Abstract

Paper
Local Vertical Datum Conversion, NAVD vs. NGVD
Track: Education
Authors: J. Eldredge

There are three methods that were examined to compare the differences between NGVD '29 and NAVD '88.

First Method

The National Geodetic Survey (NGS) offers the VertCon program to compute the difference between various datums.

Second Method

Measurement is the next method to be reviewed. There are several published NGVD benchmarks of varying quality throughout the town that Eldredge Surveying & Engineering has located with GPS in conjunction with other projects.

Third Method

The third method we reviewed was the comparison of record benchmark information from the Massachusetts Geodetic Survey to the National Geodetic Survey.