Simplify Geospatial Data Online — GeoJSON, Shapefile, KML, GPX and more
Geometry simplification reduces the number of vertices in your vector data, shrinking file sizes and speeding up rendering — without losing the overall shape of features. Use these free browser-based tools to simplify GeoJSON, Shapefile, KML, GeoPackage, or GPX files instantly.
What is buffering?
Geometry simplification removes redundant vertices from lines and polygons while preserving the overall shape. The most widely used algorithm is Douglas–Peucker: it iteratively removes points that fall within a given distance (the tolerance) of the straight line between their neighbours. A higher tolerance removes more points and produces a coarser result; a lower tolerance keeps more detail.
These tools use GDAL's ogr2ogr simplification implementation, which applies the Douglas–Peucker algorithm to each geometry independently. The tolerance is expressed in degrees of latitude/longitude (since the data is in WGS 84). For most web map use cases, a tolerance of 0.0001° (roughly 10 m) gives good results.
Simplification does not merge or dissolve features — it only reduces the vertex count within each feature's geometry. Attributes are preserved unchanged.
Common use cases
Web map performance
Reduce large polygon or line datasets to a fraction of their size before publishing to a web tile layer or vector tile service.
Small-scale display
Generate a lower-resolution version of a dataset for overview maps where fine detail would be invisible anyway.
File size reduction
Shrink GeoJSON or Shapefile files before sharing by email, uploading to a CMS, or committing to version control.
Faster spatial analysis
Speed up overlay, buffer, and intersection operations by reducing vertex counts before running computationally expensive operations.
GPX track smoothing
Remove GPS noise from recorded tracks to produce a cleaner line for display or distance calculation.
How to use
- 1
Upload your file — drop a GeoJSON, Shapefile (ZIP), KML, GeoPackage, or GPX file onto the upload zone.
- 2
Set the tolerance — enter a value in degrees. For web maps try 0.0001; for country-scale data try 0.001 or higher.
- 3
Download the result — the simplified file is returned in the same format with vertex counts and file size reduced.
Supported formats
| Format | Best for |
|---|---|
| GeoJSON | Best for web maps and JavaScript tooling. Single UTF-8 text file, no auxiliary files. |
| Shapefile | Best for legacy GIS software. Upload as a ZIP containing .shp, .dbf, and .prj. |
| KML | Best for Google Earth and Google Maps sharing. |
| GeoPackage | Best for modern GIS workflows. Single SQLite file supporting multiple layers. |
| GPX | Best for GPS tracks and routes. Works with Garmin, Strava, and most outdoor navigation apps. |
Frequently asked questions
What tolerance value should I use?
For web maps at city scale, try 0.0001° (≈ 10 m). For regional or national datasets displayed at small scales, try 0.001° (≈ 100 m) or 0.01° (≈ 1 km). Start low and increase until you see unacceptable shape distortion.
Will simplification break topology between shared borders?
The Douglas–Peucker algorithm simplifies each geometry independently, so shared borders between adjacent polygons may no longer align exactly after simplification. If topology preservation is critical, use a topology-aware simplifier such as GRASS v.generalize.
Does simplification affect attributes?
No — all attribute columns are preserved unchanged. Only the geometry (vertex coordinates) is modified.
Can I simplify a GPX track?
Yes — GPX tracks are treated as line geometries. Simplification removes redundant trackpoints while preserving the overall route shape, which also removes some GPS noise.
What is the tolerance unit?
The tolerance is in degrees of WGS 84 longitude/latitude, which is the native coordinate system for all supported formats. At mid-latitudes, 0.0001° ≈ 11 m.