SPCS83 for Google Earth (SPCGE)

This page describes a free application that runs in the Google Earth desktop client. Please install Google Earth, download SPCGE, and return to this page to learn more.

SPCGE is a graphical front end for the NGS online tool, SPCS83. It eliminates the need to input geodetic coordinates and displays the converted coordinates, convergence angle, and scale factor in a placemark balloon.

To convert geodetic to plane coordinates:

  1. Position the point of interest (POI) in the center of the view. One way to do this is to double-click an unmarked location. To precisely position the POI in the center of the view, add a placemark at the desired location; then edit the properties of that placemark and reset the view (explain). For best results, disable automatic tilting (Tools, Options, Navigation, Do not automatically tilt while zooming) and minimize elevation exaggeration (Tools, Options, 3D View, Elevation Exaggeration, 0.01).
  2. Check the radio button beside the Geodetic to Plane network link. A form will be presented with read-only coordinates corresponding to the view center and input fields for zone and units. Converted coordinates, convergence angle, and scale factor are displayed when the Convert button is pressed. Output coordinates in feet are converted from the NGS source in meters with three decimal digits.
  3. On subsequent uses, reposition the POI and ensure that the network link is checked and selected. Then choose Refresh from the Edit menu, or right-click and select Refresh in the context menu (explain).

© 2014 Google

To convert plane to geodetic coordinates:
  1. Position the area of interest (AOI) in the viewer.
  2. Check the radio button beside the Plane to Geodetic network link. A form will be presented with input fields for plane coordinates, zone, and units. Converted coordinates, convergence angle, and scale factor are displayed when the Convert button is pressed. Input coordinates in feet are converted to meters with three decimal digits.
  3. On subsequent uses, reposition the AOI and ensure that the network link is checked and selected. Then choose Refresh from the Edit menu, or right-click and select Refresh in the context menu (explain).
Coverage includes the conterminous United States, Alaska, Hawaii, Puerto Rico, and the US Virgin Islands. Check the Extents folder to display the coverage area bounding boxes.

Note: To save SPCGE results from one Google Earth session to another, right-click on Saved Placemarks and select Save to My Places.

All data are retrieved from remote servers. Data errors, accuracy, and availability are beyond the control of this application.