In case any Texas surveyor hasn't realized this, the original survey lines shown on the GLO GIS are not very accurate. Don't use them for any purpose other than sort of telling you where a corner *might* be within perhaps 300 or 400 feet (if you're lucky).
I started work on a project today in which the assignment was to figure out which of two somewhat recent surveys had correctly located a land grant line originally run in 1882. The two different surveys showed locations that differed by about 80 ft. horizontally, one being about 80 ft. North of the other.
After preliminary work on the ground, it's obvious that the original corner is in fact more than 80 ft. South of the more northerly position. Enough original evidence from the 1882 survey remains that this isn't a "maybe". So, what went wrong? After examining the Texas GLO GIS, I'm pretty sure that one of the surveyors just lifted the location shown in the GIS and based both the map and metes and bounds description upon that picture. This placed more than half of the tract surveyed in another land grant entirely and fueled an entirely needless lawsuit between the adjoining land owners.
Best practice is to consider the GLO GIS to be less reliable than rural addresses in Google Maps. If you're stuck trying to put original survey lines on the ground from the GIS, you might as well throw in the towel and find another area of endeavor.
Apparently not all of the desperados have run out of Texas. Please tell us this was some wandering Okie. On second thought, we don't need any more information about the perpetrator He should already be suffering enough.
Amen on that. No better than tax maps. Just put on he map by a cad monkey where they look like they might be.
> Amen on that. No better than tax maps. Just put on he map by a cad monkey where they look like they might be.
More than a CAD monkey. Not too long ago all of them would stretch the drawing to fit the map/picture better. I still have issues with that one here. Never cease to amaze me.
Another entity to be careful is the TopoQuads. Some believe they are gospel and I've proven many times they aren't. Some section corners being 500ft from the TopoQuad location. I guess I better move that stone!
Most GIS maps published by Gov't agencies usually have a obvious 'in your face' billboard style disclaimer upon entering the portal.
I would think that the disclaimer would be unassailable by the brightest attorneys.
> Most GIS maps published by Gov't agencies usually have a obvious 'in your face' billboard style disclaimer upon entering the portal.
> I would think that the disclaimer would be unassailable by the brightest attorneys.
There isn't any question but that the GIS does not present itself as a spatially accurate representation of the original land grants. The problem I'm working on is one that was created by a surveyor using the GIS as if it were a very good picture that he or she could lift the geodetic coordinates of corners from to transfer them to a survey map.
Arizona too
I saw that done on a commercial shopping center "survey." The lines matched the GIS exactly, which means they were off 7' east/west and 2' north/south as compared to the original subdivision monuments still in place. But, it was faster this way and saved the cost of a real survey. Difficult to explain to the SBTR, though. They called it fraud for some reason.
I trust this is a future topic of continuing education for this individual, if not already documented.
Case in point.
About six years ago I did an extensive design survey mapping everything along a mile long corridor to a new prison being built. The drafter who I turned the data over to 'forgot' to use it in the final design drawings and instead relied on the 'records' maps which are based on the local government's GIS which in turn is based on protracted values for all the GLO section corners, everything else being rubber sheeted in and best guessed as to location. The engineer in charge, assuming that the drawing was based on the survey then decided he didn't need anything staked for the location of a $100k switch and used the drafter's drawing to pull distances from utility poles to locate the switch. Later I was called in to do an as-built of the finished improvement and as it turned out it was placed dead center in the middle of a unimproved 100' wide ROW to the new prison. It was intended to be placed 5' outside of that ROW.
The engineer did his best to pin this on me and after I'd uncovered what had happened, I had to tell him that if I do a survey and someone does not to use it, that's on them, not me. He sure saved a bundle not having me stake the location for him.
I'd like to say that lifting information from the GLO GIS is unbelievable, but then, one should never underestimate those who are ignorant or stupid, or both.
Some interesting information about the OTLS linework from the metadata:
Abstract: An interpretation of the Original Texas Land Surveys boundaries and bay tracts. The dataset was derived from the Texas General Land Office (GLO) county maps, the GLO Abstract of Original Land Titles:Volumes and Supplements, and the GLO maps of State-Owned Submerged Lands of the Texas Gulf Coast (bay tracts). The GLO county maps, showing the boundaries of the original land grants of the State of Texas, were compiled and drawn by GLO draftsmen. This dataset is a digital interpretation of the geographic placement of the original land grants and bay area tracts depicted on these GLO maps and is not a legal survey product.
PLEASE NOTE: This dataset is NOT intended to be used as an authoritative public record for any geographic location or as a legal document and has no legal force or effect. Users are responsible for checking the accuracy, completeness, currency and/or suitability of this data.
Use_Constraints:
This dataset is continually being updated and refined and is intended solely for the internal use of the Railroad Commission of Texas (the Commission). The Commission shall not be held liable for use of this dataset, which is provided as a public service for informational purposes only. PLEASE NOTE: This dataset is NOT intended to be used as an authoritative public record for any geographic location or as a legal document and has no legal force or effect. Users are responsible for checking the accuracy, completeness, currency and/or suitability of this dataset themselves. The Commission makes no representation, guarantee or warranty as to the accuracy, completeness, currency, or suitability of this dataset, which is provided "AS IS". The Commission specifically disclaims any and all warranties, representations or endorsements, expressed or implied, with regard to this dataset, including, but not limited to, the warranties of merchantability, fitness for a particular purpose, or noninfringement of privately owned rights. The Railroad Commission recommends that any graphic product made from this dataset should include the statement "Interpreted survey lines provided by the Railroad Commission of Texas; this is not a survey product."
Completeness_Report:
Multiple quality and accuracy checks were performed during the preparation and digitization of this dataset. Line placement was visually checked before and after digitization. Attribute data were electronically tested using internal software. The GLO Abstract of Original Land Titles was the primary source for verification and cross-reference of attribute information shown on GLO county maps.
Lineage:
Source_Information:
Source_Citation:
Citation_Information:
Originator: General Land Office county maps
Title: Original Texas Land Survey
Source_Time_Period_of_Content:
Time_Period_Information:
Range_of_Dates/Times:
Beginning_Date: 1913
Ending_Date: 1995
Source_Currentness_Reference: GLO Texas General Land Office
Source_Scale_Denominator: 24000
Type_of_Source_Media: Paper
Source_Citation_Abbreviation: GLO
Process_Step:
Process_Description:
Lines were manually transferred/scaled from Texas General Land Office county survey maps onto U.S.G.S. 7.5 minute quadrangle maps using cultural features, such as roads, fences, and water features for reference. The survey lines and related annotation were then digitized from the quad maps. Attribute information was keyed from the GLO Abstract of Original Land Titles and then imported into the dataset using the abstract number (ANUM) as the primary key.
Process_Date: 1995
Not just Texas
Here is one example of fun GIS, the local county:
the kinda red line are property lines and the darker lines are I guess "PLSS" lines in 40 acre squares.
There is another set of lines (blue) shifted a few hundred feet NW that can be found through the state land board, LOL. As you might expect none of them are very close.:-D
It's not just Texas...
I have a good deal of patience when I encounter a home owner trying to figure out his lines using the GIS. This is especially true if they realize the futility and call me. When it's people that should know better I get worked up. Lucky for me I haven't run into a Surveyor doing it yet.
Locally I had a City Engineer reject a permit because the GIS lines showed a building inside the set-back. I walked him through GIS versus surveyed and he relented. I still run into property owners in disputes (in the same City) because they built the fence where the City showed them the (GIS) lines were. One even showed me the note where the 'line is 15 inches north of the sidewalk'.
I do my best to remain patient. It's getting harder...
They are a fantastic "go by" to begin looking at them as they are superimposed on aerial photography. Past that, it's time to d/l the notes and get a shovel.
It's just a cartoon folks, step away from the GIS.
It's a visual index of (some of) the data at the GLO. It's a finding tool for research, not a map.
It's not just Texas...
I'm with you. An uniformed layman/landowner/home owner, yeah their ignorance is somewhat explainable. A land surveyor, they should know about the problems with GIS and NEVER use the GIS as the basis of surveying boundaries. Someday maybe we will get close. At this time no way. GIS is a nice tool and the technology is there. Until the public is prepared to pay to convert the crap to reliable data..........................................(preaching to the choir)
GIS=Get It Surveyed
Especially since the background "original" survey info is off of a friggin Tobin map.
To simplify the above:
In case any Texas surveyor hasn't realized this, the original survey lines shown on the GLO GIS are not very accurate. Don't use them for any purpose other than sort of telling you where a corner *might* be within perhaps 300 or 400 feet (if you're lucky).
I started work on a project today in which the assignment was to figure out which of two somewhat recent surveys had correctly located a land grant line originally run in 1882. The two different surveys showed locations that differed by about 80 ft. horizontally, one being about 80 ft. North of the other.
After preliminary work on the ground, it's obvious that the original corner is in fact more than 80 ft. South of the more northerly position. Enough original evidence from the 1882 survey remains that this isn't a "maybe". So, what went wrong? After examining the Texas GLO GIS, I'm pretty sure that one of the surveyors just lifted the location shown in the GIS and based both the map and metes and bounds description upon that picture. This placed more than half of the tract surveyed in another land grant entirely and fueled an entirely needless lawsuit between the adjoining land owners.
Best practice is to consider the GLO GIS to be less reliable than rural addresses in Google Maps. If you're stuck trying to put original survey lines on the ground from the GIS, you might as well throw in the towel and find another area of endeavor.
> I started work on a project today in which the assignment was to figure out which of two somewhat recent surveys had correctly located a land grant line originally run in 1882. The two different surveys showed locations that differed by about 80 ft. horizontally, one being about 80 ft. North of the other.
>
> After preliminary work on the ground, it's obvious that the original corner is in fact more than 80 ft. South of the more northerly position. Enough original evidence from the 1882 survey remains that this isn't a "maybe". So, what went wrong? After examining the Texas GLO GIS, I'm pretty sure that one of the surveyors just lifted the location shown in the GIS and based both the map and metes and bounds description upon that picture. This placed more than half of the tract surveyed in another land grant entirely and fueled an entirely needless lawsuit between the adjoining land owners.
Naw, you need to emphasize the drama of the license-threatening situations that wrongful reliance on GIS will create. The position of the land grant line shown on the GIS got a survey map out the door without spending the two or three extra days that actually surveying it would have required, but after all the dust settles, I'm going to guess that the responsible surveyor will want to rethink that lifestyle choice.
