Geo Valley

A Promise-based GeoJSON validation library for TypeScript.

• Validates GeoJSONs of the following types: Feature, FeatureCollection, Geometry, Geometry Collection.
• Optimized for Node.js TypeScript.
• Customizable output.

Documentation

• User Guide: Learn how to start using Geo Valley.
• Examples: See usage examples.
• API: See API.

User Guide

Install geo-valley using the npm package manager:

$ npm install geo-valley

Import the library at the top of your file:

import * as GV from 'geo-valley'

Examples

Say you have a parsed FeatureCollection myGeojson:

const myGeometry = {
    type: 'LineString',
    coordinates: [
        [102.0, 0.0], [103.0, 1.0], [104.0, 0.0]
    ]
}

const myGeojson = {
    type: 'FeatureCollection',
    features: [
        {
            type: 'Feature',
            geometry: myGeometry,
        }
    ]
}

Start validating your GeoJSON:

async function main() {
    const result = await GJ.isFeatureCollection(myGeojson)
    console.log(result)
    // undefined

    const result = await GJ.isFeatureCollection.bool(myGeojson)
    console.log(result)
    // true
}

If you use fp-ts, you can get the output as type Either<string, void>:

import { Either, isLeft, left } from 'fp-ts/lib/Either'

// ...

async function main() {
    const result = await GJ.isGeometry.either(myGeometry)

    if (isLeft(result)) {
        console.log('Errors:', left(result))
    } else {
        console.log('Valid')
    }
}

API

Each function takes one argument—the object you want to validate.

Each function returns undefined if the object is valid, or string[] if the object is invalid.

Each function has a bool variant that will simply return true for valid or false for invalid.

.isValid(geojson)

Checks whether an object is a valid GeoJSON.

Returns: Promise<string[] | undefined>

Variants:

• isValid.bool(geojson): Promise<boolean>
• isValid.either(geojson): Promise<Either<string[], void>>

.isGeojson(input)

Checks whether an object is a valid GeoJSON.

Returns: Promise<string[] | undefined>

Variants:

• isGeojson.bool(input): Promise<boolean>
• isGeojson.either(input): Promise<Either<string[], void>>

.isFeature(input)

Checks whether an object is a valid Feature.

Returns: Promise<string[] | undefined>

Variants:

• isFeature.bool(input): Promise<boolean>
• isFeature.either(input): Promise<Either<string[], void>>

.isFeatureCollection(input)

Checks whether an object is a valid FeatureCollection.

Returns: Promise<string[] | undefined>

Variants:

• isFeatureCollection.bool(input): Promise<boolean>
• isFeatureCollection.either(input): Promise<Either<string[], void>>

.isGeometry(input)

Checks whether an object is a valid Geometry.

Returns: Promise<string[] | undefined>

Variants:

• isGeometry.bool(input): Promise<boolean>
• isGeometry.either(input): Promise<Either<string[], void>>

.isGeometryCollection(input)

Checks whether an object is a valid GeometryCollection.

Returns: Promise<string[] | undefined>

Variants:

• isGeometryCollection.bool(input): Promise<boolean>
• isGeometryCollection.either(input): Promise<Either<string[], void>>

.isPoint(input)

Checks whether an object is a valid Point geometry.

Returns: Promise<string[] | undefined>

Variants:

• isPoint.bool(input): Promise<boolean>
• isPoint.either(input): Promise<Either<string[], void>>

.isMultiPoint(input)

Checks whether an object is a valid MultiPoint geometry.

Returns: Promise<string[] | undefined>

Variants:

• isMultiPoint.bool(input): Promise<boolean>
• isMultiPoint.either(input): Promise<Either<string[], void>>

.isLineString(input)

Checks whether an object is a valid Line String geometry.

Returns: Promise<string[] | undefined>

Variants:

• isLineString.bool(input): Promise<boolean>
• isLineString.either(input): Promise<Either<string[], void>>

.isMultiLineString(input)

Checks whether an object is a valid MultiLine String geometry.

Returns: Promise<string[] | undefined>

Variants:

• isMultiLineString.bool(input): Promise<boolean>
• isMultiLineString.either(input): Promise<Either<string[], void>>

.isPolygon(input)

Checks whether an object is a valid Polygon geometry.

Returns: Promise<string[] | undefined>

Variants:

• isPolygon.bool(input): Promise<boolean>
• isPolygon.either(input): Promise<Either<string[], void>>

.isMultiPolygon(input)

Checks whether an object is a valid MultiPolygon geometry.

Returns: Promise<string[] | undefined>

Variants:

• isMultiPolygon.bool(input): Promise<boolean>
• isMultiPolygon.either(input): Promise<Either<string[], void>>

.isBox(input)

Checks whether an object is a valid Bounding Box.

Returns: Promise<string[] | undefined>

Variants:

• isBox.bool(input): Promise<boolean>
• isBox.either(input): Promise<Either<string[], void>>

.isPosition(input)

Checks whether an object is a valid Position.

Returns: Promise<string[] | undefined>

Variants:

• isPosition.bool(input): Promise<boolean>
• isPosition.either(input): Promise<Either<string[], void>>

License

LGPL-3

Credits

Thanks to:

• This guide on setting up my first-ever NPM package.
• The original package author.