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<DIV>I would like to use Spherical Mercator projection (the earth is a sphere model). </DIV>
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<DIV>My purpose is to produce raster for other software using Mercator projection Sphere formula : merc = ln( tan ( pi / 4 + L / 2 ) ).</DIV>
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<DIV>My test have been using POSTGIS, entering following PROJ.4 parameters :</DIV>
<DIV>+proj=merc +a=6378137 +b=6378137 +lat_ts=0 +lon_0=0 +k=1.0 +x_0=0 +y_0=0 +units=m +nodefs.</DIV>
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<DIV>(a=WGS major axis, b=a (excentricity should be null); I've also tried b=0, +ellips=sphere ... always same result!).</DIV>
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<DIV>Results looks like to be always Mercator ellipsoid projection formula, never SPHERE formula.</DIV>
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<DIV>Is there any way to use PROJ.4 sphere formula ?</DIV>
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<DIV>Thanks. </DIV>
<DIV>Ronan</DIV></DIV><DIV style='{font-family:verdana, arial;font-size: 10px}'>
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