Blm Marker

[Johnny Vegas]

In the Mohave Natl Preserve (CA), I found a Dept of Interior (BLM) disk with these markings:

T14NR13E (on top)

AP 1 TR 37 (beneath two angled lines)

Cadastral Survey 2004

 

Anyone know what this is? I took a photo of it, but couldn't figure out how to load it into this firum.

 

Thanks

[Neo_Geo]

Someone asked about one of these yesterday...

CLICK HERE

 

I know you from the caching forum - you've been around longer than I have. What's up with the "Tadpole" ranking with 2 posts??? I thought maybe it might be different stats for different forums, but my stats carried over to this one...

 

EDIT: Nope, it's JohnnyVegas (2,571 posts since 1/5/03) that I know from the Geocaching forum - NOT Johnny Vegas

Edited September 8, 2005 by Neo_Geo

[2oldfarts (the rockhounders)]

In the Mohave Natl Preserve (CA), I found a Dept of Interior (BLM) disk with these markings:

T14NR13E (on top)

AP 1 TR 37 (beneath two angled lines)

Cadastral Survey 2004

 

Anyone know what this is? I took a photo of it, but couldn't figure out how to load it into this firum.

 

Thanks

 

We just refer to them as section markers.

 

The top set of numbers are T14N - Township 14 North -- R13E - Range 13 East

 

The next set are AP 1 - Angle Point 1 -- TR37 (? - I don't recall what it is for - someone help me out, Please!).

 

Cadastral Survey 2004 is when the mark was set and measured.

 

John

[+jwahl]

Angle Point 1 Tract 37, it will be an irregular tract in that township. Tracts can be a lot of things, such as a Rancho, Indian Reservation, or something of that nature, in this case possibly even the National Preserve Boundary itself.

 

Seems like we had one like this just a few months ago. I'll have to search my id and see if it shows up.

 

- jerry

 

PS without knowing the area in detail, it seems more likely to be T14N R18E

Edited September 8, 2005 by jwahl

[Johnny Vegas]

Indeed, it is R18E, not R13E... thanks for the info. Are these logable, like benchmarks? As for the name, I recently received an email for JohnnyVegas (no space between). Just a case of a mistaken moniker.

Edited September 8, 2005 by Johnny Vegas

[+Black Dog Trackers]

Johnny Vegas -

 

Cadastral survey marks are only loggable if the mark has been submitted by surveyors to the NGS database (the geocaching database is from the NGS database). It is rather rare for anyone to use an existing cadastral marker in such a manner - there are very few of them in the NGS database; only a tiny percentage of all cadastral markers are in the NGS database.

 

It's generally more productive to look for markers by looking in the database first rather than by finding them somehow and then looking for them in the database.

[holograph]

If the term "cadastral" is unfamiliar to anyone who may be reading:

 

"Cadastral survey" means a property boundary or tax survey. Generally the purpose is to set monuments (or to find and replace old monuments) that provide a durable record of property boundaries. Property boundaries are typically based on distances and directions from other known positions rather than on geographic coordinates, and so the latitudes and longitudes of the monuments were not important. In many portions of the U.S., the virgin land was first surveyed according to a rectangular grid system, and recorded in the form of the township and range Public Land Survey System (PLSS).

 

"Geodetic survey," on the other hand, has as its purpose the establishment of control points relative to standard reference frames (datums), and has no relation to property boundaries. Geodetic survey is important for scientific and engineering purposes, but not so important for property boundaries.

 

The place where cadastral and geodetic surveys met was at the principle meridians and baselines that were the basis of the PLSS system. However, there were often errors in locating those principle meridians. Once a meridian or baseline was established, its precise geographic location was no longer very important, since all remaining property was surveyed with respect to the initial point, errors and all.

 

Only geodetic survey monuments are used for Geocaching benchmark hunting. There are bezillions, or by some estimates, gazillions, of cadastral survey monuments scattered across the land. Very few of these are also geodetic monuments, so most cadastral survey monuments are not loggable.