Does all this mean we have performed useless, inaccurate calculations in this course so far? Fortunately, that's not the case. An important feature of geometry columns is that the error they generate gets smaller when we work with smaller areas of the Earth. This means we can safely use geometry to work with single cities or counties because the error will be negligible.

To begin examining the differences between geometry and geography columns, we will start by calculating the length of a single bicycle route in San Francisco using the geometry column you know very well.