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Horizontal and Vertical Control Networks

Vertical Control Network

The City of Santa Rosa's Vertical Control Network is based on the National Geodetic Vertical Datum of 1929 (NGVD 29).  There are over 1300 benchmarks located throughout the city as well as the surrounding area.

This system is tied directly and adjusted to USC&GS  (now the NGS)  Bench Marks in the area.

Data for City of Santa Rosa Bench Marks can be obtained through the City's GIS System. History and background information for the City’s Vertical Control Network is available.

 Horizontal Control Network

The City of Santa Rosa has two Horizontal Control Networks. The original older network is published with values based upon the California Coordinate System Zone 2, NAD 1927, the newer network with NAD 1983 (1991.35 epic) values. Although these systems were established independently some monuments have values in both systems. The NAD 83-91.35 values were established using GPS with adjustments to five High Precision Geodetic Network (HPGN) monuments within and surrounding the City.

Locations and data for City of Santa Rosa coordinate monuments can be obtained through the City’s GIS system. History and background information for these Horizontal Control Networks is available.

Smartphone Access to H & V Control Data

Coordinate Monument and Bench Mark data (as well as the City's GIS System) can now be accessed with a smartphone.

Instructions for Smartphone use

  • Using your Smartphone navigate to the HTML 5 version of the City of Santa Rosa's GIS page.
  • Click on the layer icon (far right of the control bar)
  • Expand "Capital Improvements Engineering"
  • Check the "Survey" layer. You can turn off Address, Sewer and Water layers to help make the map less congested.
  • Go back to the map by pressing the Map icon on the control bar.
  • Zoom in to the area you need information for until you find the Bench Mark (a number preceded by a letter) or Coordinate Monument (numbered) that you need information for.
  • Click on the Orange "I want to" button on the Control Bar and then select "Identify by rectangle."
  • Drag on the map to draw a rectangle over the monuments you need information for.