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Add a file
Enter options from the command line interface for the -o command. Examples: bbox no-quantization precision=0.001. Click to see all options.
choose output directory
save to clipboard
Your data will be displayed using the Mercator projection.
prevent shape removal
Prevent small polygon features from disappearing at high simplification. Keeps the largest ring of multi-ring features.
use planar geometry
Treat x, y values as Cartesian coordinates on a plane, rather than as 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, KML and CSV files are supported
Files can be gzipped 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.
Enter options from the command line interface. Examples:
snap no-topology encoding=big5
. Click to see all options.
0 line intersections