An interesting case study in measuring one's own land.<p>I have a former working background in surveying calcs and mapping, and have also been long considering embarking upon a similar DIY project for my own property.<p>One aspect I note, having spent quite some time at it myself, is that there is somewhat of an art to the generation of accurate topographical contour lines from a set of manually surveyed points. Both in what points to survey, and in how to treat the points. The reference term here is TIN or Triangulated Irregular Network. Automated software does a fair job of building TINs, but the resulting contour lines can in some areas represent detail or features that don't really exist.<p>For example in the author's contour maps under the "Finally, The Mapping" section, much of the leftmost half is particularly sparse in measured points and as a result, the contour lines have interpolated some wacky humps-and-hollows across that half of the land, at least some of which probably don't exist in reality. (Technically speaking, long skinny triangles = not ideal, particularly at large scale; and separately, another key word or concept to look into is that of topographical "breaklines")<p>Ultimately, the specific arrangement of triangles in the TIN defines how the contour lines will be drawn. Good starting data is half the equation, and the other half is how you TIN it.