Hi Jon,
I just found some time to look at the source of netcdf-java 4.1. As far
as I can see, only some projections (LambertConformalConicEllipse,
AlbersEqualAreaEllipse, UTM) support ellipsoids, while the others use a
constant spherical earth with EARTH_RADIUS = 6371.229km
In particular, Stereographic projection doesn't support ellipsoids, so
this explains the offset in my maps.
Would be nice to have this assured by one of the unidata-developpers. I
mainly checked the ucar/unidata/geoloc/projection sources.
Best regards,
Heiko
On 2010-03-10 14:38, Jonathan Blower wrote:
> Hi Heiko,
>
> This is a good question. ncWMS relies on netcdf-java for converting coords
> to wgs84 lat lon, so I'm copying this to the mailing list in the hope that
> someone can enlighten me about ellipsoid support in the library.
>
> Cheers, Jon
>
> -----Original Message-----
> From: Heiko Klein <Heiko.Klein@xxxxxx>
> Sent: 09 March 2010 08:54
> To: Jonathan Blower <j.d.blower@xxxxxxxxxxxxx>
> Subject: ncWMS and ellipsoid-support in CF-1.2
>
> Hi Jon,
>
> I currently try to visualize some satellite ice-maps over the north-pole
> with ncWMS, but the data seems to be displaced by some 10-30km compared
> with the land-maps (generated by mapserver).
>
> While geo-tools and therefore ncWMS support lots of coordinate reference
> systems for the presented maps, the support for ellipsoids was only
> added to CF-1.2. Do you know if ncWMS already supports the CF-1.2
> features like semi_major_axis/semi_minor_axis for input-files, or does
> it assume the CF-1.0 spherical earth with 6371km radius?
>
> Best regards,
>
> Heiko
>
