topic Re: Can I convert decimal degrees to Sq Km on client side ? in ArcGIS API for Silverlight Questions

Can I convert decimal degrees to Sq Km on client side ?

praveentadikemalla — Thu, 13 May 2010 13:56:23 GMT

Hi,
Can I convert decimal degrees to Sq Km on client side only or should I create a geoprocessing service to do that?
If I can convert it on client side, please let me how I can do it and what all would be my requirements. I have gone through many sites but didn't find any relevant data. Please help me out

Thanks and Regards
T. Praveen.

Re: Can I convert decimal degrees to Sq Km on client side ?

DominiqueBroux — Thu, 13 May 2010 16:39:13 GMT

The extension method 'ESRI.ArcGIS.Client.Bing.Transform.GeographicToWebMercator(this ESRI.ArcGIS.Client.Geometry.MapPoint)' should be helpful.

/Dominique

Re: Can I convert decimal degrees to Sq Km on client side ?

dotMorten_esri — Fri, 14 May 2010 15:34:24 GMT

The extension method 'ESRI.ArcGIS.Client.Bing.Transform.GeographicToWebMercator(this ESRI.ArcGIS.Client.Geometry.MapPoint)' should be helpful.

You probably don't want to calculate distance and area in WebMercator. The distortions are way too large to be of any use.
Instead I suggest you look at some of the basic formulas for working with spheric coordinates. I usually use this resource for that: http://williams.best.vwh.net/avform.htm

Just as a side note: Decimal degrees is a measure of angle. Square Kilometers is measure of area. Those are two very different things, and doesn't "convert". I'm guessing you mean you have a polygon described by points in decimal degrees, and you would like to know the area of the polygon, right?