1. NAD 83 Adjustment of NAD 27 of NAD 27

4. North American Datum of 1927 (NAD 27) Clarke 1866 Ellipsoid tied to the Earth at Meades Ranch

5. NAD 83 Ellipsoid Tied to the Earth At its Center of Mass

6. Latitude, Longitude Conversion is on Topographic Maps NAD 27 corner NAD 83 corner

7. Latitude Shifts in Latitude Shifts in Arc Seconds Arc Seconds 1 arc second of latitude is about 100 feet

8. Longitude Shifts in Longitude Shifts in Arc Seconds Arc Seconds 1 arc second of longitude at 34°N is about 85 feet

9. UTM or State Plane NAD27 to NAD83 Grid Conversion is A Three-step Process

10. 1.Convert NAD 27 Convert NAD 27Convert NAD 27 Northings and Eastings Northings and Eastings To Latitude and Longitude To Latitude and Longitude

11. 2. Convert NAD 27 2. Convert NAD 27 Latitude and Longitude Latitude and Longitude To NAD83 To NAD83 Latitude and Longitude Latitude and Longitude

12. 3. Convert NAD 83 3. Convert NAD 83 Latitude and Longitude to Latitude and Longitude to Northings and Eastings Northings and Eastings

13. UTM Northing Shifts across the U.S.

14. UTM Easting Shifts across the U.S.

15. Examples of NAD 27 to NAD 83 Coordinate Conversions 500000.0 m E, 3761961.5 m N (NAD27 UTM 11N) 34.0°, 117.0° (NAD27) 34.000015°, -117.000861° (NAD83) 499920.5 m E, 3762157.6 m N (NAD83 UTM 11N) If I use 34.0°, -117.0°, assume they're NAD83 and project to NAD83 UTM 11N, the results are: 500000.0 m E, 3762156.0 m N

16. The End Result