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

[Bill Ricker]

aha. Definition of SCALED as it applies to VERTCON bench marks, and how a
civilian GPS can help with those.
(Lots of other good advice too.)

https://www.ngs.noaa.gov/surveys/mark-recovery/mark-descriptions-help.shtml

>
> *Mark Position*
> Many older bench marks were positioned using only scaled map coordinates.
> If you have a more accurate position, please report it. Acceptable
> positions to supersede SCALED come from the following sources:
>
>     ±10 m = "*handheld 2*" consumer-grade GPS with or without WAAS
> correction.
>
>     ±  3 m = "handheld 1" engineer-grade GPS with differential or
> kinematic correction in NAD 83.
>
>     ADJUSTED = A least squares adjustment of geodetic survey project data
>
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