simplify-geojson

    1.0.4 • Public • Published

    simplify-geojson

    Apply Ramer–Douglas–Peucker line simplification to GeoJSON features or feature collections in JS or on the CLI.

    NPM

    This module uses https://github.com/seabre/simplify-geometry for the simplification and wraps it in a interface for easily simplifying GeoJSON.

    Install

    npm install simplify-geojson
    

    Usage

    CLI

    cat data.geojson | simplify-geojson -t 0.01

    Tolerance is specified by either -t or --tolerance and is a number in degrees (e.g. lat/lon distance). 1 degree is roughly equivalent to 69 miles. the default is 0.001, which is around a city block long.

    JS

    var simplify = require('simplify-geojson')
    var simplified = simplify(geojson, tolerance)

    geojson can be any of the following:

    • Feature with a LineString
    • Feature with a MultiLineString
    • Feature with a Polygon
    • Feature with a MultiPolygon
    • FeatureCollection with any of the above

    All segments in any of the supported types will be simplified (including holes in polygons, for instance).

    Examples

    Convert a CSV with lat/lon columns into geojson, then simplify that geojson, then open it in geojson.io (CSV is from my GPS logger and was my bike commute this morning):

    npm install simplify-geojson geojsonio-cli csv2geojson -g
    curl https://raw.github.com/maxogden/simplify-geojson/master/test-data/oakland-route.csv | \
      csv2geojson --lat "LATITUDE N/S" --lon "LONGITUDE E/W" --line true | \
      simplify-geojson -t 0.001 | \
      geojsonio

    Simplify alaska's border outline and count the number of lines of the simplified geojson output (tweak -t to see how it affects length):

    curl https://rawgit.com/johan/world.geo.json/master/countries/USA/AK.geo.json | \
      simplify-geojson -t 0.01 | \
      wc -l

    Contributing

    Contributors welcome! Please read the contributing guidelines before getting started.

    License

    BSD-2-Clause

    Install

    npm i simplify-geojson

    DownloadsWeekly Downloads

    3,969

    Version

    1.0.4

    License

    BSD-2-Clause

    Unpacked Size

    7.64 kB

    Total Files

    7

    Last publish

    Collaborators

    • maxogden
    • ungoldman