simplify_geometries.py.md

Simplify geometries

Simplify geometries of a polygon using a method and a tolerance

Requirements & Installation

See README.md

Usage

Arguments

Argument	Summary	Description	Optional	Default	Type
-h/--help	display help	display detailed usage and examples	✔
--inputlayer	path to input layer	path to the input layer to be split (format gpkg, geojson, kml, shp)			string
--method	method	simplification method:			integer
		0 - distance (Douglas-Peucker)
		1 - snap to grid
		2 - area (Visvalingam)
--tolerance	tolerance	tolerance of simplification (0 = no simplification)			integer/float
--outfile	output file (absolute)	path to output file (format gpkg, geojson, kml, shp)			string

Examples

See tests.tar.gz for sample files to run tests on

Simplify USA mainland using snap-to-grid method with a tolerance of 0.25

python3 simplify_geometries.py \
    --inputlayer $PWD/../tests/usa-mainland.geojson \
    --method 1  \
    --tolerance 0.25 \
    --outfile $PWD/../tests/usa-mainland-simplified.geojson

Original: 73,916 vertices

Simplified: 1,115 vertices

Output

Write the generated simplified polygon to the provided output file.

Documentation

https://docs.qgis.org/3.10/en/docs/user_manual/processing_algs/qgis/vectorgeometry.html#simplify