EPSG 3857 WGS84 Pseudo Mercator different spheroid size between MapGuide and QGis

[grossigiulia]

Hi, I have the following problem: as you can see with cs wkt, in MapGuide the EPSG 3857 WGS84 Pseudo Mercator use this spheroid SPHEROID [ "WGS84", 6378137,298.25722293]

in QGis, the spheroid is: SPHEROID [ "WGS84", 6378137.000,298.257223563]

The inverse flattening of the spheroid is different and I think the cause is the shortest rounding terrestrial axle.

This means that when I try to use as base Open Street Map (EPSG 3857) in QGis, the overlap with other layers is perfect, conversely in MapGuide there is a shift of some meters.

In MapGuide, using all sources in 3857 (by manually editing the inverse flattening of the spheroid) and manually setting the same CS in Map, the overlap is successful, but our aim is to have the correct overlapping using MapGuide reprojection, so without having to convert all data sources in 3857 and manually intervene every time on wkt.

Is it possible to correct the size of the spheroid in Ellipsoid.CDS files or are there other alternatives to solve this problem?

Thank you

[Norm Olsen]

Pardon the delay. I was unaware of this posting until yesterday.

I have made the request change on my system and the result passed all of the normal tests without failure or any diagnostics. I would like to perform a regression test before submitting this change to the trunk.

Looks like you can make the change to the elipsoid.asc file and recompile the dictionaries if this indeed takes care of your issue.

[Norm Olsen]

Increased the precision of the polar radius specification for the WGS84 ellispoid as suggested. Tested for regressions using the new console test regression test feature. No failures reported. Correction appears in Revision 2753.