GeoJSON for Kotlin

geojson-kotlin is a Kotlin implementation of the GeoJSON specification (RFC 7946).

Usage

Add a dependency on geojson-kotlin to start using GeoJSON in your project.

implementation("dev.haeusler.geojson-kotlin:geojson:1.1")

val featureCollection: FeatureCollection = FeatureCollection(
    features = listOf(
        Feature(
            geometry = Point(Position(102.0, 0.5)),
            properties = mapOf(
                "prop0" to "value0",
            )
        ),
        Feature(
            geometry = LineString(
                coordinates = listOf(
                    Position(102.0, 0.0),
                    Position(103.0, 1.0),
                    Position(104.0, 0.0),
                    Position(105.0, 1.0)
                )
            ),
            properties = mapOf(
                "prop0" to "value0",
                "prop1" to 0.0,
            )
        )
    )
)

Using geojson-kotlin with Moshi

The geojson-moshi artifact features a collection of json adapters to serialize/deserialize GeoJSON using Moshi.

implementation("dev.haeusler.geojson-kotlin:geojson-moshi:1.1")

To use, supply an instance of GeoJsonAdapter when building your Moshi instance.

val moshiInstance = Moshi.Builder()
    // etc...
    .add(GeoJsonAdapter())
    .build()

And then serialize or deserialize your objects:

val adapter = moshiInstance.adapter(Feature::class.java)

val feature = Feature(
    geometry = Point(Position(102.0, 0.5)),
    properties = mapOf("prop0" to "value0")
)

val featureJson: String = adapter.toJson(feature)

val featureFromJson: Feature? = adapter.fromJson(featureJson)

Alternatively, you can also use the convenience extension functions to convert to JSON and back:

val featureJson = feature.toJson(indent = "  ", moshi = moshiInstance)
val featureFromJson = featureJson.toGeoJson(moshi = moshiInstance)

If you do not supply your own moshi instance, a new one will be created for you.