If you build CAD, GIS, or numerical simulation software, an "annulus" rarely shows up as a teaching exercise. It shows up as the gap between a pipe and its insulation, the paved shoulder around a manhole cover, the buffer zone between two concentric road lanes, or the ring-shaped catchment you s...
Source: [Dev.to](https://dev.to/lizely/engineering-an-annulus-area-check-into-your-cad-and-gis-pipeline-3490)