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I am a bit confused on EPSG:4326 and EPSG:900913. I thought that they were both same. Though as I am placing my features over GMaps, which is EPSG:4326, I need to define the srsname of the WFS layer as EPSG:900913 to get it into the right place. If I define srsname as 4326 it is projected somewhere completely wrong.

Could someone explain it a bit more in detail as to what is wrong here?

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    Yes, it does. The two are exactly equivalent. Nov 20, 2012 at 20:25
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    To add to R.K.'s answer, EPSG:900913 uses an authalic sphere.
    – arcsump
    Jan 24, 2013 at 7:55
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    As a point of trivia: 900913 was originally rejected as a credible projection by European Petroleum Survey Group (EPSG) so Google (who invented it for the web) gave it their own number, which if you type it on an old fashioned calculator spells 'googlE' (substitute '9' for 'g' and squint a bit). Eventually EPSG relented and allowed 900913 into its geodetic repository but gave it the number 3857. Jan 24, 2013 at 8:10
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    @arcsump, 900913 (3857) does not use an authalic sphere. It uses a sphere with a radius equal to the semimajor axis of WGS 1984 ellipsoid.
    – mkennedy
    Jan 24, 2013 at 17:52
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    @sylvester-sneekly, Google did not define 900913, Christopher Schmidt of OpenLayers did: crschmidt.net/blog/archives/243/google-projection-900913
    – mkennedy
    Jan 24, 2013 at 17:54

2 Answers 2

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They are not the same. EPSG:4326 refers to WGS 84 whereas EPSG:900913 refers to WGS84 Web Mercator. EPSG:4326 treats the earth as an ellipsoid while EPSG:900913 treats it as a sphere. This affects calculations done based on treating the map as a flat plane which is why your features got plotted on the wrong places.

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    Also, coordinate values will be totally different, EPSG:4326 has decimal degree values (-180 to 180 and -90 to 90) while EPSG:900913 has metric values (-20037508.34 to 20037508.34).
    – Crischan
    Sep 26, 2012 at 8:18
  • Ya i did notice how the co-ordinate values were changing. Thanks
    – Sam007
    Sep 26, 2012 at 16:05
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EPSG:4326 uses a lat/long coordinate system. Latitudes are = 90 to -90 and Longitudes are = 180 to -180

EPSG:900913 uses an x/y axis coordinate system.

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    I think this is the best answer, as it puts the most critical difference front and center.
    – LarsH
    Sep 10, 2014 at 4:54
  • Did you mean EPSG:4326?
    – c0dehunter
    Jul 28, 2016 at 5:11

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