geojson-precision

Remove meaningless precision from your GeoJSON. If your coordinates go out to 7+ digits, you are probably misrepresenting your data. Most scenarios in which GeoJSON is useful (i.e. web-related applications) do not require survey-grade precision, and a higher value is placed on a compact file size. Trimming the precision of coordinates can greatly reduce file size, while removing the appearance of fake high precision.

Install

npm install [-g] geojson-precision

API

.parse(geojson, precision)

geojson is a valid GeoJSON object, and can be of type Point, LineString, Polygon, MultiPoint, MultiPolygon, MultiLineString, GeometryCollection, Feature, or FeatureCollection. If you are unsure whether or not your GeoJSON object is valid, you can run it through a linter such as geojsonhint.

precision is a positive integer. If your specified precision value is greater than the precision of the input geometry, the output precision will be the same as the input. For example, if your input coordinates are [10.0, 20.0], and you specify a precision of 5, the output will be the same as the input.

Example use:

const gp = require("geojson-precision");
 
let trimmed = gp.parse({
        "type": "Point",
        "coordinates": [
          18.984375,
          57.32652122521709
        ]
      }, 3);
 

trimmed will now look like this:

{
    "type": "Point",
    "coordinates": [
       18.984,
       57.326
    ]
}

.parse() can also be used directly, for example:

const gp = require("geojson-precision");
 
let trimmed = gp({ ... }, 3);
 

CLI

Geojson-precision can also be used via the command line when installed globally (using -g).

Parameters

precision (-p)

A positive integer specifying coordinate precision

extras precision (-e)

A positive integer specifying extra coordinate precision for things like the z value when the coordinate is [longitude, latitude, elevation].

input

An input GeoJSON file

output

An output GeoJSON file

Example use

geojson-precision -p 4 input.json output.json

Inspiration

Concepts, ideas, etc borrowed to various degrees from:

• wellknown
• LilJSON

License

MIT