Go.geojson is a package for encoding and decoding GeoJSON into Go structs.
Supports both the json.Marshaler and json.Unmarshaler
interfaces as well as sql.Scanner for directly scanning PostGIS query results.
The package also provides helper functions such as UnmarshalFeatureCollection
, UnmarshalFeature
and UnmarshalGeometry
.
go get github.com/paulmach/go.geojson
import "github.com/paulmach/go.geojson"
-
go.geojson supports both the json.Marshaler and json.Unmarshaler interfaces as well as helper functions such as
UnmarshalFeatureCollection
,UnmarshalFeature
andUnmarshalGeometry
.// Feature Collection rawFeatureJSON := []byte(` { "type": "FeatureCollection", "features": [ { "type": "Feature", "geometry": {"type": "Point", "coordinates": [102.0, 0.5]}, "properties": {"prop0": "value0"} } ] }`) fc1, err := geojson.UnmarshalFeatureCollection(rawFeatureJSON) fc2 := geojson.NewFeatureCollection() err := json.Unmarshal(rawJSON, fc2) // Geometry rawGeometryJSON := []byte(`{"type": "Point", "coordinates": [102.0, 0.5]}`) g, err := geojson.UnmarshalGeometry(rawGeometryJSON) g.IsPoint() == true g.Point == []float64{102.0, 0.5}
-
g := geojson.NewPointGeometry([]float64{1, 2}) rawJSON, err := g.MarshalJSON() fc := geojson.NewFeatureCollection() fc.AddFeature(geojson.NewPointFeature([]float64{1,2})) rawJSON, err := fc.MarshalJSON()
-
row := db.QueryRow("SELECT ST_AsGeoJSON(the_geom) FROM postgis_table) var geometry *geojson.Geometry row.Scan(&geometry)
-
A geometry can be of several types, causing problems in a statically typed language. Thus there is a separate attribute on Geometry for each type. See the Geometry object for more details.
g := geojson.UnmarshalGeometry([]byte(` { "type": "LineString", "coordinates": [ [102.0, 0.0], [103.0, 1.0], [104.0, 0.0], [105.0, 1.0] ] }`)) switch { case g.IsPoint(): // do something with g.Point case g.IsLineString(): // do something with g.LineString }
GeoJSON Features can have properties of any type. This can cause issues in a statically typed language such as Go. So, included are some helper methods on the Feature object to ease the pain.
// functions to do the casting for you
func (f Feature) PropertyBool(key string) (bool, error) {
func (f Feature) PropertyInt(key string) (int, error) {
func (f Feature) PropertyFloat64(key string) (float64, error) {
func (f Feature) PropertyString(key string) (string, error) {
// functions that hide the error and let you define default
func (f Feature) PropertyMustBool(key string, def ...bool) bool {
func (f Feature) PropertyMustInt(key string, def ...int) int {
func (f Feature) PropertyMustFloat64(key string, def ...float64) float64 {
func (f Feature) PropertyMustString(key string, def ...string) string {