geojson-random-shift v0.0.1

geojson-random-shift

Randomly Shift Coordinates in a GeoJSON

install

npm install geojson-random-shift

basic usage

import randomShift from "geojson-random-shift";

const geojson = {
  "type": "Feature",
  "properties": {},
  "geometry": {
    "type": "Polygon",
    "coordinates": [
        [
            [30.0, 10.0],
            [40.0, 40.0],
            [20.0, 40.0],
            [10.0, 20.0],
            [30.0, 10.0]
        ]
    ]
  }
};

randomShift(geojson);
{
  "type": "Feature",
  "properties": {},
  "geometry": {
    "type": "Polygon",
    "coordinates": [
      [
        [
          29.999999951435843,
          10.000000087415803
        ],
        [
          40.000000086127606,
          39.99999994918626
        ],
        [
          19.999999944247676,
          40.00000008301613
        ],
        [
          10.000000031702344,
          19.99999990515823
        ],
        [
          29.999999951435843,
          10.000000087415803
        ]
      ]
    ]
  }
}

advanced usage

specifying distance threshold

You can specify a range of how much a coordinate should move. By default a coordinate will shift 0.0000001 degrees.

// each coordinate in the geojson must move between 10 and 100 degrees
randomShift(geojson, { range: [10, 100] });

containing to the world

By default points do not move outside of the traditional world bounding box of -180, -90, 180, 90. You can turn off this check for a minor speedup:

randomShift(geojson, { contain: false });

debug_level

You can change the debug level, which will log more information:

randomShift(geojson, { debug_level: 10 });

mutate

By default, geojson-random-shift clones the input to prevent mutation. If you don't care about saving the original geojson, you can turn this off for a big speed up.

randomShift(geojson, { mutate: true });