geojsonhint: complete, fast, standards-based validation for geojson

A lint tool for the GeoJSON standard. geojsonhint is written to the standard, with no missing or additional opinions about structure.

Thanks to jsonlint-lines, GeoJSON that is also not valid JSON can return informative, line-oriented parsing errors.

Specification

The basis of this tool is the published GeoJSON 1.0 specification. In the few cases where draft-geojson, the ietf-candidate version of GeoJSON, is more precise (for instance, the id property), the validator follows the draft spec as well.

API

errors = geojsonhint.hint(string or object, options)

Lint a file, given as a string or object. This call detects all aberrations from the GeoJSON standards and returns them as an array of errors. An example of the output:

[{
  "message": "\"features\" property should be an array, but is an object instead",
  "line": 1
}]

The options argument is optional and has one option: noDuplicateMembers. By default, geojsonhint will treat repeated properties as an error: you can set noDuplicateMembers to false to allow them. For instance:

geojsonhint.hint('{"type":"invalid","type":"Feature","properties":{},"geometry":null}', {
    noDuplicateMembers: false
});

The repeated type property in this input will be ignored with the option, and flagged without it.

Line Numbers

Note that the GeoJSON can be given as a string or as an object. Here's how to choose which input to use:

• string inputs receive line numbers for each error. These make errors easier to track down if the GeoJSON is hand-written.
• object inputs don't have line numbers but are evaluated faster, by up to 10x. GeoJSONHint is very fast already so unless you have identified it as a bottleneck in your application, don't prematurely optimize based on this fact.

For byte-minimalists, you can require('geojsonhint/object') to get a version of this library that bypasses jsonlint-lines and provides only the object interface.

use it

as a library

npm install --save geojsonhint

as a web library

curl https://raw.github.com/mapbox/geojsonhint/master/geojsonhint.js > geojsonhint.js

As a command-line utility

Install:

npm install -g geojsonhint

➟ geojsonhint
Usage: geojsonhint FILE.geojson

Options:
  --json  output json-formatted data for hints

➟ geojsonhint test.geojson
line 9, each element in a position must be a number

developing

Tests:

npm test

Building the browser version:

npm install -g browserify
make

See Also

• geojsonhint online
• grunt-geojsonhint does it as a Grunt task
• geojsonlint.com does this server-side
• GeoJSON-Validation is another node module for this.
• geojson-assert does it in assertion tests
• geojsonlint does it in an R package