The role of the surveyor was defined famously by Thomas M. Cooley, chief justice of the Supreme Court of the State of Michigan, in an essay first published in the Michigan Engineering Society Journal late in the 19th century.* In "The Judicial Function of Surveyors," Judge Cooley offered two rules for the surveyor when property boundaries are in dispute. The first rule is "to search for original monuments or the place where they were originally located"¦" The second rule is, when original monuments are no longer discoverable, "the question of location becomes one of evidence merely." State statutes should not direct the surveyor "to locate or establish a corner, as the place of the original monument, according to some inflexible rule." Instead, the surveyor "must inquire into all the facts"¦ always keeping in mind, first, that neither his opinion nor his survey can be conclusive upon parties concerned, [emphasis added] and second, that courts and juries may be required to follow after the surveyor over the same ground, and that it is exceedingly desirable that he govern his action by the same lights and the same rules that will govern theirs."
Judge Cooley summarizes by observing that "[s]urveyors are not and cannot be judicial officers, but in a great many cases they act in a quasi-judicial capacity with the acquiescence of the parties concerned"¦" To put it another way, the culmination of the surveyor's work is an opinion expressed by the plan he produces and by the marks or monuments he sets on the ground. He has no official judicial function or authority, but his opinion will be accepted most of the time by the property owners affected until or unless it is overturned by a court.
Surveyor JudgmentIt is clear that there are several principles for the surveyor to consider before arriving at an opinion as to the location of a property boundary. In construing a deed she must consider the superiority of calls for monuments over distance and direction; and direction over distance except where distance would be more reliable, but she must first be satisfied that the monuments she has recovered in her field survey are the original called-for monuments. She must attempt to find original intent of the grantor and grantee when the description is ambiguous or inadequate. She must also consider both the general and the particular descriptions of a deed and make a judgment when there is a contradiction between the two. Another principle is that any ambiguity in the description should be resolved in favor of the grantee. All these judgments require careful study and thoughtful consideration and may well be contradicted by another surveyor and may be overturned as a result of litigation. Williams and Onsrud, in "What Every Lawyer Should Know About Title Surveys,"  explain it this way: "If a court upheld the surveyor's evaluation of the evidence in the example, it is because the surveyor arrived at a comprehensive and well-reasoned answer rather than because he arrived at the theoretically correct answer. "¦ [T]here are no "true' answers waiting to be discovered, only well-reasoned answers."
Professional CooperationBoundary disputes occur when owners of adjacent land disagree on the location of the line between their properties. This may be because of their own impressions of where the line should be, but more often it is because a surveyor for one of the owners has defined the line contrary to the understanding or belief of the other owner. If the second owner cannot be convinced by the first neighbor's surveyor, he will hire his own surveyor hoping to support his own understanding or belief. Logic suggests that the second surveyor will come to the same conclusion as the first surveyor as to the location of the line. But history and experience show otherwise. Each surveyor will come to his or her own conclusions based on a study of the deeds involved and the conditions on the ground. When there are ambiguities, contradictions or errors in the record or as evidenced in conditions on the ground, surveyors must weigh the evidence and arrive at their own conclusions. Williams and Onsrud explain that "[s]urveyors occasionally disagree on the proper location of a boundary line not necessarily because one surveyor measures better than the other, but more commonly because each surveyor has weighed the evidence differently and has formed different opinions." 
Two surveyors coming to differing "well-reasoned answers" have a regulatory obligation in some jurisdictions to seek a common understanding. For instance, the standards of Massachusetts state: "In the event of substantial disagreement with the work of another surveyor, contact the other surveyor and investigate the disagreement."  Besides a regulatory obligation, surveyors have an ethical obligation to reconcile their differences in order to meet their social responsibilities. "In the event a property surveyor "¦ disagrees with the work of another property surveyor, it is the duty of that surveyor to inform the other surveyor of such fact."  By following a regulatory directive and by recognizing their professional duty, two surveyors with differing conclusions in their neighboring surveys are in a position to avoid or settle a dispute between abutting property owners. It is a dispute that could lead to expensive and protracted litigation. Unfortunately, a misplaced concern for their clients' interests, ego and a reluctance to yield to another's opinion, or a concern for a supposed professional liability exposure often mitigate against cooperation between surveyors with contradictory opinions. All too often the result is litigation wherein a court will arrive at its own conclusions regarding the disputed boundary.
Each professional surveyor has a duty to his client and an equal duty to his client's neighbor. Both surveyors ought to recognize they are in a position to keep peace in the neighborhood-if only they can reach a collective "well-reasoned answer."
*This essay was reprinted in the July-Sept. 1953 issue of Surveying And Mapping, a journal of the American Congress on Surveying and Mapping, and in "The Surveyor in Court," an ACSM-published collection of articles first appearing in Surveying And Mapping. It is currently available online at a number of state surveying society websites.