The Fatal Flaws of GIS

The first part of this article appeared in the July issue.

Having written the title, I must hasten to add that this is not an attack on GIS, but an attempt to clarify the issues between it and land boundary surveying. GIS has already proven an excellent tool in a wide range of applications and that is as it should be. Just as the technology of human cloning has set the ethics and morality of that technology in the forefront, so GPS and GIS have disrupted the domain of land surveying. Like all disruptive technologies, it can be used for good or ill. To date, the good flowing from GIS usage is so preponderant that, were it not for the gravity of its potential for damage to property rights, I would be embarrassed to point it out at all. But, GIS needs a little guidance and restriction.

Theoretically there is no conflict between the practice of land surveying and GIS: the law is clear in regard to who it has endowed with the authority to identify boundaries. But practically, there is real conflict: GIS practitioners are publishing soft and hard copy documents that have all the look and feel of a survey plat without a proper survey behind it. This is misleading to all but the most informed. The resolution of this conflict can only be realized by education and legislation.
Another issue for the land surveyor is demonstrated by a recent posting on a surveyors' message board where there appeared the following under a thread entitled "I was talking to my GIS friend at the county…" It states, "He said they were talking about having surveyors establish deci-meter to centimeter coordinates on all property corners in several sections that were proving difficult to establish with deed work alone. They have already done a great service to local surveyors by paying to have all the section corners located with centimeter coordinates. They don't need any corners set in these sections but they do need accurate property corner values. Aside from the question of whether it is even legal for us to do that work to those relaxed standards, is it a good idea?"
The responses posted to that question demonstrated little clarity of thought or unity in attitude about the questions raised. I don't believe that was due to ignorance or apathy on the part of the responders. Rather it was clear evidence that we are dealing with a disruptive technology. For us to properly respond to this disruption we must be certain we understand both GIS and land surveying and how they relate to each another.
In this article I want to go right to the roots of land surveying. Once we get those clearly in mind, we will hold GIS up next to surveying and point out the differences and discover the flaws in GIS which prevent it from obsoleting the licensed land surveyor. GIS will become a tool for the surveyor, but it can never rise above that. Finally I want to suggest some actions that seem appropriate for the difficulties GIS is posing for us.

The Chain of Authority
In our democratic republic, the authority to enact and administer law comes from the same source as the rights those laws are designed to protect. This is the essence and the genius of our system. In the case of property rights, the people have endowed their representatives by election as the guardians of their rights. They, in turn, have created the office of licensed land surveyor and endowed that office with authority to see to the accurate protection of property rights in the field, on the ground where it really matters most.
Let's talk about rights briefly. A thorough understanding of rights is the most empowering resource we have in this effort to really understand our profession vis a vis GIS.

The Nature of Property Rights
First, consider a stone. Does it have the right to take its space in the earth? What then of a poplar tree-has it the right to push aside the stone, to mine the ground for its sustenance, and to inhabit its portion of the world? Then think of the beaver. Has it not the right to harvest the poplar and construct a home for itself and offspring? What is the source of the obvious rights of these things? They are inherent and intrinsic in their very beings. Their rights are not some attachment or appendage, but an integral part of their very existence. This is easily proven by taking away the right of the stone to occupy space-to do that you must annihilate the stone. To remove the tree rights of the beaver is to render him homeless and assign him to rapid extinction. The right to occupy a place in the world is perhaps the most fundamental human right. To deny that right is to degrade the human to less than a stone. This is why boundary issues are fraught with profound emotion and sometimes accompanied by violence-they threaten the very essence of our being. The word "right" simply denotes this crucial aspect of our existence and a property right is just a legal term to describe this basic human right.
The reason there are land surveyors can be logically and historically traced back to this most basic right. The ancient body of law that has grown up around property boundary issues declares the supremacy of these matters. Consequently land surveying is all about the protection and perpetuation of that right.

The Nature of the Land Surveyor
Common law has recognized the basics of land boundary location and perpetuation. We discussed those in the "Our Paradigm Problem" article last month. The principles of common law have been codified into statutes. Furthermore, the licensed land surveyor has been created, authorized and charged with this location and perpetuation stewardship at the place where boundaries actually exist-on the ground. Thus, both boundaries and their duly authorized stewards are the offspring of law. Because of this, the decisions of the licensed land surveyor have the weight of law, and the judicious decisions of the licensed land surveyor will almost always survive exacting inspection of the courts.

The Nature of Land Boundaries

A land boundary is an invisible, immovable, and perpetual legal delineation separating the property rights of the adjoiners. Land boundaries are not created by measurement, but by the legal activities of the owner. Measurement is only a convenience for description and perpetuation of the boundary and is always ancillary to the essence of the line. To illustrate this, it is only necessary to consider a property description devoid of measurement: e.g., … thence easterly to the biggest boulder on the West bank Conner Creek, thence along said bank to the influx of Whipple Creek, …
Just as a birthday cake becomes meaningless without a birthday, so measurements without the law are nothing more than an exercise of skill.

A Boundary Is More a Matter of Law Than of Measurement
The essence of a retracement survey is the search for evidence. The surveyor looks in the record, uses his measuring skills to position himself in the vicinity of the boundary and then searches for evidence on the ground and in the memories of neighbors. This is primarily a legal activity: it is the building of a case defensible in court if necessary. The objective is to accurately mark the original location. Accuracy in this activity is defined by how close he comes to marking the original corner, not how precisely he replicates a description on the ground. A surveyor who does not understand this will measure and create pincushion corners-a direct muddling of the boundary he is charged to detect and defend. Just as an aside, I fear that the speed and precision of our new measuring tools often cause us to ignore the fundamental nature of what it is we are doing and we violate our stewardship by driving pins with great precision but embarrassing inaccuracy.

The Weights of Evidence
We can infer a lot about the legal nature of the land surveyor's work and begin to see the fatal flaws in GIS by looking at the hierarchy of boundary evidence. When the court has difficulty with conflicting evidence, such as a description that doesn't match the monuments, it uses a well defined hierarchy to assign weights to evidences based on the nature of the evidence. This is a fascinating thing to a surveyor as it runs directly opposite to our usual, everyday activities. This hierarchy is nonetheless very well established, agreed upon by the legal and historical pundits of land boundaries and often cited in trials. Here it is: keep in mind that this list runs from the most powerful to the weakest form of evidence of boundary location:

o Unwritten Title
o Senior Rights
o Call for a prior survey
o Call for a natural monument
o Call for an artificial monument
o Distance
o Direction
o Area
o Coordinates

To illustrate how this list is applied, we can consider a well-known example. When the description calls a distance and bearing to a monument and the monument is extant, the monument rules-all the measurements in the world will not suffice to wear out the power of a known fixed monument silently flaunting its authority. Coordinates as the weakest form of evidence will bother most of us in today's GPS world. The fact is however, that obtaining a property description is still done by measuring distances and angles and the coordinates are usually derived therefrom, which makes coordinates a secondary kind of evidence to bearing and distance. The actual effective order of this list will vary somewhat on a case by case basis depending on individual circumstances.

The Nature of Surveying

Now let's take a look at a summary of what we know about the surveyor and surveying.

A. All the basic activities of the boundary surveyor are prescribed by law.
B. The law tells the surveyor what to do and how to do it.
C. The law tells the surveyor how to weigh evidence for remarking boundaries.
D. Surveying is a legal activity, defined and mandated by statute and common law.
E. Only the licensed surveyor is authorized to declare boundaries.
F. Descriptions are not boundaries, but reports of measurements.
G. A boundary cannot be established by measurement alone.
H. A survey document is a legal document: endowed by law with the force of law.

The Fatal Flaws of GIS

GIS cannot be used for delineation of property rights for many reasons, many of which are insurmountable. Here they are:

A. Data in GIS are derived from property descriptions and are secondary data
B. Land boundaries are described by coordinates: the weakest kind of evidence
C. GIS systems possess no judiciousness: unable to cope with conflicting evidence
D. GIS can never address unwritten title
E. GIS contains no senior/junior rights information
F. GIS workers have no legal status/ authority with respect to boundaries
G. Using GIS for the location of boundaries is not a legally defined activity
H. GIS maps can be de facto counterfeits of legal survey documents
Even if we were to reach the point where GIS can describe land boundaries accurately, such descriptions will none-theless still be descriptions-secondary evidence of boundary location. There is no physical way to bring the monuments into an information system, thus there will always be a demand for land surveyors to go out on the ground and verify the data. The basic point here is that a legal description is not a land boundary. There are always problems with the connection between the two. About 85% of the time, the description will be accurate enough that driving stakes per the description is good enough. In other words, a GIS system based on property descriptions will be wrong about 15% of the time.


1. GIS data is not survey quality and cannot legally be used to produce survey documents.
2. Surveyors can use GIS anyway they want to, they have the authority.
3. Inasmuch as people use GIS to try to replace a legal survey they are practicing surveying without a license.
4. GIS workers may gain de facto authority with the public by continuing to perform survey work. This will create havoc similar to poorly executed surveys.
5. Institutions and agencies want survey quality for some of their activities and are contracting with surveyors in an effort to fix that problem. These entities may then issue documents with implied or explicit certification as to survey quality.
To honor our trust as stewards of land boundaries, surveyors need to protect themselves and the data they acquire. If we let GIS dilute the authority vested in us by permitting GIS to issue documents masquerading as survey plats, we will have broken our trust with the public and with one another.


My recommendations are that we work in two major areas: education and legislation.

Work with the GIS people at the highest level. Surely they are aware of these issues. Our top people should be in dialog with them so that our two industries are working in harmony and self-policing as much as possible.
We need to educate GIS users. The Axioms and Corollaries published last month in the "Our Paradigm Problem" article were specifically designed as a starting point for education of all land boundary and especially GIS workers. A one-page flyer on the counter in every County Recorder's office could be a good beginning. Such flyers should be approved and endorsed by the state surveyors' association.

Here are a couple rough drafts of laws that may help us with the GIS problem. I am stating them in very brief form as I only want to convey the concepts not directly suggest wording.
1. Schematic or graphic data which appears to be equivalent to a land survey plat or map must be accompanied by a certification on the face of the document as to the quality of the data. This certification shall state either A) "This property map is of land survey quality and is suitable for such use." or (B) "This property map is NOT of land survey quality and is NOT suitable for such use." Failure to comply with this requirement shall constitute practicing land surveying without a license.
2. Those responsible for the issuance of hard or soft copy documents showing land ownership or easement with angular or length dimensions shall correctly state the accuracy of such in regard to their relationships with actual boundaries on the ground and are liable for redress of parties who suffer loss by their dependence upon such data when such data is in fact less accurate than that stated.
The second one is basically a statement of existing common law that is currently applied by the courts to surveyors. Here it is generalized to cover all documents that may have the color of survey quality. This kind of legislation should not be difficult to obtain since it arises from the same circumstances that current statutes require certification on survey plats and charts. These suggestions are admittedly in very rough form but I believe the approach is correct.

My intent has been to identify and clarify the fundamentals of the issues swirling around GIS and land surveying and hopefully to help put the ongoing dialog in our profession in sharper focus. Perhaps our most important feat of the next decade will be to completely abandon our defensive posture and take the leadership that the duly authorized guardians of property rights should and must take.

Jackson Pemberton has training in Physics, Mathematics, Business Administration, and Land Surveying. He has professionally written articles on the subjects of the U.S. Constitution and land surveying. His experience includes 30 years of computer systems analysis and programming. He is currently looking for original Public Land Survey System (PLSS) corners and developing software to facilitate the complex task of finding such corners. You can read his writings on land surveying and peruse his legal research on boundary and corner law at and you can contact him at

Editor's Note: Please note that the opinions expressed herein are those of the author and do not necessarily reflect the beliefs of the staff of GITC America. If you wish to comment on Mr. Pemberton's views, please write to:

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