[geotk] Easy way to detect a horizontal 2D CRS?
Martin Desruisseaux
martin.desruisseaux at geomatys.fr
Tue Oct 13 11:53:42 EDT 2009
Jon Blower a écrit :
> Is there an easy way to determine, for example, that a
> CoordinateReferenceSystem object represents a 2D horizontal CRS? I
> would guess that most of the 2D CRSs are currently horizontal, but one
> could imagine an x-z coordinate system that would not be.
In the 2D case, I use the following criterion: The CRS is considered horizontal
if it is either an instance of GeographicCRS, or a CRS derived from
GeographicCRS (this include the ProjectedCRS case). The 3D case is a little bit
more difficult; for now I rely on axis directions, which is not really
future-proof as you point out.
An easy way to make this check is to use the following convenience method:
http://www.geotoolkit.org/apidocs/org/geotoolkit/referencing/CRS.html#getHorizontalCRS%28org.opengis.referencing.crs.CoordinateReferenceSystem%29
So in the 2D case, the following idiom should evaluate to "true" if the CRS is
horizontal:
if (crs == CRS.getHorizontalCRS(crs)) {
// Horizontal case
}
Martin
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