I tried that first. It was way off. I think by a factor of cos(lat)**2.



On 01/15/2012 03:24 PM, Toby Reinicke wrote:
Do you have the same issue if you just use ring.getArea() function?

On 15 Jan 2012, at 18:31, Jim White<[email protected]>  wrote:

Hi,

I use this to calculate the number of acres enclosed by a linestring:

ring = new OpenLayers.Geometry.LinearRing(geometry.getVertices());
area = ring.getGeodesicArea(new OpenLayers.Projection("EPSG:900913"));
area = Math.floor(Math.abs(area*0.000247105381));

The calculated area consistently produces results that are 2-3% too small. Is 
this an error in my code or is my data the problem?

Thanks,
Jim White
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