Perfect circles do not exist. Idealisms are not real. That is another reason that Math , as Godel showed, is not complete, not always applicable, and occ. wrong.

Einstein a great empirical visual thinker said this. To the extent math is accurate it's useful. To the extent it's precise, it's not real. This einsteinian concept easily proves and is proven by the disparities between Maps and the features they pretend to show.

Mercator projections are not real. It distorts features. Either.

For instance if we look at 90 Deg map on the point directly below us, over a globe all the edges are distorted. If we move over 100 miles, worse. What we've mapped before is distorted and what we see 90 below us is NOT the same as 100 Miles East or west. Nor is the southern edge nor north edge.

So we do successive corrections and get an approximation. But it's never quite right. The flat map paper we lay down to read is Not exact either. Imposing that same 90 deg 2D flat map problem. See? Accurate, useful but assuming real goes too far.

As is said, what you measure depends by Einsteinian, true relativity, cannot be correct. There is NO absolute measure. There is NO absolute space/time. That space on the maps is a measure of that highly likely, by proven Relativity.

Thus ALL the flat maps we use are Wrongl! because they impose the Flat 2d, 90 deg but not spherical map on paper. National geo Maps are flat. The Earth is round, thus ALL OUR maps are not quite right.

So our maps' errors show the relativity of measuring methods. Missed that, dintcha!!