GeoJSON-Validation

A GeoJSON Validation Library
Check JSON objects to see whether or not they are valid GeoJSON. Validation is based off of the GeoJSON Format Specification revision 1.0

• Installation
• Usage
• Cli usage
• Api
• Testing
• Cavets

Installation

npm install geojson-validation

usage

var GJV = require("geojson-validation");
 
var validFeatureCollection = {
    "type": "FeatureCollection",
    "features": [
        {
            "type": "Feature",
            "geometry": {"type": "Point", "coordinates": [102.0, 0.5]},
            "properties": {"prop0": "value0"}
        },
        {
            "type": "Feature",
            "geometry": {
                "type": "LineString",
                "coordinates": [
                    [102.0, 0.0], [103.0, 1.0], [104.0, 0.0], [105.0, 1.0]
                ]
            },
            "properties": {
                "prop0": "value0",
                "prop1": 0.0
            }
        }
    ]
};
 
//simple test 
if(GJV.valid(validFeatureCollection)){
    console.log("this is valid GeoJSON!");
}
 
var invalidFeature =  {
    "type": "feature",
    "geometry": {
        "type": "LineString",
        "coordinates": [
            [102.0, 0.0], [103.0, 1.0], [104.0, 0.0], [105.0, 1.0]
        ]
    },
    "properties": {
        "prop0": "value0",
        "prop1": 0.0
    }
};
 
//test to see if `invalidFeature` is valid 
GJV.isFeature(invalidFeature, function(valid, errs){
    //log the errors 
    if(!valid){
       console.log(errs);
    }
});

CLI usage

first install gobally
npm install geojson-validation -g
Then you can use gjv to validate file such as
gjv file1 file2..
Or you can stream files to it cat file | gjv
gjv will either return a list of error or a valid if the files are indeed valid.

API

All Function return a boolean and take a JSON object that will be evalatued to see if it is a GeoJSON object, with the exception of define.

Arguments

• geoJSON - a JSON object that is tested to see if it is a valid GeoJSON object
• callback(boolean, errors) - boolean is whether or not the object is valid. errors is an array of validation errors for an invalid JSON object.

valid(geoJSON, callback)

Alias: isGeoJSONObject
Checks if an object is a GeoJSON Object.

isGeoJSONObject(geoJSON, callback)

Checks if an object is a GeoJSON Object.

isGeometryObject(geoJSON, callback)

Checks if an object is a Geometry Object

isPosition(array, callback)

Checks if an array is a Position

isPoint(geoJSON, callback)

Checks if an object is a Point

isMultiPointCoor(array, callback)

Checks if an array can be interperted as coordinates for a MultiPoint

isMultiPoint(geoJSON, callback)

Checks if an object is a MultiPoint

isLineStringCoor(array, callback)

Checks if an array can be interperted as coordinates for a LineString

isLineString(geoJSON, callback)

Checks if an object is a Line String

isMultiLineStringCoor(array, callback)

Checks if an array can be interperted as coordinates for a MultiLineString

isMultiLineString(geoJSON, callback)

Checks if an object is a MultiLine String

isPolygonCoor(array, callback)

Checks an array can be interperted as coordinates for a Polygon

isPolygon(geoJSON, callback)

Checks if an object is a Polygon

isMultiPolygonCoor(array, callback)

Checks if an array can be interperted as coordinates for a MultiPolygon

isMultiPolygon(geoJSON, callback)

Checks if an object is a MultiPolygon

isGeometryCollection(geoJSON, callback)

Checks if an object is a Geometry Collection

isFeature(geoJSON, callback)

Checks if an object is a Feature Object

isFeatureCollection(geoJSON, callback)

Checks if an object is a Feature Collection Object

isBbox(array, callback)

Checks if an object is a Bounding Box

Define(type, function)

Define a Custom Validation for the give type. type can be "Feature", "FeatureCollection", "Point", "MultiPoint", "LineString", "MultiLineString", "Polygon", "MultiPolygon", "GeometryCollection", "Bbox", "Position", "GeoJSON" or "GeometryObject".

The function is passed the object being validated and should return a string or an array of strings representing errors. If there are no errors then the function should not return anything or an empty array. See the example for more.

Define Example

Shout out to @VitoLau for the code for this example.

GJV = require("geojson-validation");
 
GJV.define("Position", function(position){
    //the postion must be valid point on the earth, x between -180 and 180 
    errors = [];
    if(position[0] < -180 || position[0] > 180){
        errors.push("the x must be between -180 and 180");
    }
    if(position[1] < -90 || position[1] > 90){
        errors.push("the y must be between -90 and 90");
    }
    return errors;
 
});
 
gj = {type: "Point", coordinates: [-200,3]};
//returns false 
GJV.isPoint(gj);

Testing

To run tests npm test
Test use mocha

Cavets

• Does not check ordering of Bouding Box coordinates
• Does not check Coordinate Reference System Objects
• Does not check order of rings for polygons with multiple rings