TR: orthographic projection

[Frank Warmerdam]

Stéphane COLZY wrote:
> Hi there,
> 
> Take a look at this :
>  
> See the straight line at the pole ?
>
> Is this a known issue with Orthographic projection?

Stéphane,

This is a known issue.  The current logic to handle polygons and lines
that go over the horizon is described in:

   http://mapserver.gis.umn.edu/development/rfc/ms-rfc-5/

This basically tracks where the features goes over the horizon and
where it comes back, and draws a straight line between them.  I have had
the intention to implement a means to track along the horizon but it is
a bit involved.

In the meantime this is a known problem - not just with orthographic, but
with any projection with an effective horizon - a boundary past which the
projection fails.

Best regards,
-- 
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I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
light and sound - activate the windows | http://pobox.com/~warmerdam
and watch the world go round - Rush    | President OSGeo, http://osgeo.org