Boundary Surveying


Boundary surveying is the branch of land surveying in which a licensed surveyor establishes the boundaries of a parcel of land on the ground.  In all states in the U.S. a surveyor must be licensed by the state as a Professional Land Surveyor before he or she can be retained by a client to establish their boundaries.

Types of Boundary Surveys.  There are two basic types of boundary surveys: Original Surveys and Retracement Surveys.  An original survey creates new boundaries.  A retracement survey is simply a survey of a parcel of land that has already been created by an original survey.  The image at the right shows a parcel of land between two streets that was divided into 5 parcels or “Lots”.  When the surveyor first created these lots and drew the plan the survey would have been an original survey.  Assume that all 5 lots were sold to different people  Assume you own lot number 3 and can’t find the corners of your lot.   When you hire a surveyor to set your lot corners, the surveyor will perform a retracement survey.  It cannot be an original survey because your parcel is already in existence.  there can only be one original survey, the survey that originally created the 5 lots.

In a retracement survey, the new surveyor must locate the boundaries at their original locations, i.e., the locations where the original surveyor set the original corners on the ground.  Because physical monuments that mark boundary corners become lost or disturbed over time, and because the new surveyor is required by law to set the corners at exactly the same place the original surveyor set them, retracement surveying is often difficult, time consuming and expensive. When original corners are lost or disturbed the retracement surveyor must know and follow certain legal rules which will affect the corner locations.  If the correct sequence of legal rules is not followed, the new corners may not actually represent their true original locations and both the property owner and surveyor may be subject to liability. If you own a parcel of land and you need a survey in order to know where your lot corners are located on the ground you will probably require a retracement survey.

How a typical survey is performed.  The first thing that a surveyor does before going into the field it to obtain copies of the deed of the parcel to be surveyed and the deeds of all abutting properties. If the parcel to be surveyed is in a city block, the surveyor will most likely have to get copies of all of the deeds in the block.  This is because the location of the streets making up the block are fixed on the ground and the sum of all of the deed distances between the streets may not add up to the actual distance between the streets.  If the survey is not in an urban area the surveyor will still need copies of the applicable deeds and plans pertaining to the description of the property to be surveyed and the abutting properties.

Once the surveyor has all of the deeds the surveyor will go out into the field in order to look for the physical evidence called-for in the deeds.  For example consider the image below which shows a division of land into 6 lots. If you owned parcel 2-A and wanted to know where your lot corners were located on the ground you would need to retain the services of a land surveyor. In order for a surveyor to be able to establish your corner locations the surveyor would obtain a copy of the plan shown in the image and a copy of your deed. Your deed would presumably reference the plan as the survey from which your parcel of land was created. In order for a surveyor to locate your boundaries on the ground the surveyor must be able to find enough original physical evidence (monuments) on the ground called-for on the plan and/or your deed. Notice that the plan calls for a number of monuments such as “DH in BLDR” and “C.B.” These notations refer to physical evidence that existed on the ground at the time of the original survey. If these monuments are still in existence and they are undisturbed it should be possible to survey the property. If the monuments have disappeared, the survey could turn out to be difficult. It is important to understand that, in general, the only monuments that control boundary locations are the monuments that are called for in the deed or a plan referenced in the deed. Just because there are monuments on the ground which appear to be near boundary corners does not mean that they can be used for the purpose of surveying a particular parcel of land.


Traverse Lines.  Because many property lines run along fences or walls which act as obstructions making it difficult to measure along the lines, it is usually not convenient for surveyors to try to measure exactly along the boundaries.  Surveyors solve this problem by running “Traverse Lines”.  Traverse lines are simply offset survey lines that a surveyor runs where there is a clear line-of-sight (no obstructions) between the traverse corners.  The traverse lines are shown as red dashed lines on the image at the right.  The traverse corners are numbered from 1 to 5.  You can see that the traverse lines are in the general vicinity of the boundary lines but they are located so as to miss obstructions.  Notice that line 3-4 was located in order to clear both buildings.  Once the traverse lines have been measured, the traverse points (numbered 1-5) can be used to set the actual lot corners.  The short dashed blue lines, for example 5-D, show the connection between the traverse corner and the boundary corner.


Lot Surveys

We perform many surveys of small lots located in cities. These surveys present their own unique set of challenges. In many cities the streets are well monumented with stone markers. These monuments fix the street lines which abut private property so they are usually the first place a surveyor looks when beginning a survey of private property. Many of these monuments were set during the 19th and early 20th centuries. The monuments are usually located at street intersections near the back edge of the sidewalk. In many cases the sidewalks have been replaced and the original stone monuments destroyed or covered over during the construction of the new sidewalks. In such cases it may be necessary to extend the survey for several city blocks until a sufficient number of monuments have been recovered.