[Talk-us-massachusetts] Fwd: GPS on Benchmarks Campaign from the National Geodetic Survey

[Bill Ricker]

On Thu, Apr 15, 2021 at 8:58 AM Marc Sevigny <marc.sevigny at gmail.com> wrote:

> Is there a list of benchmarks that we can use to search out markers in our
> area?
>

For the horizontal control markers that they just want to update RECOVERY
information on the datasheet, there's a *NEARLY* complete list/map at
MassDOT (which also has map of Town Corners):

   - https://www.mass.gov/highway-surveys , (bookmark this one also, seems
   more stable)
   - select INTERACTIVE MAP: GEODETIC CONTROL
   <https://gis.massdot.state.ma.us/geodeticcontrol/>
   - Hint: You have to click on the *LAYERS* icon and select a layer; the
   default selection shows NOTHING.
   - If you click on a marker, it pops up a description, and the *MORE INFO*
   link there will open the *NGS DataSheet* with the site description for
   the primary station, 3 reference marks, any auxiliary station, and
the recovery
   history.
   - This gets you to the same information as the
   https://www.ngs.noaa.gov/datasheets/index.shtml index, but via a nice
   Mass map.

The longer since the last recovery, the higher the priority, I guess?

*If* you have the specialized equipment to take survey-grade elevations via
professional GPS, you can filter that MassGIS/MassDOT map for VERTCON aka
true Benchmarks.

I'd already received a tentative report of a damaged/missing disk in one of
the parks, I need to go see what my friend saw and see if it's a Reference
Mark (one of 3) that's missing or the primary station disk itself before we
report it.

Do please note that some of these marker are on private property, including
inside church steeples or on hospital roofs, or within the "no pedestrians"
zones of Interstates/Freeways. I hope i don't need to point out that the
Federal Citizen Science project is not an invitation to tresspass.



-- 
Bill Ricker
bill.n1vux at gmail.com
https://www.linkedin.com/in/n1vux
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.openstreetmap.org/pipermail/talk-us-massachusetts/attachments/20210415/120ede98/attachment.htm>