# GeoJSON Simplifier

Reduce the number of points in GeoJSON lines and polygons while keeping their shape. Paste a Feature, FeatureCollection or geometry, choose a tolerance in degrees, and the tool applies the Ramer-Douglas-Peucker algorithm of the Turf library, keeps all properties and returns compact GeoJSON. Great for shrinking GPS tracks, boundaries and map data before publishing them on the web or sending them to an API.

## Frequently asked questions

### How does the simplification work?

The tool uses the Ramer-Douglas-Peucker algorithm as implemented in Turf, which removes points that lie closer than the tolerance to the line through their neighbors. Large bends stay, while dense runs of nearly straight points are thinned out.

### What does the tolerance mean?

The tolerance is a distance in degrees, the unit of the coordinates. At the equator 0.001 degrees is roughly 111 meters and 0.0001 about 11 meters, and higher values remove more points. You can choose from 0 to 1 degree, and the default is 0.001.

### What does high quality do?

By default a fast radial distance pass runs before Douglas-Peucker and drops points that are very close together. With high quality turned on, that pass is skipped, which is slower but can keep a slightly more faithful shape.

### Which geometries are simplified?

LineString, MultiLineString, Polygon and MultiPolygon are simplified, including those inside a GeometryCollection. Points and MultiPoints are returned unchanged.

### Are polygons kept valid?

Polygon rings always keep at least four positions, so a ring is never reduced to a line. With a very high tolerance small rings can still change shape strongly, so check the result before using it.

### Are my properties preserved?

Yes. Feature properties, ids and the structure of the input are kept, and only the coordinate arrays of lines and polygons get shorter. The output is compact JSON without indentation.

### What input does the tool accept?

Valid GeoJSON with longitude and latitude in WGS84 degrees: a FeatureCollection, a Feature or a bare geometry. Polygon rings must be closed, and coordinates must be numbers within the valid range.

### How large can the input be?

Up to 5 MiB of GeoJSON and 10,000 features per request. For larger datasets, split the collection into parts or use a desktop GIS.

### Does the tool round my coordinates?

No. The coordinates that remain are copied exactly as they were in the input. To shrink the file further, round coordinates to six decimal places, which still resolves about 0.1 meters.

### Why did nothing change?

With a tolerance of 0, or with data whose points are already farther apart than the tolerance, no point qualifies for removal. Increase the tolerance step by step until the result is small enough while the shape still looks right.

Your ad here?

[Email us](mailto:hi@dennn.is?subject=Advertising%20on%20OneClick%20Pro)

[Ad The agent-ready plugin suite for WordPress.](https://sleekwp.com/?ref=oneclickpro)