Recover Observe Report

Bench Mark Reconnaissance and Recovery

Bench Mark Recovery helps improve and maintain the NSRS, and completing some research and reconnaissance before you go out to recover will save you time. Check out the information below to learn more:

1) Desktop reconnaissance

Bench marks of First and Second order leveling are targeted for GPS observations. Identify where you are looking for survey control. Generally surveyors try to tie into the NSRS without traveling too far from their project areas. Once you have determined your area of interest, use mapping applications to find marks that meet your criteria. The two recommended mapping applications are the NGS Data Explorer and DSWorld. The NGS database does not always get updated when geocachers recover marks on their web site, but DSWorld does provide information from their web site by showing a   when it has been recovered.

To help assist surveyors and geocachers we have also created an ArcGIS Map Package , a zip file for non ArcGIS users and an ArcGIS Online (AGOL) Web Map available using the links below. The Web Map Application is available using any browser and the Map Package and zip file is for users interested in performing their own analysis.

2) Reconnaissance materials

Once you have identified survey control of interest, we recommend you print the Datasheets and any area maps that will assist you in finding and completing reconnaissance at your selected mark(s). If you expect to be in an area with internet connectivity you might skip printing and instead use your phone to look up the datasheets with the NGS Data Explorer. There is also an iPhone App called "Find a Control" that is popular and can be used in the field with cellular coverage.

3) Reconnaissance equipment

Since recovering a mark can be very difficult work here is a list of items that are of use for finding marks. All of these are not needed, but are recommended.

• Logbook or Notebook (computer, tablet or paper with pen or pencil)
• Datasheets (paper or computer)
• Tape measure (100m tape preferred) or EDM laser
• Compass
• Brush hook or Machete
• Flagging (to help relocate the mark for future observation)
• Spray Paint (can paint arrow and "BM" on road towards bench mark)
• Probe (useful for finding benchmarks that might be buried with an inch or two of soil)
• Camera/Phone (for mark recover pictures)
• Survey grade or hand held GPS receiver or GPS enabled phone
• Garden gloves
• Shovel or Trowel
• Paper towel, packaged wiping cloths, rags, napkins, or other such material to clean off disks
• Flat blade screwdriver (for digging and for opening rod covers)
• First aid kit
• Metal detector

4) Bench Mark Hunting

Drive to the marks general location and park to begin your hunt. Begin searching for the mark using the coordinates or the station description from the Datasheet. The station description provides reference objects and their distances to the survey control mark so tape measures or EDM Lasers are very useful. Depending on the topography and vegetation finding bench marks can be very challenging.

5) Photos

Take photos of the mark (close up and eye level), take one horizon photo (preferably facing south) and note any changes to the existing mark description. Photo guidelines are available.

6) Observe and record

Observe and record the coordinates of the mark with a hand held or GPS enabled phone. If any of the station description is no longer valid (i.e. brick wall no longer there) please make note of the changes and look for new reference objects and take new measurements to record and submit. Log the coordinates, any reference object changes and new measurements performed in your log book, tablet, etc double check everything to make sure the coordinates and measurements are correct for submitting a mark recovery. It is also important to note if the current bench mark is GPSable (satellite visibility) with a clear skyline to the south and assure the antennae is clear of metallic objects by one or more meters. Tutorial on GPS visibility. Also make sure the bench mark is in a safe location for extended occupations outside the right of way for rail road tracks, runways, busy highways etc. Safety is of the utmost concern so please do not take care to use precaution when performing observations.

7) Plan for Survey Observation

Once you have recovered the mark and collected the information for a mark recovery you are done with the Recon and Recovery and ready to plan to survey the bench mark. Check out the Collecting Observations web page for information on surveying bench marks.

8) Add your Planned Observation to the ArcGIS Online Map

If you are planning to make observations on bench marks during National Surveyors Week next week please add them to let others know. To add an observation to the map please follow these steps:

1. Perform desktop recon to identify potential bench marks.
2. Perform field recon to find mark and make sure its still there and has satellite visibility. Collect photos and information for mark recovery if possible.
3. Get back to the office and submit recovery and photos.
4. Determine date and time of planned observation.
5. Open the Web Map and zoom to the bench mark (note PID and Designation).
6. On the top left menu there is an "Edit" button.
7. Click on the Green Flag in the left menu.
8. Click on the bench mark you plan to observe.
9. Fill in any information you choose to share.

If you are a Geocacher it is greatly appreciated to submit a Mark Recovery as well as the hand held coordinates if it is a mark with a SCALED position or has not been recovered in over 30 years. You can find more information on how to do this on the Reporting web page.