I looked up some Mercator formula on Wolfram and I think my equation in
not the correct one. That being said, the data is lat/lon from a third
party program that was imported into PostGIS and then served by GeoServer.
On 01/15/2012 04:42 PM, Tobias Reinicke wrote:
Fair enough. I presume you aren't drawing the linestring by hand yes?
and that there are no obvious rounding errors?
Toby
On 15 January 2012 21:23, Jim White<[email protected]> wrote:
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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