I have a very simple kml file written as xml format:

<?xml version="1.0" encoding="utf-8"?>
<kml xmlns:kml="http://earth.google.com/kml/2.2">
  <Document id="featureCollection">
    <Style id="defaultStyle">
          <Data name="innerwater">
          <Data name="shape_len">
          <Data name="shape_are">
          <Data name="perimeter">
          <Data name="sde_sfgis">
          <Data name="objectid">

From the coordinates, you can easily understand that the used datum is WGS-84. But I've been searching the kml documentation for about an hour now and I can't find any tag for datum definition.
Does that mean KML files just support coordinates reported in WGS-84? (I know that google earth coordinates are in WGS-84)
If not, then how a geospatial software will understand what's the datum used? And which formulas should be used to project it on the map?

1 Answer 1


Quoting from here which seems to be a copy of the standard but not in PDF.

KML relies on a single Coordinate Reference System, which is not referenced explicitly in KML files. The encoding of every kml:Location and coordinate tuple uses geodetic longitude, geodetic latitude, and altitude (in that order) as defined in Annex A of the KML specification by the GML Coordinate Reference System (CRS) with identifier LonLat84_5773. The vertical datum, used for altitude measurements is the WGS84 EGM96 Geoid.

  • 3
    Note: in the 2.3 international standard. the CRS information is mainly in annex B which mentions that the 2D portion is based on 4326 (WGS84).
    – mkennedy
    Aug 4, 2016 at 17:38

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