As mentioned above, heat can affect measurement, and this is only one source of natural error.
Human sight and memory are both imperfect, which can lead to misreading or mistaken recording of field measurements. Personal error arises from the fact that the surveyor is only human. Even simple surveying tools like measuring tapes can be affected by ambient temperatures, resulting in a tape that is either longer or shorter than it should be. Instrumentation error results from actual imperfection in the manufacture of the surveying instrument itself, or from the surveyor’s initial adjustment when setting up the instrument. There are three broad categories of initial surveyor error: instrumental, personal, and natural. What are the sources of measurement error? Begin with the initial survey itself. Master everything from OSHA regulations, to high-tech safety equipment in this FREE Special Report: Construction Safety Topics That Can Save Lives. And to do that, we have to understand the sources of potential error and minimize as much as possible, while still having a useful model of the site in question. Knowing this to be true, however, we must take into account the effects of this inherent imperfection of measurements derived from the map. These are used only in relation to how well they approximate the real terrain or structure that they represent. No measurement, no map, no plan, no diagram. The most accurate map possible would be the territory, and thus would be perfectly accurate and perfectly useless.” – Neil Gaiman Photos: Trimble “The more accurate the map, the more it resembles the territory. Sources of Measurement Error-The Map is Not the Terrain Since there is an inherent error in any estimating earthwork calculation, the contractor must properly manage the resultant unknowns to ensure the success of the project. An accurate estimate of the earthwork volumes and areas is essential for a contractor to both submit an accurate bid that has the potential to win a contract and to properly manage the resources assigned to the project so that he shows a profit. But what was a matter of mystic philosophy to the Greeks is a matter of financial life or death for earthwork contractors. Pythagoras and other mathematicians determined those formulas that are still used to calculate the volumes of spheres and pyramids, as well as the areas of curve conic sections. Formulas and methods for determining the volumes and areas of regular shapes and surfaces go back at least as far as ancient Greece.
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