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File format

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Enter options from the command line interface for the -o command. Examples: bbox no-quantization precision=0.001. Click to see all options.
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Basemap options

Your data will be displayed using the Mercator projection.

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Simplification

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Prevent small polygon features from disappearing at high simplification. Keeps the largest ring of multi-ring features.
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Treat x, y values as Cartesian coordinates on a plane, rather than as longitude, latitude coordinates on a sphere.

Method

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Simplified lines remain within a set distance of original lines. Good for thinning dense points, but spikes tend to form at high simplification.
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Lines are simplified by iteratively removing the point that forms the least-area triangle with two adjacent points.
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Points located at the vertex of more acute angles are preferentially removed, for a smoother appearance.
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CADforum

Mapshaper @ CADforum.cz is a viewer and editor for map data

View, edit and convert polygons, lines and points to Shapefile, GeoJSON, TopoJSON, KML or SVG. This software is licensed under MPL 2.0.

Drop or paste files here or select from a folder

Shapefile, GeoJSON, TopoJSON, KML and CSV files are supported
Files can be gzipped or in a zip archive

Quick import

Drop or paste files here to import with default settings
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