Ngs Database And Geocaching Database

[Parsa]

I'm doing research on US Highway 80 and the old auto trails that preceded it. It's very helpful to look at benchmarks since they reference the highways and allow me to distinguish various alignments of the road as they changed over the years.

 

For instance, in San Diego and Imperial counties, there was an old 1927 route that was the Lee Highway or Old Spanish Trail. Then there was the later asphalt US80. The topo maps, which as you know are often kind of old, show a number of benchmarks that do not show up on geocaching.com's database. I have found most in the NGS database, but sometimes there is no description.

 

Why are these benchmarks not listed (even if not found or destroyed)?

 

Here's an example that has an designation number similar to several others nearby:

DC0121 Z 58 32 42 35. /116 03 17. X

[no further description appears in the datasheet.]

 

Benchmark Y 58 from 1927 is not far south, and it does appear in the database on geocaching (and was found!).

 

Parsa

[+Shorelander]

I believe the geocaching database filters out the marks that have been reported as destroyed to the NGS. Looking up the datasheet, that little 'X' at the end of your copied coordinates means the surface mark has been destroyed. I think the idea is that there was no reason to incorporate those into the GC database, as there's nothing there (theoretically) for people to look for.

 

I know that some people have found marks that have been reported destroyed, but at this point those are marks non grata for hobbyists. (Obsessionists, no.)

[Parsa]

I checked the box for destroyed marks and got a full description. The last note was:

 

DC0121 STATION RECOVERY (1977)

DC0121

DC0121'RECOVERY NOTE BY NATIONAL GEODETIC SURVEY 1977

DC0121'DESTROYED THIS DATE, DISK NOT RECOVERED, SHANK AND DISK INDENTATION

DC0121'WAS SEEN.

 

Still, the location of where the disks were is still of help for what I need. Thanks.

 

Parsa

[+Black Dog Trackers]

Parsa -

 

A great many of the "BM" on topo maps never were on the NGS database (therefore not on the geocaching database either).

 

The USGS set those benchmarks as part of the effort of making their topo maps. The NGS and USGS are completely separate government agencies. Some of the USGS marks are included in the NGS database for various reasons (e.g. I don't know what all the reasons are ).

 

See this post and this post.

[Wintertime]

In addition to the other reasons that folks have mentioned, some NGS benchmarks are not in Gc.com's database because the latter is a snapshot of the former taken several years ago.

 

Patty

[+BuckBrooke]

And there's a large number of NGS stamped disks that aren't in their own database, for various reasons.

[Wintertime]

And there's a large number of NGS stamped disks that aren't in their own database, for various reasons.

Yeah, that always surprises me when I find one of theirs that isn't in their database!

 

Patty