Monday, February 6, 2012

Google Mapplet for State Plane Coordinate System readout


The State Plane Coordinate System (SPCS) is a map coordinate system commonly used in the United States. Most SPCS zones are based on the Transverse Mercator, Lambert Conformal Conic or Hotine Oblique Mercator projections. For more information about SPCS, visit this site at http://en.wikipedia.org/wiki/State_Plane_Coordinate_System.
This Google Mapplet can be used to display any State Plane Coordinate System coordinates. You do have to choose which coordinate system to use e.g. Alabama East Zone FIPS101 and the NAD83 datum. Then simply click anywhere on the map and the mapplet will display the SPCS easting, northing coordinates as shown below.
The datum transformation between the WGS84 datum used by Google Maps and the local NAD27 or NAD83 projection datum is done using the Standard Molodensky transformation. Parameters for the datums and ellipsoids are taken from the University of Colorado.

Click this link http://dominoc925-pages.appspot.com/mapplets/cs_spcs.html to run the mapplet.

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