Unfortunately, mapshaper can't run in
this web browser
For best results, try
Add a file
Enter options from the command line interface for the -o command. Examples: "bbox" "no-quantization" "precision=0.001"
prevent shape removal
Prevent small polygon features from disappearing at high simplification. Keeps the largest ring of multi-ring features.
use planar geometry
Interpret x, y values as Cartesian coordinates on a plane, rather than longitude, latitude coordinates on a sphere.
Simplified lines remain within a set distance of original lines. Good for thinning dense points, but spikes tend to form at high simplification.
Visvalingam / effective area
Lines are simplified by iteratively removing the point that forms the least-area triangle with two adjacent points.
Visvalingam / weighted area
Points located at the vertex of more acute angles are preferentially removed, for a smoother appearance.
Mapshaper is an editor for map data
Drop or paste files here or
from a folder
Shapefile, GeoJSON, TopoJSON, DBF and CSV files are supported
Files can be loose or in a zip archive
Drop or paste files here to import with default settings
detect line intersections
Detect line intersections, including self-intersections, to help identify topological errors in a dataset.
Fix topology errors by snapping together points with nearly identical coordinates. This option does not apply to TopoJSON files.
Enter options from the command line interface. Examples: "no-topology" "encoding=big5"
0 line intersections