Andrea Aime a écrit :
> The reason is that Martin said he would have preferred to handle
> this in a different way, like adding a parameter to Mercator1SP
> to forget about the sphere to ellipse correction for lon/lat
> values, so I never moved it to gt2.
>
> Martin, what's your position on this one?
I though that it was already implemented in Geotools and no special class were
needed anymore? There is the idea: usually a ProjectedCRS is declared in WKT as
below (trimmed):
PROJCS["WGS 84 / World Mercator",
GEOGCS["WGS 84", DATUM[...
SPHEROID["WGS 84", 6378137.0, 298.257223563], ...
PROJECTION["Mercator (1SP)", AUTHORITY["EPSG","9804"]],
PARAMETER["latitude_of_origin", 0.0],
...
In normal WKT there is no PARAMETER[...] for "semi-major" and "semi-minor" axis
length because there are inferred from the enclosed SPHEROID element. However
for the special case of Google projection, we just need to add explicit axis
length definition, which override the SPHEROID definition.
It seems to me that I updated GeoTools in order to allow the above behavior. But
we may need a volunter for trying it. No special class needed. Just write down
the WKT and add explicit:
PARAMETER["semi-major", ...],
PARAMETER["semi-minor", ...]
elements with the same axis length (I don't remember what the value is). Parse
that WKT and it should work. If it really works, maybe we should add a line for
900913 in the "unnamed.properties" file in plugin/epsg-extension.
Martin
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