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How Accurate Are Boundary Surveys?

boundary survey accuracy

Maybe you would like to determine the exact size of a piece of land you intend to sell or purchase. Maybe you are preparing for construction, and would like to make certain you do not encroach on a neighboring property. Or perhaps you would like to settle a dispute – or prevent one from arising in the near or distant future. In all of these cases, you need a boundary survey.

What Is a Boundary Survey?

A boundary survey determines and illustrates the exact locations of a property’s legal boundaries. If you were to create a boundary survey of the nation of France, then the resultant map would be exactly France-shaped. If you were to create a boundary survey of your property, then its lines would contain 100 percent of the land you legally own – and not one square inch of land which falls outside of your possession.

How Is a Boundary Survey Created?

The creation of a boundary survey is a multifaceted process. First the surveyor reviews all available deeds: those of both the property they are surveying and the parcels surrounding it. Then the surveyor visits the parcel with their trusty theodolite – aka “total station,” which is a tripod-mounted device that allows its operator to take precision measurements. The surveyor will also carefully note any physical features which can mark boundary lines, such as bodies of water. Once all their research is complete, the surveyor prepares a full report detailing the parcel’s boundary lines and any other information that could prove relevant in the foreseeable future.

How Accurate Is a Boundary Survey?

We just said that a theodolite takes “precision measurements.” To be sure, precision and accuracy aren’t analogous concepts.

  • Accuracy reflects how close a measurement is to its actual value. If a boundary line is exactly 100 feet long, and the surveyor measures it as such, then their measurement is perfectly accurate.
  • Precision refers to how close two measurements of the same item are to one another. If a boundary line is 100 feet long, and the surveyor measures it as 99 feet, then the measurement is inaccurate. But if five more surveyors all measure the same boundary line as 99 feet, then their measurements are precise – i.e. consistent – yet still inaccurate.

As you may already have gathered, a boundary survey’s accuracy boils down to two variables: the quality of the equipment used to record it, and the skill of the surveyor handling said equipment.

Surveying equipment has become substantially more accurate over recent decades. Whereas historic surveyors once relied on 66-foot long chains to take measurements, they now utilize digital equipment with integral microprocessors, lasers and GPS. Compared to a 19th century compass, which had an angular precision of 1 degree, a modern theodolite can achieve angular precision of 1/3600 degrees (i.e. 1 second).

Make no mistake: even the most technologically sophisticated equipment is capable of random and systematic errors. Environmental conditions such as temperature, humidity and barometric pressure can influence delicate machinery. Likewise, human error can produce wildly inaccurate results.

This underscores the necessity of hiring an experienced surveyor. They will not make rookie mistakes. They’re familiar with all the environmental factors which can impact accuracy, and overcome them to ensure that their boundary survey adheres to the maximum allowable Relative Positional Precision for an ALTA/NSPS Land Title Survey: 2 cm (0.07 feet) plus 50 parts per million (based on the direct distance between the two corners being tested). (Note that certain circumstances will result in survey measurements for which the maximum allowable Relative Positional Precision may be exceeded.)

To reiterate, a boundary survey is allowed to have 0.1128′ (2cm + 50 parts per million) margin of error. In simpler terms, a modern boundary survey is extraordinarily accurate. You can rest assured the one you commission will reflect the positions of your boundaries with virtually flawless accuracy.

Do you need a boundary survey in Minnesota, North Dakota or South Dakota? Set yourself up for success. Contact Compass Consultants today to schedule service, and rest assured that our expert surveyors and state-of-the-art equipment will produce accurate results you can truly rely on.