albertyw/albertyw.com

Geographic Geometry Simplification

geo-simplification

1675388483

[Douglas-Peucker Algorithm](https://en.wikipedia.org/wiki/Ramer%E2%80%93Douglas%E2%80%93Peucker_algorithm)

Simple explanation: Remove points P<sub>X</sub> that are less than the distance between the significant points P<sub>&lt;X</sub> and P<sub>&gt;X</sub>.

![Douglas-Peucker Visualization](/static/notes/20230203-0141-douglas-peucker.gif)

[Visvalingam Algorithm](https://en.wikipedia.org/wiki/Visvalingam%E2%80%93Whyatt_algorithm)

Simple explanation: Remove the point P<sub>X</sub> that forms the minimum area triangle with P<sub>X-1</sub> and P<sub>X+1</sub>.  Repeat until the area is above a threshold.

![Visvalingam Visualization](/static/notes/20230203-0141-visvalingam.png)