Hey- A contributor (mwa at sourcepole.ch?) posted a patch for approximating geodesic areas for polygons [1].
I have used this algorithm to give geometries a getGeodesicArea method. In a similar way, I added a getGeodesicLength method using the Vincenty algorithm already in Util. Combined, these give us handy methods for calculating metrics from our geometries as if they were projected onto the earth's surface. Both of these calculations require that a projection is provided (Geographic/WGS84 is assumed if none is given). This functionality allows a "geodesic" property to be added to the measure control. So, if your map projection is properly set, and if you have provided the appropriate definition for that projection so a transform to Geographic/WGS84 can be done, you can use the measure control to do geodesic measures. All this is wrapped up in a new patch for ticket 1819 [2]. If anybody cares to comment or test it out, that would be appreciated. Tim [1] http://trac.openlayers.org/attachment/ticket/1819/area_measurement.patch [2] http://trac.openlayers.org/ticket/1819 -- Tim Schaub OpenGeo - http://opengeo.org Expert service straight from the developers. _______________________________________________ Dev mailing list Dev@openlayers.org http://openlayers.org/mailman/listinfo/dev
