[postgis-devel] Re: Q3C

[Paul Ramsey]

We figured this out, remember? We're converting to geocentric
coordinates for the purpose of indexing.

P

On Wed, Mar 18, 2009 at 4:16 PM, Martin Davis <mbdavis at refractions.net> wrote:
> Hmmm.
>
> How will you handle indexing geometries which cross the dateline (which
> includes crossing the poles)?
>
> Paul Ramsey wrote:
>>
>> On Wed, Mar 18, 2009 at 2:41 PM, Paul Ramsey <pramsey at opengeo.org> wrote:
>>
>>>
>>> I'm having a grand time thinking about what the appropriate return
>>> value of geography::geometry is :)
>>>
>>
>> My current thought is an automagical planar projection into an
>> appropriate UTM zone or polar stereographic system, based on the
>> centroid of the feature. With the extra complication of first looking
>> into the projection cache to see what the last projection used was,
>> and if it's close enough, using that. Hopefully that way, in the case
>> of st_function(geog1, geog2) the two arguments would be both cast into
>> the same plane. This would magically allow the geography module to
>> make use of all the geometry functions, and only break for really
>> large objects that exceed our chosen planar areas.
>>
>> P.
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>>
>
> --
> Martin Davis
> Senior Technical Architect
> Refractions Research, Inc.
> (250) 383-3022
>
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