Question on topographic maps (area reference)?
When looking for the area reference on a topographic map, is the northings reference rounded to the closest number?
Sort of. It depends on two things you are looking for. Precision and accuracy. Precision is essentially how many places after the decimal is it rounded to. This is also known as tolerance.
Accuracy is it’s correctness to within a certain tolerance.
A topographic map is very accurate and usually has a scale of 1:25000. The map or the top sheet of that quadrangle series should tell you it’s accuracy and precision.
They are usually rounded to degrees, minutes and seconds so it is really quite accurate and precise. The numbers listed are probably more accurate than the stake in the ground or other USGS benchmark. Look for the brass markers embedded in the ground. You will find them on dams, piers and other structures that are solid and immovable.
Also, since the earth is always changing, they were accurate at the time of the last verification.
Sort of. It depends on two things you are looking for. Precision and accuracy. Precision is essentially how many places after the decimal is it rounded to. This is also known as tolerance.
Accuracy is it’s correctness to within a certain tolerance.
A topographic map is very accurate and usually has a scale of 1:25000. The map or the top sheet of that quadrangle series should tell you it’s accuracy and precision.
They are usually rounded to degrees, minutes and seconds so it is really quite accurate and precise. The numbers listed are probably more accurate than the stake in the ground or other USGS benchmark. Look for the brass markers embedded in the ground. You will find them on dams, piers and other structures that are solid and immovable.
Also, since the earth is always changing, they were accurate at the time of the last verification.
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