| Re: [udig-devel] Area of a polygon? |
oh, oh...
by default Udig takes the wgs84 and that is a lat/long. So the problem
could in fact be that one, calculations in degrees...
In the preferences of udig you can set -1 in the Project part in order
to have the Projection set from the map. I would really suggest to set
that as the default instead of the 4236 or whatever, in order to avoid
unseen Problems.
Andrea
tony.roth@xxxxxx probaly wrote:
> I hope I use a metric projection. Where do I have to set the projection
> type? I never set it or change it. In another class I'm using
> JTS.orthodromicDistance(..) to calculate the distance between two points
> and this method returns a value in [m].
>
> tony roth
>
>
>
> Are you using a metric projection?
> I've never had problems with the getArea, but I always use metric
> projection systems.
>
> Ciao
> Andrea
>
>
> tony.roth@xxxxxx probaly wrote:
> > Hi list,
> > how to get the area of a polygon?
> >
> > I draw a polygon roughly covering egypt and both polygon.getArea() and
> > Areafunction.getArea(polygon) return something about 91.4. But
> what? The
> > Wikipedia tells me that egypt has an area of ~1,000,000km² or
> 386,000 sq
> > mi. Ok, my polygon is not perfect but 91,4 is neither km² nor sq mi.
> >
> > Where's my fault?
> >
> > tony roth
> >
> >
> >
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