Hi Phil, Don, all,
I've added "orthographic" to the twiki page. So, those on the list so
far for addition are Mercator and Orthographic.
Ethan
Philip Bentley wrote:
> Hi Don,
>
> Vertical Perspective projection made it into CF 1.2, which is why I
> didn't mention it. Yes, I was also assuming that GoogleEarth uses a
> tilted perspective-type projection. But for general whole-globe views,
> the orthographic projection is a useful alternative (and obviously the
> limiting case of vertical perspective - i.e. the perspective point is
> at inifinity).
>
> Regards,
> Phil
>
> On Wed, 2008-05-21 at 07:05 -0400, Don Murray wrote:
>> Phil/Ethan-
>>
>> Philip Bentley wrote:
>>
>> > An obvious one perhaps, but one which we may find increasingly useful /
>> > relevant in light of the rise and rise of GoogleEarth-type
>> applications,
>> > is the Orthographic projection. This being the classic 'view from
>> space'
>> > projection.
>> >
>> > Same grid mapping parameters as the other azimuthal projections, viz.
>> >
>> > grid_mapping_name = "orthographic"
>> >
>> > longitude_of_projection_origin
>> > latitude_of_projection_origin
>> > false_easting
>> > false_northing
>> >
>> > (though off the top of my head I can't think of a scenario where one
>> > would want to use the last two params).
>>
>> I think GE actually uses a tilted perspective view. But,
>> I think CF should support the Vertical Perspective with
>> an ellipsoid. EUMETSAT has GRIB messages with this projection
>> and an elliptical earth.
>>
>> Don
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--
Ethan R. Davis Telephone: (303) 497-8155
Software Engineer Fax: (303) 497-8690
UCAR Unidata Program Center E-mail: edavis at ucar.edu
P.O. Box 3000
Boulder, CO 80307-3000 http://www.unidata.ucar.edu/
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Received on Thu May 22 2008 - 14:58:11 BST
