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Coordinates and Maps Module This is a web site that covers the basics of coordinates in the real world with no mathematics. It has a lot of useful information in the text and examples. It covers the latitude,longitude and height on the spherical earth, on the ellipsoidal earth, and the real world. Examples of different types of maps are included.

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Coordinates Notes

Coordinates (525 Kbytes) are the key to using any map or geographic / geospatial data base. This paper describes Cartesian and Angular coordinate systems. It discusses the three main types of latitude. Both Terrestrial and Celestial Frames are covered.

Datums (775 Kbytes)  are very important in map making and map use. This is true for both paper and electronic maps. Many navigation accidents have been caused by datum errors.

What Datum Am I On (12 KBytes) Short discussion of what datum you get in GPS, Surveying, and with Maps.

A glossary of terms about coordinates

Interactive Coordinate Converter
This page converts latitude,longitude, and height to earth centered, earth fixed (ECEF) coordinates. The WGS84 ellipsoid is uses.

Interactive Earth Box Track

Given starting position a box is traced going east, north, south, and west. Different options as to stepping method and earth model are available.

US Datum Transformation from NAD27 to NAD83 (WGS84) using Molodensky Transform. Done with US average distortion values (origin offset) and with precise distortion parameters. Precise value interpolated from contour plots.

Interactive NAD27 -> NAD83

Not for Precision Conversions

1.  Coordinate Conversions
    Latitude,Longitude,Height -- Cartesian
    Geodetic -- Geocentric Latitude

2. Radii of the Earth

The Geographer's Craft, University of Colorado
This is an extremely good and complete tutorial on Geodesy, Maps, GPS and related topics. It is well organized. The different sections are fairly independent. Originally developed at the University of Texas, it is now at the University of Colorado.

NIMA Publications
NIMA Geodesy and Geophysics Publications Page
         with Geodesy for Layman and other NIMA Publications
NIMA Safety Publications Site Contains Bowditch

NPS OC 2902 - Site Map

Last Modified/Reviewed: 10 March 2003 Approved for public release by Point of Contact: James Clynch Disclaimer, Privacy and Security Notice, and External Links Notice

Material contained herein is made available for the purpose of peer review and discussion and does not necessarily reflect the views of the Department of the Navy or the Department of Defense.