John Dorado a écrit :
> GeneralEnvelope ge = new GeneralEnvelope(2);
> ge.setRange(0, -150, -120);
> ge.setRange(1, 20, 70);
>
> returns a projected envelope of:
> [-160.817 12.508 , 176.101 72.81]
>
> [...snip...]
>
> GeneralEnvelope ge = new GeneralEnvelope(2);
> ge.setRange(0, -150, -120);
> ge.setRange(1, 30, 70);
> Projected envelope: [-178.617 23.017 , -110.253 72.81]
In the later case, the projected envelope is pretty close to -180° of
longitude: -178.6°. I suspect
that in the former case, the referencing module actually computed -184° of
longitude, and roolled it
to 176°, which is geometrically equivalent. If this is true and assuming that
-184° is an accurate
answer, then Geotools referencing module is not really wrong. The problem is
rather about how to
create a geometric shape crossing the -180° / +180° boundary. A workaround may
be to define a
GeographicCRS with prime meridian over the Pacific Ocean instead of Greenwich,
and define
ProjectedCRS using this shifted GeographicCRS (in Geotools, you should be able
to select whatever
prime meridian you wish).
An other workaround would be to use longitudes in a [0..360°] range instead of
[-180..180°] range.
But this is not yet implemented in Geotools 2.3 - all projection currently
perform their computation
in the [-180..180°] range. However it could be added in some future Geotools
version if there is a
demand for that.
> Is there no way to project a coverage that is close to the
> equator/poles/prime meridian?
Equator should not be a problem for most (but not all) projections. Pole work
for some projections
only. It doesn't work for Mercator, but it can work for some other like
Stereographic. This is
really projection-specific.
However, in the above case, I believe that the problem is rather a -180° /
+180° border crossing
rather than an innacurate projection.
Martin.
-------------------------------------------------------------------------
Using Tomcat but need to do more? Need to support web services, security?
Get stuff done quickly with pre-integrated technology to make your job easier
Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo
http://sel.as-us.falkag.net/sel?cmd=lnk&kid=120709&bid=263057&dat=121642
_______________________________________________
Geotools-gt2-users mailing list
[email protected]
https://lists.sourceforge.net/lists/listinfo/geotools-gt2-users
