topic Re: webmercator to geographic Conversion equation in ArcGIS API for Flex Questions

webmercator to geographic Conversion equation

tanyabisen — Tue, 06 Dec 2011 09:32:34 GMT

Hi all,

Does anyone know the formula to convert webmercator to geographic coordinates

Thanks,
Tanya Bisen

Re: webmercator to geographic Conversion equation

EstherColero — Tue, 06 Dec 2011 10:23:19 GMT

Hi,

I don't know the formula, but try with com.esri.ags.utils.WebMercatorUtil.

const coordMinWGS84:MapPoint = WebMercatorUtil.webMercatorToGeographic(new MapPoint(map.extent.xmin, map.extent.ymin, map.extent.spatialReference)) as MapPoint;

Regards
Esther

Re: webmercator to geographic Conversion equation

tanyabisen — Thu, 08 Dec 2011 07:37:49 GMT

preferably mathematical formula...please

Re: webmercator to geographic Conversion equation

IvanBespalov — Thu, 08 Dec 2011 08:06:59 GMT

Tanya.
When you're done with FLEX code for equation (pdf ~3MB) (wiki.gis.com), please post your sources. We would be grateful.

Re: webmercator to geographic Conversion equation

FrancescaRiolo — Sun, 27 May 2012 08:31:21 GMT

Would this be the right formulas found at:
http://www.gal-systems.com/2011/07/convert-coordinates-between-web.html
private void ToWebMercator(ref double mercatorX_lon, ref double mercatorY_lat)
{
    if ((Math.Abs(mercatorX_lon) > 180 || Math.Abs(mercatorY_lat) > 90))
        return;

    double num = mercatorX_lon * 0.017453292519943295;
    double x = 6378137.0 * num;
    double a = mercatorY_lat * 0.017453292519943295;

    mercatorX_lon = x;
    mercatorY_lat = 3189068.5 * Math.Log((1.0 + Math.Sin(a)) / (1.0 - Math.Sin(a)));