Survey Mark Hunting
Survey marks or monuments are objects used to mark a precise location and/or elevation on the earth. The markers most survey mark hunters look for most often are 4-inch brass or aluminum disks installed into a stable setting like bedrock, an embedded boulder, a specially-poured concrete monument, a large building or bridge. Earlier survey monuments were made of stone or even buried bottles or jugs.
Some other types of survey marks are also included in the database, such as landmark stations—tall structures that can be sighted on from a distance so that trigonometric calculations can be made. Airway beacons are of this type.
Survey mark hunting, sometimes referred to as “benchmark hunting” regardless of the type of marker being sought, is simply the activity of searching for these survey marks. When we find, or “recover,” a mark, we do not take it or disturb it in any way. We document the mark’s condition and make note of any updates to the description and geographic coordinates that we think are needed. Then, when applicable, we send our report to the National Geodetic Survey (NGS) or the U. S. Geological Survey (USGS).
Getting Started
Beginner’s Guide to Survey Mark Hunting
- Geodetic Glossary (HTML version)
- This is a hypertext version of the 1986 publication by the National Geodetic Survey (also available in .pdf format)
- Joy of Geodetics Part IV: Other Disk Installing Agencies and Representative Disk Examples
- The United States Power Squadrons have provided a series of presentations to instruct members on methods of surveying, types of markers, and procedures for reporting recoveries.
Resources for Survey Mark Hunters
Data
- Survey Mark Data
- Links to official datasheets, data sets, and other sources of survey control
Tools
- NGS PID Search bookmarklet
- GPS Visualizer
- GPS Visualizer: Calculators
- BM finder by radius
- GPX waypoint creator
- NGS PC Software
Inspiration
- Flickr: USGS Geodetic Survey Markers
- Not all are actually USGS markers, or geodetic markers; many different agencies and types are represented.
- Zhanna’s recoveries from 2024
- There are a few nice images here, if I may say so myself.
Zhanna’s Recoveries
Browse by year
- 2024
- 2023
- 2022
- 2021
- 2020
- 2019
- 2018
- 2017
- 2016
- 2015
- 2014
- 2013
- 2012
- 2011
- 2010
- 2009
- 2008
- 2007
- 2006
- 2005
- 2004
- 2003
- 2002
Map of survey mark recoveries
Map of recoveries, 2002 - 2024