KML and GeoJSON

This page shows you how to render geographic data in KML and GeoJSON formats, using GMUKMLParser and GMUGeoJSONParser, in conjunction with GMUGeometryRenderer. KML and GeoJSON are popular formats for rendering geographic data such as points, lines, and polygons.

The following screenshot shows some example KML data rendered on a map:

Prerequisites and notes

The GMUKMLParser and GMUGeoJSONParser are part of the Maps SDK for iOS Utility Library. If you haven't yet set up the library, follow the setup guide before reading the rest of this page.

For the full code sample, see the sample apps on GitHub.

Rendering KML data

To render KML data on a map, create a GMUKMLParser with the path to a KML resource (KML_Sample.kml in this example). Then, create a GMUGeometryRenderer passing the GMUKMLParser instance. Finally, call GMUGeometryRenderer.render(). The following code example shows rendering KML data on a map:

Swift

import GoogleMapsUtils

class KML: NSObject {
  private var mapView: GMSMapView!

  func renderKml() {
    guard let path = Bundle.main.path(forResource: "KML_Sample", ofType: "kml") else {
      print("Invalid path")
      return
    }

    let url = URL(fileURLWithPath: path)

    let kmlParser = GMUKMLParser(url: url)
    kmlParser.parse()

    let renderer = GMUGeometryRenderer(
      map: mapView,
      geometries: kmlParser.placemarks,
      styles: kmlParser.styles
    )

    renderer.render()
  }
}
      

Objective-C

@import GoogleMapsUtils;

@implementation KML {
  GMSMapView *_mapView;
}

- (void)renderKml {
  NSString *path = [[NSBundle mainBundle] pathForResource:@"KML_Sample" ofType:@"kml"];
  NSURL *url = [NSURL fileURLWithPath:path];
  GMUKMLParser *parser = [[GMUKMLParser alloc] initWithURL:url];
  [parser parse];
  GMUGeometryRenderer *renderer = [[GMUGeometryRenderer alloc] initWithMap:_mapView
                                                                geometries:parser.placemarks
                                                                    styles:parser.styles];
  [renderer render];
}

@end
      

Rendering GeoJSON data

To render GeoJSON data on a map, create a GMUGeoJSONParser with the path to a GeoJSON resource (GeoJSON_sample.kml in this example). Then, create a GMUGeometryRenderer, passing the GMUKMLParser instance. Finally, call GMUGeometryRenderer.render(). The following code example shows rendering GeoJSON data on a map:

Swift

import GoogleMapsUtils

class GeoJSON {
  private var mapView: GMSMapView!

  func renderGeoJSON() {
    guard let path = Bundle.main.path(forResource: "GeoJSON_sample", ofType: "json") else {
      return
    }

    let url = URL(fileURLWithPath: path)

    let geoJsonParser = GMUGeoJSONParser(url: url)
    geoJsonParser.parse()

    let renderer = GMUGeometryRenderer(map: mapView, geometries: geoJsonParser.features)
    renderer.render()
  }
}
      

Objective-C

@import GoogleMapsUtils;

@implementation GeoJSON {
  GMSMapView *_mapView;
}

- (void)renderGeoJSON {
  NSString *path = [[NSBundle mainBundle] pathForResource:@"GeoJSON_sample" ofType:@"json"];
  NSURL *url = [NSURL fileURLWithPath:path];
  GMUGeoJSONParser *parser = [[GMUGeoJSONParser alloc] initWithURL:url];
  [parser parse];
  GMUGeometryRenderer *renderer = [[GMUGeometryRenderer alloc] initWithMap:_mapView
                                                                geometries:parser.features];
  [renderer render];
}

@end