.0 +x_0=-4448
+y_0=-4448 +k=1.0 +units=m +over +nadgrids=@null +no_defs
+type=crs" -o wkt1_gdal</span></div>
<div><br>
</div>
</div>
</blockquote>
Ok I get this adding by <span style="font-family:monospace">+type=crs
but how do I add it to the proj database so I can access it
referencing it by something like EPSG:90014?<br>
<br></span></div></blockquote><div><br></div><div><div>Is a WKT string enough?</div><div><br></div><div>PROJCS["unknown",<br> GEOGCS["unknown",<br> DATUM["unknown using nadgrids=@null",<br> SPHEROID["unknown",6371001,0]],<br> PRIMEM["Greenwich",0,<br> AUTHORITY["EPSG","8901"]],<br> UNIT["degree",0.0174532925199433,<br> AUTHORITY["EPSG","9122"]]],<br> PROJECTION["Mercator_1SP"],<br> PARAMETER["central_meridian",0],<br> PARAMETER["scale_factor",1],<br> PARAMETER["false_easting",-4448],<br> PARAMETER["false_northing",-4448],<br> UNIT["metre",1,<br> AUTHORITY["EPSG","9001"]],<br> AXIS["Easting",EAST],<br> AXIS["Northing",NORTH],<br>
EXTENSION["PROJ4","+proj=merc +a=6371001 +b=6371001 +lat_ts=0.0
+lon_0=0.0 +x_0=-4448 +y_0=-4448 +k=1.0 +units=m +over +nadgrids=@null
+no_defs"]]</div><div><br></div><div>(generated with the projinfo line from prev email) Using a geographic CRS as described above will make it nicer, and probably more compatible.<br></div><div><br></div><div>You
can use it in QGIS for instance. I am not sure how does it behave
in a GeoTIFF, as it has some special tags. You can try to generate the
geotiff with gdal with that WKT, and see that happens.<br></div><div><br></div><div>About adding
to proj.db as EPSG:900914, I am not sure of all the steps. But I would
say that you have to create a datum and a geographic crs (or use one of the above), in addition to
the projection (conversion, parameters, etc) and the projected crs. And then "compile" the database.<br></div><div>Is it worth it?</div><div>In case you modify proj.db, instead of using EPSG, you can create your own authority, or use "PROJ" authority. It will be cleaner.</div><div><br></div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div><span style="font-family:monospace">
Thanks,<br>
-Steve<br>
</span>
<blockquote type="cite"><br>
<div class="gmail_quote">
<div dir="ltr" class="gmail_attr">On Sat, 13 Apr 2024 at 06:17,
Sebastiaan Couwenberg via gdal-dev <<a href="mailto:gdal-dev@lists.osgeo.org" target="_blank">gdal-dev@lists.osgeo.org</a>>
wrote:<br>
</div>
<blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">On
4/12/24 11:24 PM, Stephen Woodbridge via gdal-dev wrote:<br>
> and was able to access it in gdal, mapserver, postgis,
etc with <br>
> "EPSG:900914"<br>
<br>
I used to do that too, but switched to EPSG:3857 its
non-deprecated <br>
equivalent. I would recommend that instead of trying to keep
using a <br>
non-standard projection.<br>
<br>
Kind Regards,<br>
<br>
Bas<br>
<br>
-- <br>
GPG Key ID: 4096R/6750F10AE88D4AF1<br>
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