Precision Vs. Accuracy

Practicing GIS demands a nuanced understanding of the important differences between precision and accuracy.  Precision is how close measure values are to each other, basically how many decimal places are at the end of a given measurement.  Precision does matter.  Accuracy is how close a measure value is to the true value.  Accuracy matters too, but it’s best when measurements are both precise and accurate.

Failure to understand the tension between precision and accuracy can have profound negative effects on how one processes data, and the final outcome of geospatial analysis.