Coordinates for property Boundarys ?

[YollaBolly]

Is anyone familiar with the LSIS - PLSS (Land Survey Information System)?

http://www.geocommunicator.gov/LSIS6/map.jsp

 

I'm having a hard time trying to determine my property boundarys. I'm able to locate my property Township.Range - Section - 40acre quarters on LSIS and roughly grab the Lat/Lon number from the corners. The one thing that throws me off is that the section boundarys on LSIS do not match the sectoin boundaries on my USGS topo maps. I determined this by plotting the LSIS section coordinates on my USGS TOPO! software. Depening on location they differ by 100ft or more. The LSIS map grid appears to match the old APN (Parcel) map I obtained fom the county building division (the APN map has no coordinates). Note that both the LSIS and USGS TOPO maps do share the same coordinates for landmarks such as streams and roads. So its only the Township / Range boundarys that differ.

 

Why do the county APN maps and LSIS grid maps not match the USGS topo map section boundarys? Is grabbing coordinates from the online LSIS accurate? Anyone have seggustions on how to obtain coords for property boundary?

 

Location is in Northern CA.

Thanks.

[DaveD]

These sources should be used with great caution. None of them reflect the true position of the PLSS corners. The vast majority of PLSS corners do not have an accurate coordinate associated with them and values obtained from sites such as these should be used only as a gross estimate of the corners actual location. The true location must be determined by recovery of original or reestablished monuments on the ground and review of all associated survey documentation to make sure that the recovered monument is the correct monument. This should be left to a licensed land surveyor. Once the original monumentation has been recovered and accurately positioned relative to the National Spatial Reference System, then it may be possible to determine the relative coordinates of your particular parcel - this should also be left to a licensed land surveyor to determine the correct location of your corners.

[CallawayMT]

YollaBolly,

 

As DaveD pointed out, you should not rely on the LSIS for accurately locating your property boundaries, that can only be performed by licensed land surveyor in the state in which you are located. That being said, to answer your question. The LSIS system is based on the GCDB - Geographic Coordinate Data Base for the PLSS states. The GCDB was created by the BLM - Bureau of Land Management for each of the meridians in which the land title is based upon. In Northern California this could be either the Mount Diablo Meridian or the Humboldt Meridian. Whichever meridian is the base for your land title is the initial point for all surveys within that system.

 

So to create the GCDB or LSIS coordinate values, the BLM had people within their agency or contractors who took all of the original surveys within a township and they would abstract(enter the bearings and distances) for each line of the survey and also any subsequent retracement surveys and sometimes private retracement state authority surveys. This information for each survey then creates a cogo(coordinate geometry) data base which is soley based on the record information; once you put a position on one of the corners within the data base then positions are automatically created for the rest of the corners. Not only do the corners which were set, but all of the corners down to 1/16 corners are created based on the rules for PLSS subdivision. So the more corner positions which are entered into a control file the more accurate the computed positions become for the rest of the corners.

 

This control file was generally based on digitized(picked from a USGS quadrangle map) corner position. They would generally use the "+" on the quad maps because there was usually evidence of a corner at that position during the USGS mapping.

 

So what you have are coordinates that may or may not be accurate based on USGS mapping and a person who used some of these corners and sometimes they did not, you can have a very accurate coordinate for a corner or it could be off by hundreds of feet. So if the control is off, then the rest of the corners will be off also. This is one source of error, another source of error is the quality of the surveys that were done by the General Land Office surveyors and the contractors originally. If they did poor work or as what happened in many areas of California, fraudulent surveys were submitted, then you have more sources of error.

 

Use the data bases that are available to you, but always understand there are problems with data bases and there are subsequent surveys which can affect your land. A land surveyor will conduct the title and boundary research to verify and retrace your land boundary, they will point out problems that may or may not exist with your parcel, such as encroachments or Right-of-Way or Easements that can cloud your title. Land Surveying is not an exact science and there can be different interpretations for evidence which is found on the ground; so the cheapest survey is not always your best option. You want to find a surveyor that is thorough in their research and will document and explain their findings and the interprtations that they come up with on your survey. You also want everything properly filed for your benefit and protection.

 

Good Luck,

CallawayMT

[YollaBolly]

Thanks for the replys.. I have BLM land on one side and Timber company on the 2 sides. I contacted BLM to see if they had some coordinates of there boundary but they never followed up. There's also an established road easment through a portion of it. The USGS topo map has a "+" at a section corner but thats about 1 mile away. Is it typical for the "+" and some of the other section corners have monuments on the ground?

[CallawayMT]

Thanks for the replys.. I have BLM land on one side and Timber company on the 2 sides. I contacted BLM to see if they had some coordinates of there boundary but they never followed up. There's also an established road easment through a portion of it. The USGS topo map has a "+" at a section corner but thats about 1 mile away. Is it typical for the "+" and some of the other section corners have monuments on the ground?

 

The "+" indicates something used for the corner at the time of mapping. Originally most of the section and 1/4 corners were monumented if you know what to look for, they should be out there. The BLM would not necessarily have coordinates other than those in the LSIS or GCDB.

 

Good luck

[Wintertime]

Someone recently showed me some corner markers (blazed trees and metal caps) in Yosemite, and I've been chatting in email with someone else who has looked for a lot of them. The latter person directed me to the CGDB for California, which is linked from a page on the BLM's cadastral survey website. I couldn't make hide nor hair of the data, so he ended up sending me a text file containing the section and corner coordinates for Yosemite.

 

Anyway...perhaps "YollaBolly" can figure out the CGDB files better than I could. Note: the coordinates are in UTM, but there are places on the Web where you can convert them if you need DDMMSS or some other representation.

 

Patty

[YollaBolly]

Someone recently showed me some corner markers (blazed trees and metal caps) in Yosemite, and I've been chatting in email with someone else who has looked for a lot of them. The latter person directed me to the CGDB for California, which is linked from a page on the BLM's cadastral survey website. I couldn't make hide nor hair of the data, so he ended up sending me a text file containing the section and corner coordinates for Yosemite.

 

Anyway...perhaps "YollaBolly" can figure out the CGDB files better than I could. Note: the coordinates are in UTM, but there are places on the Web where you can convert them if you need DDMMSS or some other representation.

 

Patty

 

There's a lot of data in there!!!! Not sure if I can make sense of it nor if any of it will define the true corners based on previous input from the others. I will dig into some more. If I can find some of those monument markers then I should be set. Found this description of the markers on that site. http://www.blm.gov/cadastral/Manual/pdffiles/cornsub.pdf

Edited December 4, 2007 by YollaBolly