California Surveyors Forums

Sounds incredible but its true (and free).

type this HTML link:

http://ngs.tsqmadness.com/ge/index.html

This will show an HTML screen titled "Google Earth - Bench Mark Utilities"
Load Google Earth, Version 4.2 or later if its not loaded already
Go down the screen to "Version:Local v1.5.0" to download file
Save it to hard drive location.
Double click on "doc.kml" to load it into Google Earth

GE will know show control point locations on screen double click to access NGS datasheet. Left task bar will show "Bench Mark Hunter Tool"

Good Luck, Michael Stanton, PLS 5702

You can also get the GCDB in Google Earth. Kind of handy for seeing the section lines and aliquot lines over the aerial. At least they are somewhat accurate.

http://www.earthpoint.us/townships.aspx

Does anyone know how accurate the earthpoint coordinates are? Or where they came from?

I just took a look at earthpoint GCDB overlay on Google Earth for an area West of Fresno. It appears that the section lines per the overlay and those on the ground, often following existing roads, are up to a couple hundred feet apart.

I just looked at a couple of places and get in the area of 100-200' seems to be elevation driven.

I don't know about that. If you're looking in your normal stomping grounds, the area you're looking at is probably several thousand feet higher than the area I was looking at.

The GCDB coordinates are based upon the BLM and GLO surveys, so my guess is that the accuracy is more a function of the vintage of the surveys from which the coordinates were derived. Surveys from the 1860s will likely be +/- a couple hundred feet (maybe more in places), while surveys from the 1980s or 1990s should match up much better.

I looked at two sites one about 3000 feet higher than the other, the location of Higher elev seemed to be about 200+/- and the location of lower elev seemed to be about 75-100'+/- therefore my resaoning of elevation driven, both locations are at fence intersections therefore good site to pick out. Not conclusive but a place to start.

I have found the Lat Longs in So Cal on Google earth to be pretty accurate. Elevs not so good.