geojson_vi 2.0.0

GeoJSON package for Dart and Flutter developers to create, read, search, update and delete the geospatial data interchange format (GIS data).

example/README.md

Examples

Create GeoJSON object

  final map = {
    'type': 'Point',
    'coordinates': [105.77389, 21.0720414]
  };

  final jsonString =
      '{"type": "Point", "coordinates": [105.78070163726807, 21.067921688241626]}';

  final polygonCoordinates = [
    [
      [104.765625, 20.468189],
      [106.545410, 20.468189],
      [106.545410, 21.596150],
      [104.765625, 21.596150],
      [104.765625, 20.468189]
    ]
  ];

  // Creating a GeoJSON object from data without knowing its type
  final pointFromMap = GeoJSON.fromMap(map);

  // Creating GeoJSONPoint object from JSON string already know its type
  final pointFromJSON = GeoJSONPoint.fromJSON(jsonString);

  // Creating GeoJSONGeometry object from data without knowing its type
  final geometryFromMap = GeoJSONGeometry.fromMap(map);

  // Creating GeoJSONPoint object from JSON string already know its type
  final geometryFromJSON = GeoJSONPoint.fromJSON(jsonString);

  // Creating GeoJSONPoint object from coordinates data
  final pointFromCoordinates = GeoJSONPoint([105.77389, 21.0720414]);

  // Creating a GeoJSONFeature object
  final feature = GeoJSONFeature(
    GeoJSONPoint([105.780701, 21.067921]),
    properties: {
      'title': 'Hanoi University of Mining and Geology',
      'url': 'http://humg.edu.vn',
    },
  );

  // Creating GeoJSONFeatureCollection object
  final featureCollection = GeoJSONFeatureCollection([]);
  featureCollection.features.add(feature);

  // Creating more GeoJSONFeature
  final polygon = GeoJSONPolygon(polygonCoordinates);
  final polygonFeature = GeoJSONFeature(polygon);
  featureCollection.features.add(polygonFeature);

Read and Write the GeoJSON file

  final path = '../test/test_resources/data.geojson';
  final newPath = '../test/test_resources/data_new.geojson';
  final geoJSONFromFile = await GeoJSON.load(path);
  await geoJSONFromFile.save(newPath);

Demo

import 'package:geojson_vi/geojson_vi.dart';

void main() {
  final featureCollection = GeoJSONFeatureCollection([]);
  final point = GeoJSONPoint([105.7743099, 21.0717561]);
  final feature = GeoJSONFeature(point, properties: {
    'marker-color': '#7e7e7e',
    'marker-size': 'medium',
    'marker-symbol': 'college',
    'title': 'Hanoi University of Mining and Geology',
    'department': 'Geoinformation Technology',
    'address':
        'No.18 Vien Street - Duc Thang Ward - Bac Tu Liem District - Ha Noi, Vietnam',
    'url': 'http://humg.edu.vn'
  });
  featureCollection.features.add(feature);
  final pos1 = [105.7771289, 21.0715458];
  final pos2 = [105.7745218, 21.0715658];
  final pos3 = [105.7729125, 21.0715358];
  final lineString = GeoJSONLineString([pos1, pos2, pos3]);
  featureCollection.features.add(GeoJSONFeature(lineString, properties: {
    'stroke': '#7e7e7e',
    'stroke-width': 2,
    'stroke-opacity': 1,
    'title': 'Vien St.'
  }));
  final p01 = [105.7739666, 21.0726795]; // The first position
  final p02 = [105.7739719, 21.0721991];
  final p03 = [105.7743394, 21.0721966];
  final p04 = [105.7743310, 21.0725269];
  final p05 = [105.7742564, 21.0726120];
  final p06 = [105.7741865, 21.0726095];
  final p07 = [105.7741785, 21.0726746];
  final p08 = [105.7739666, 21.0726795]; // The last position
  final linerRing = [p01, p02, p03, p04, p05, p06, p07, p08];
  featureCollection.features.add(
    GeoJSONFeature(
      GeoJSONPolygon([linerRing]),
      properties: {
        'stroke': '#555555',
        'stroke-width': 2,
        'stroke-opacity': 1,
        'fill': '#ab7942',
        'fill-opacity': 0.5,
        'title': "HUMG's Office"
      },
    ),
  );
  print(featureCollection.toJSON());
}