Print

Print


Dear Norman,

Calculating the area of an ellipsoid segment is something you probably
don't want to do. Most GIS software does not implement it, those that do
use approximations. You can get an idea of the complexity here:

http://www.math.auckland.ac.nz/Research/Reports/Series/539.pdf

You should do as Mark says, first project that geodetic data using an equal
area projection and then feed it to GeoMason. This way you can use GeoMason
as a GIS.

Best,

Luís


On 13 June 2013 23:14, Norman Langner <[log in to unmask]> wrote:

> Hello,
>
> I'm curious how geomason handles geographic references. I'm importing a
> shapefile with  polygons in the WGS84 reference system. All the points have
> values like 52.03N 7.63E. When I measure the polygon area with a gis then I
> get different values than using the getArea on the polygons geometry.
> Even when I accept that getArea gives me the area in degrees it isn't the
> same m˛ after I convert the value.
>
> I found nothing in the api or the other doc sources where this part is
> described.
> Now I'm not sure what to do. Am I making a mistake or do I miss something?
>
> thanks in advance,
> Norman Langner
>