Geospatial feature service Web APIs with support for GeoJSON and OGC API Features clients for Dart.

Features

✨ New: Updated with latest geobase version 0.2.1 and geocore version 0.9.0 based on Dart SDK 2.17.

Key features:

• Client-side data source abstraction for geospatial feature service Web APIs
• Implementations to read geospatial features
  • GeoJSON features from Web APIs or files
  • OGC API Features based services (partial support)

The client-side support for the OGC API Features standard is not complete, however key functionality of Part1 of the standard is supported.

Package

The package requires at least Dart SDK 2.17, and it supports all Dart and Flutter platforms.

To use, add the dependency in your pubspec.yaml:

dependencies:
  geodata: ^0.9.0

The package contains also following mini-libraries, that can be used to import only a certain subset instead of the whole geodata library:

All the mini-libraries have dependencies to the equatable, geobase and geocore packages.

The geojson_client and ogcapi_features_client libraries depends also on the http package.

Usage

This sample shows to read GeoJSON features from a web resource using a HTTP fetcher, and from a local file using a file fetcher.

Please see other examples too.

import 'package:geodata/geojson_client.dart';

Future<void> main(List<String> args) async {
  // read GeoJSON for earthquakes from web using HTTP(S)
  print('GeoJSON features from HTTP');
  await _readFeatures(
    geoJsonHttpClient(
      location: Uri.parse(
        'https://earthquake.usgs.gov/earthquakes/feed/v1.0/summary/'
        '2.5_day.geojson',
      ),
    ),
  );
}

Future<void> _readFeatures(BasicFeatureSource source) async {
  // read features with error handling
  try {
    // get items or features from a source, maximum 5 features returned
    final items = await source.itemsAll(limit: 5);

    // do something with features, in this sample just print them out
    for (final f in items.collection.features) {
      print('Feature with id: ${f.id}');
      print('  geometry: ${f.geometry}');
      print('  properties:');
      for (final key in f.properties.keys) {
        print('    $key: ${f.properties[key]}');
      }
    }
  } on ServiceException<FeatureFailure> catch (e) {
    print('Reading GeoJSON resource failed: ${e.failure.name}');
    if (e.cause != null) {
      print('Cause: ${e.cause}');
    }
    if (e.trace != null) {
      print(e.trace);
    }
  } catch (e, st) {
    print('Reading GeoJSON resource failed: $e');
    print(st);
  }
}

Authors

This project is authored by Navibyte.

More information and other links are available at the geospatial repository from GitHub.

License

This project is licensed under the "BSD-3-Clause"-style license.

Please see the LICENSE.