View of a tesseroid (spherical prism) in a geocentric coordinate system. Red planes show the six bounding surfaces of a tesseroid: two parallels, two meridians, and two concentric spheres.
This figure is used in the Tesseroids (http://tesseroids.leouieda.com) software documentation.
Created using Inkscape (https://inkscape.org).
Other file formats are available in the Github repository (https://github.com/leouieda/tesseroid-figures).