See:

• http://en.wikipedia.org/wiki/Geocodes
• http://en.wikipedia.org/wiki/Geographic_coordinates

The new World Geodetic System was called WGS 84. It is currently the reference system being used by GPS.

• http://en.wikipedia.org/wiki/GPS_coordinates

• Google Earth → howto Importeren van adressen
• http://earth.google.com/userguide/v4/tutorials/import.html

je kunt ook Google Maps gewoon de coordinaten invullen (ipv straat/plaats):

• degrees/minutes/seconds
  → http://maps.google.nl/maps?q=52+11+15.09+N+5+23+23.93+E
• decimal degrees
  → http://maps.google.nl/maps?q=52.187525,5.389981
• Query met naam:
  → http://maps.google.nl/maps?q=Steenbes%4052.187230,5.389030
• CGI style:
  → http://maps.google.nl/maps?ll=52.187303,5.389915

• Google URL Address Shortener → http://goo.gl/

There are three commonly used units types:

• Degrees Minutes Seconds - DD MM SS (Example = 39 54 32 W).
• Decimal Degrees (Example = 39.909deg) - The minutes and seconds (54 32) are converted to decimal format (.909).
• GPS Coordinates (Example = 39deg 54.333min) - The seconds (32) are converted to decimal format (.333).

Online convert tools:

• http://www.fcc.gov/mb/audio/bickel/DDDMMSS-decimal.html
• http://www.cosports.com/tools/gps_coords.htm

• Geo-Server → http://geoserver.org/display/GEOS/Welcome
• Web Forms → http://www.orbeon.com/ops/welcome/

• from: http://lifehacker.com/267361/how-to-find-latitude-and-longitude

javascript:void(prompt('',gApplication.getMap().getCenter()));

• Universal Transverse Mercator (UTM) coordinate system
• convert UTM → http://www.rcn.montana.edu/resources/tools/coordinates.aspx

In Google Maps, you can export your map with the button “View in Google Earth” (NL: “Weergeven in Google Earth”). This will download a KML file. But this KML does NOT contain the GPS coordinates. Instead it contains a web-reference (HREF) to Google Maps.

Example:

<?xml version="1.0" encoding="UTF-8"?>
<kml xmlns="http://earth.google.com/kml/2.2">
<Document>
  <name></name>
  <description><![CDATA[]]></description>
  <NetworkLink>
    <name></name>
    <Link>
      <href>http://maps.google.nl/maps/ms?hl=nl&amp;...
            &amp;msid=103949872864124130000.0001234b8d6c93f97656a&amp;output=kml
      </href>
    </Link>
  </NetworkLink>
</Document>
</kml>

Here is how to get the KML-file with all the GPS coordinates:

• download the KML-file
• open the KML-file in a text-editor.
• extract only the URL (web-address in <href>-tags)
• rename the string &amp; to just &
• copy-paste the URL in a browser and hit enter
• now it will download a new KML-file with the GPS coordinates

This is an example of the resulting KML-file:

<?xml version="1.0" encoding="UTF-8"?>
<kml xmlns="http://earth.google.com/kml/2.2">
<Document>
  <name>d0907 Tour de Vin de France</name>
  <description><![CDATA[]]></description>
  <Placemark>
    <name>Le Brulot</name>
    <description>
      <![CDATA[<div dir="ltr">Antibes<br>Le Brulot 3</div>]]>  
     </description>
    <styleUrl>#style12</styleUrl>
    <Point>
      <coordinates>7.127367,43.581200,0.000000</coordinates>
    </Point>
  </Placemark>
</Document>
</kml>

Short version:

• Just take the Google-Maps URL and add at the end: &output=kml

• http://maps.google.com/help/maps/getmaps/
• http://code.google.com/apis/maps/
• http://paulstamatiou.com/how-to-embedded-google-maps
• http://extensions.joomla.org/extensions/1147/details
• http://mapki.com/wiki/Main_Page

Geocoding is the process of converting addresses (like 
"1600 Amphitheatre Parkway, Mountain View, CA") into geographic 
coordinates (like latitude 37.423021 and longitude -122.083739), 
which you can use to place markers or position the map.

• Geocoding
• via API: http://code.google.com/apis/maps/documentation/services.html#Geocoding
• via Web Services
  → http://code.google.com/apis/maps/documentation/geocoding/index.html

• http://code.google.com/apis/kml/documentation/kml_tut.html
• CPAN Geo::GoogleEarth::Document
• example on Geo::GoogleEarth::Document
• CPAN Geo::KML