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How can I stretch a PNG raster coming from GMT (Generic Mapping Tools 4.5.6) in such a way that does align with google satellite or bing? such raster is in wgs84 and crosses two UTM zones (17 and 18 south). I think this is the problem of the misalignment. I use gdalwarp to convert the PNG to GeoTiff. The raster is served by mapserver 5.6.7 and displayed by openlayers 2.11 as WMS over google or bing. I use epsg:4326 and epsg:3857.

Other WMS in wgs84 (ie. epsg:4326) are served by mapserver, they don't have this misalignment problem with google or bing, but only with the GeoTiff.

I appreciate some support with this please, thanks!!

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1 Answer 1

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I found the solution, "divide and conquer". After I cut the image in small pieces, they aligned correctly with google and my other layers. As I supposed from the beginning, this problem is because this big raster crosses two UTM zones (17 and 18 south), and the normal stretching must occur close to the Equator (its northern edge gets up to 5ºS). Thus, epsg:900913/epsg:3857 exposes clearly this problem or conflict when dealing with epsg:4326. Hope this helps some people dealing with misalignment of rasters (served by whatever they are served) and google (900913).

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