Surveying

This page provides geodetic control information in the City of Lodi.

Vertical Datum

The City has updated to the North American Vertical Datum of 1988 (NAVD 88) and is no longer using the National Geodetic Vertical Datum of 1929 (NGVD 29). Implementation of this update applies to all improvement plans submitted (for first submittal) after January 1, 2017.

The updated benchmark map is provided at City Maps (coming soon) and includes both NAVD 88 and NGVD 29 elevations. Not all of the existing NAVD 29 benchmarks will be updated. The benchmarks that are not updated are “retired” and are no longer shown on the benchmark map. Lists of the NAVD 88 and NGVD 29 benchmarks are linked in the following information. If a new project is based on a “retired” benchmark, the engineer/surveyor will be responsible for adjusting the elevations to a nearby (listed) NAVD 88 benchmark.

Benchmark Maps

Horizontal Datum

All survey work shall be in the California Coordinate System Zone III using the NAD83 (1991) datum. All maps submitted to the City must comply with City of Lodi Ordinance Number 1824 (PDF).

City of Lodi GPS Network Grid

Survey Monument Conservation

Disclaimer

Note: The NGVD 29 benchmark information is provided for reference purposes only. It is the Surveyor and/or the Engineer of Record’s responsibility to ensure that all documents are prepared using the correct datum and that all reference elevations are adjusted appropriately.