Visibility Index: What does "Use height interpolation" mean and do?

zoran-cuckovic / QGIS-visibility-analysis

Quantum GIS plugin for visibility analysis

GNU General Public License v3.0

72 stars 17 forks source link

Visibility Index: What does "Use height interpolation" mean and do? #57

Closed Bernd-Vogelgesang closed 3 years ago

Bernd-Vogelgesang commented 3 years ago

First, thanx a lot for this crazy fast plugin! A coffee will soon be on it's way. As I would like to use the Visibility index for a project, I need to be able to describe it's functionality for the documentation. In the docs, I could not find any mentioning of the default option to use height interpolation. So I kindly ask you to elaborate a bit on the why and how of the this option. Cheers, Bernd

zoran-cuckovic commented 3 years ago

Hello ! You can read on height interpolation here : https://landscapearchaeology.org/2018/qgis-visibility-analysis-algorithm/. In a nutshell, lines of sight pass between pairs of pixels, an the terrain height is deduced (interpolated) by taking into account both values. Otherwise we can only check the nearest pixel, which is faster but less precise.