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

Vertical Datum

The City uses the North American Vertical Datum of 1988 (NAVD 88) and no longer uses the National Geodetic Vertical Datum of 1929 (NGVD 29). All improvement plans submitted (for first submittal) after January 1, 2017 must use NAVD 88.

The benchmark map provided at City Maps includes both NAVD 88 and NGVD 29 elevations. Not all of the existing NAVD 29 benchmarks are updated to NAVD 88. However, no benchmarks are being destroyed. The benchmarks that are not updated will be “retired” and will no longer be shown on the benchmark map. A list of all of the existing benchmarks and their NGVD 29 elevations is linked below. 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.

Horizontal Datum

All survey work shall be in the California Coordinate System Zone III using the NAD83 (2007). All maps submitted to the City must comply with 17.64.020 of the City of Lodi Ordinance No. 1869, pages 280-281 (PDF), and California Public Resources Code Chapter 1 {8801-8819}.

Note: The City GPS Network Grid is NOT to be used as a Basis of Bearing. The City of Lodi Ordinance No. 1869 supersedes Ordinance No. 1824. Basis of Bearing shall be used from common lines referenced in previous surveys and/or deeds of record.

One property corner of the surveyed property shall be tied to a minimum of two (2) found City G.P.S. Control Network Monuments of RS 37-50, SJCR. Maps shall include the following information:

  1.  Zone Description with Epoch,
  2. Names and description of Network Control Monuments,
  3.  Map reference(s),
  4.  Grid factor,
  5.  Rotation of bearings relative to the City of Lodi G.P.S. Control Network, and
  6.  A control diagram detailing ties to surveyed property corner with bearings and grid distances. An example of the survey notes and control diagram are shown below.

Sample Survey Notes

Basis Of Bearings

Sample Control Diagram

Sample Control Diagram

City of Lodi GPS Network Grid

Record of Survey

Survey Monument Conservation

California Land Surveyors Association - Monument Conservation

Benchmark Maps

City Maps - GIS.

Click HERE for instructions on how to retrieve benchmark information and acronyms of the GIS webpage.

Benchmark Archive (NGVD 29) - PDF

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.