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https://github.com/navibyte/geospatial

Geospatial data structures, tools and utilities for Dart and Flutter.
https://github.com/navibyte/geospatial

api dart geojson geometry geospatial gis ogc ogc-api spherical-geometry web-mercator wgs84 wkb wkt

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Geospatial data structures, tools and utilities for Dart and Flutter.

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README 

          
# :compass: Geospatial tools for Dart 



[![License](https://img.shields.io/badge/License-BSD%203--Clause-blue.svg)](https://opensource.org/licenses/BSD-3-Clause) [![Twitter URL](https://img.shields.io/twitter/url/https/twitter.com/navibyte.svg?style=social&label=Follow%20%40navibyte)](https://twitter.com/navibyte) [![style: very good analysis](https://img.shields.io/badge/style-very_good_analysis-B22C89.svg)](https://pub.dev/packages/very_good_analysis) 






**Geospatial** data structures, tools and utilities for 

[Dart](https://dart.dev/) and [Flutter](https://flutter.dev/) - coordinates,

geometries, feature objects, metadata, spherical geodesy, projections, tiling

schemes, vector data models and formats, and geospatial Web APIs.



Read the docs 👉 [geospatial.navibyte.dev](https://geospatial.navibyte.dev/)! 



[![Dart](https://img.shields.io/badge/dart-%230175C2.svg?style=for-the-badge&logo=dart&logoColor=white)](https://dart.dev/) [![Flutter](https://img.shields.io/badge/Flutter-%2302569B.svg?style=for-the-badge&logo=Flutter&logoColor=white)](https://flutter.dev/)



🗺️ [Roadmap 2025: The current state and candidate issues for the geobase package](https://github.com/navibyte/geospatial/issues/254).



✨ New (2025-03-11): The stable version 1.5.0 with [global grids](https://geospatial.navibyte.dev/v1/geobase/global-grids/), better WGS84 [projection](https://geospatial.navibyte.dev/v1/geobase/projections/) support and [unit conversions](https://geospatial.navibyte.dev/v1/geobase/unit-conversions/).



✨ New (2024-11-10): The stable release with [ellipsoidal geodesy functions](https://geospatial.navibyte.dev/v1/geobase/ellipsoidal-geodesy/) letting you calculate distances, bearings, destination positions and intermediate points along the Earth surface accurately.



✨ New (2024-07-26): The stable version 1.3.0 with centroid, polylabel, point-in-polygon and other cartesian 2D calculations enhanced - [read more](https://geospatial.navibyte.dev/v1/geobase/geometry-calculations/)!



## :package: Packages



[Dart](https://dart.dev/) code packages published at 

[pub.dev](https://pub.dev/publishers/navibyte.com/packages):



Code           | Package | Description 

-------------- | --------| -----------

:globe_with_meridians: [geobase](dart/geobase) | [![pub package](https://img.shields.io/pub/v/geobase.svg)](https://pub.dev/packages/geobase) | Geospatial data structures (coordinates, geometries, features, metadata), ellipsoidal and spherical geodesy, projections and tiling schemes. Vector data format support for [GeoJSON](https://geojson.org/), [WKT](https://en.wikipedia.org/wiki/Well-known_text_representation_of_geometry) and [WKB](https://en.wikipedia.org/wiki/Well-known_text_representation_of_geometry#Well-known_binary).

:earth_americas: [geodata](dart/geodata) | [![pub package](https://img.shields.io/pub/v/geodata.svg)](https://pub.dev/packages/geodata) | Geospatial feature service Web APIs with support for [GeoJSON](https://geojson.org/) and [OGC API Features](https://ogcapi.ogc.org/features/) clients.



## 📚 Documentation



Comprehensive guidance on how to use package and about

*Geospatial tools for Dart* is available on the

[geospatial.navibyte.dev](https://geospatial.navibyte.dev/) website.



Overview topics about *Geospatial tools for Dart*:



* [⛳️ Getting started](https://geospatial.navibyte.dev/v1/start/)

* [📖 Introduction](https://geospatial.navibyte.dev/v1/start/intro/)

* [💼 Code project](https://geospatial.navibyte.dev/reference/project/)

* [📚 API documentation](https://geospatial.navibyte.dev/reference/api/)



The [geobase](https://geospatial.navibyte.dev/v1/geobase/)

package documentation by chapters:



* [📍 Coordinates](https://geospatial.navibyte.dev/v1/geobase/coordinates/)

* [🧩 Simple geometries](https://geospatial.navibyte.dev/v1/geobase/geometry/)

* [📏 Geometry calculations](https://geospatial.navibyte.dev/v1/geobase/geometry-calculations/)

* [🔷 Geospatial features](https://geospatial.navibyte.dev/v1/geobase/features/)

* [📃 Vector formats](https://geospatial.navibyte.dev/v1/geobase/formats/)

* [🔵 Ellipsoidal geodesy](https://geospatial.navibyte.dev/v1/geobase/ellipsoidal-geodesy/)

* [📐 Spherical geodesy](https://geospatial.navibyte.dev/v1/geobase/spherical-geodesy/)

* [📅 Metadata](https://geospatial.navibyte.dev/v1/geobase/metadata/)

* [🌐 Global grids](https://geospatial.navibyte.dev/v1/geobase/global-grids/)

* [🗺️ Projections](https://geospatial.navibyte.dev/v1/geobase/projections/)

* [🔢 Tiling schemes](https://geospatial.navibyte.dev/v1/geobase/tiling-schemes/)

* [⚖️ Unit conversions](https://geospatial.navibyte.dev/v1/geobase/unit-conversions/)



The [geodata](https://geospatial.navibyte.dev/v1/geodata/)

package documentation by chapters:



* [🌐 GeoJSON Web API client](https://geospatial.navibyte.dev/v1/geodata/geojson-client/)

* [🌎 OGC API Features client](https://geospatial.navibyte.dev/v1/geodata/ogcfeat-client/)



## :sparkles: Features



Key features of the [geobase](https://pub.dev/packages/geobase) package:



* 🌐 geographic (longitude-latitude) and projected positions and bounding boxes

* 🧩 simple geometries (point, line string, polygon, multi point, multi line string, multi polygon, geometry collection)

* 📏 cartesian 2D calculations (centroid, polylabel, point-in-polygon, distance).

* 🔷 features (with id, properties and geometry) and feature collections

* 📐 ellipsoidal (*vincenty*) and spherical (*great circle*, *rhumb line*) geodesy tools, with ellipsoidal datum, [UTM](https://en.wikipedia.org/wiki/Universal_Transverse_Mercator_coordinate_system), [MGRS](https://en.wikipedia.org/wiki/Military_Grid_Reference_System) and ECEF (earth-centric earth-fixed) support

* 📅 temporal data structures (instant, interval) and spatial extents

* 📃 vector data formats supported ([GeoJSON](https://geojson.org/), [Newline-delimited GeoJSON](https://stevage.github.io/ndgeojson/), [WKT](https://en.wikipedia.org/wiki/Well-known_text_representation_of_geometry), [WKB](https://en.wikipedia.org/wiki/Well-known_text_representation_of_geometry#Well-known_binary)

)

* 🗺️ coordinate projections (built-in WGS84 based projections on geographic, geocentric, UTM and Web Mercator coordinates + external [proj4dart](https://pub.dev/packages/proj4dart) support)

* 🔢 tiling schemes and tile matrix sets (web mercator, global geodetic)

* ⚖️ unit conversions (angle, angular velocity, area, distance, speed and time)



Key features of the [geodata](https://pub.dev/packages/geodata) package:



* 🪄 Client-side data source abstraction for geospatial feature service Web APIs.

* 🌐 The [GeoJSON](https://geojson.org/) client to read features from static web resources and local files, supports also [Newline-delimited GeoJSON](https://stevage.github.io/ndgeojson/) data.

* 🌎 The [OGC API Features](https://ogcapi.ogc.org/features/) client to access metadata and feature items from a compliant geospatial Web API providing GeoJSON data.



Client-side support for the OGC API Features standard:



Standard part | Support in this package

------------- | -----------------------

[OGC API - Features - Part 1: Core](https://docs.ogc.org/is/17-069r4/17-069r4.html) | Supported for accessing metadata and GeoJSON feature collections.

[OGC API - Features - Part 2: Coordinate Reference Systems by Reference](https://docs.ogc.org/is/18-058r1/18-058r1.html) | Supported.

[OGC API - Features - Part 3: Filtering](https://docs.ogc.org/is/19-079r2/19-079r2.html)
[Common Query Language (CQL2)](https://docs.ogc.org/is/21-065r2/21-065r2.html) | Partially supported (conformance classes, queryables, features filter).



## :keyboard: Sample code



### Geodesy functions with geobase



*Ellipsoidal* and *spherical* geodesy functions to calculate distances etc.:



```dart

  final greenwich = Geographic.parseDms(lat: '51°28′40″ N', lon: '0°00′05″ W');

  final sydney = Geographic.parseDms(lat: '33.8688° S', lon: '151.2093° E');



  // How to calculate distances using ellipsoidal Vincenty, spherical

  // great-circle and spherical rhumb line methods is shown first.



  // The distance along a geodesic on the ellipsoid surface (16983.3 km).

  greenwich.vincenty().distanceTo(sydney);



  // By default the WGS84 reference ellipsoid is used but this can be changed.

  greenwich.vincenty(ellipsoid: Ellipsoid.GRS80).distanceTo(sydney);



  // The distance along a spherical great-circle path (16987.9 km).

  greenwich.spherical.distanceTo(sydney);



  // The distance along a spherical rhumb line path (17669.8 km).

  greenwich.rhumb.distanceTo(sydney);



  // Also bearings, destination points and mid points (or intermediate points)

  // are provided for all methods, but below shown only for great-circle paths.



  // Destination point (10 km to bearing 61°): 51° 31.3′ N, 0° 07.5′ E

  greenwich.spherical.initialBearingTo(sydney);

  greenwich.spherical.finalBearingTo(sydney);



  // Destination point: 51° 31.3′ N, 0° 07.5′ E

  greenwich.spherical.destinationPoint(distance: 10000, bearing: 61.0);



  // Midpoint: 28° 34.0′ N, 104° 41.6′ E

  greenwich.spherical.midPointTo(sydney);



  // Vincenty ellipsoidal geodesy functions provide also `inverse` and `direct`

  // methods to calculate shortest arcs along a geodesic on the ellipsoid. The

  // returned arc object contains origin and destination points, initial and

  // final bearings, and distance between points.

  greenwich.vincenty().inverse(sydney);

  greenwich.vincenty().direct(distance: 10000, bearing: 61.0);

```



### Geospatial data structures with geobase



As a quick sample, this is how geometry objects with 2D coordinate are created

using [geobase](https://pub.dev/packages/geobase):



Geometry    | Shape       | Dart code to build objects

----------- | ----------- | --------------------------

Point       |  | `Point.build([30.0, 10.0])`

LineString  |  | `LineString.build([30, 10, 10, 30, 40, 40])`

Polygon     |  | `Polygon.build([[30, 10, 40, 40, 20, 40, 10, 20, 30, 10]])`

Polygon (with a hole) |  | `Polygon.build([[35, 10, 45, 45, 15, 40, 10, 20, 35, 10], [20, 30, 35, 35, 30, 20, 20, 30]])`

MultiPoint  |  | `MultiPoint.build([[10, 40], [40, 30], [20, 20], [30, 10]])`

MultiLineString  |  | `MultiLineString.build([[10, 10, 20, 20, 10, 40], [40, 40, 30, 30, 40, 20, 30, 10]])`

MultiPolygon |  | `MultiPolygon.build([[[30, 20, 45, 40, 10, 40, 30, 20]], [[15, 5, 40, 10, 10, 20, 5, 10, 15, 5]]])`

MultiPolygon (with a hole) |  | `MultiPolygon.build([[[40, 40, 20, 45, 45, 30, 40, 40]], [[20, 35, 10, 30, 10, 10, 30, 5, 45, 20, 20, 35], [30, 20, 20, 15, 20, 25, 30, 20]]])`

GeometryCollection |  | `GeometryCollection([Point.build([30.0, 10.0]), LineString.build([10, 10, 20, 20, 10, 40]), Polygon.build([[40, 40, 20, 45, 45, 30, 40, 40]])])`



Geospatial feature and feature collections can be instantiated easily too:



```dart

  // A geospatial feature collection (with two features):

  FeatureCollection([

    Feature(

      id: 'ROG',

      // a point geometry with a position (lon, lat, elev)

      geometry: Point.build([-0.0014, 51.4778, 45.0]),

      properties: {

        'title': 'Royal Observatory',

        'city': 'London',

        'isMuseum': true,

      },

    ),

    Feature(

      id: 'TB',

      // a point geometry with a position (lon, lat)

      geometry: Point.build([-0.075406, 51.5055]),

      properties: {

        'title': 'Tower Bridge',

        'built': 1886,

      },

    ),

  ]);

```



### GeoJSON, WKT and WKB with geobase



More details in the article (2024-04-14) [Decode and encode GeoJSON, WKT and WKB in Dart and Flutter apps](https://medium.com/@navibyte/decode-and-encode-geojson-wkt-and-wkb-in-dart-and-flutter-apps-ab2ef4ece2f1).



GeoJSON, WKT and WKB formats are supported as input and output:



```dart

  // Parse a geometry from GeoJSON text.

  final geometry = LineString.parse(

    '{"type": "LineString", "coordinates": [[30,10],[10,30],[40,40]]}',

    format: GeoJSON.geometry,

  );



  // Encode a geometry as GeoJSON text.

  print(geometry.toText(format: GeoJSON.geometry));



  // Encode a geometry as WKT text.

  print(geometry.toText(format: WKT.geometry));



  // Encode a geometry as WKB bytes.

  final bytes = geometry.toBytes(format: WKB.geometry);



  // Decode a geometry from WKB bytes.

  LineString.decode(bytes, format: WKB.geometry);

```



A sample showing more deeply how to handle WKB and EWKB binary data:



```dart

  // to get a sample point, first parse a 3D point from WKT encoded string

  final p = Point.parse('POINT Z(-0.0014 51.4778 45)', format: WKT.geometry);



  // to encode a geometry as WKB/EWKB use toBytes() or toBytesHex() methods



  // encode as standard WKB data (format: `WKB.geometry`), prints:

  // 01e9030000c7bab88d06f056bfb003e78c28bd49400000000000804640

  final wkbHex = p.toBytesHex(format: WKB.geometry);

  print(wkbHex);



  // encode as Extended WKB data (format: `WKB.geometryExtended`), prints:

  // 0101000080c7bab88d06f056bfb003e78c28bd49400000000000804640

  final ewkbHex = p.toBytesHex(format: WKB.geometryExtended);

  print(ewkbHex);



  // otherwise encoded data equals, but bytes for the geometry type varies



  // there are some helper methods to analyse WKB/EWKB bytes or hex strings

  // (decodeFlavor, decodeEndian, decodeSRID and versions with hex postfix)



  // prints: "WkbFlavor.standard - WkbFlavor.extended"

  print('${WKB.decodeFlavorHex(wkbHex)} - ${WKB.decodeFlavorHex(ewkbHex)}');



  // when decoding WKB or EWKB data, a variant is detected automatically, so

  // both `WKB.geometry` and `WKB.geometryExtended` can be used

  final pointFromWkb = Point.decodeHex(wkbHex, format: WKB.geometry);

  final pointFromEwkb = Point.decodeHex(ewkbHex, format: WKB.geometry);

  print(pointFromWkb.equals3D(pointFromEwkb)); // prints "true"



  // SRID can be encoded only on EWKB data, this sample prints:

  // 01010000a0e6100000c7bab88d06f056bfb003e78c28bd49400000000000804640

  final ewkbHexWithSRID =

      p.toBytesHex(format: WKB.geometryExtended, crs: CoordRefSys.EPSG_4326);

  print(ewkbHexWithSRID);



  // if you have WKB or EWKB data, but not sure which, then you can fist check

  // a flavor and whether it contains SRID, prints: "SRID from EWKB data: 4326"

  if (WKB.decodeFlavorHex(ewkbHexWithSRID) == WkbFlavor.extended) {

    final srid = WKB.decodeSRIDHex(ewkbHexWithSRID);

    if (srid != null) {

      print('SRID from EWKB data: $srid');



      // after finding out CRS, an actual point can be decoded

      // Point.decodeHex(ewkbHexWithSRID, format: WKB.geometry);

    }

  }

```



Using Newline-delimited GeoJSON (or "GeoJSONL") is as easy as using the

standard GeoJSON:



```dart

  /// a feature collection encoded as GeoJSONL and containing two features that

  /// are delimited by the newline character \n

  const sample = '''

    {"type":"Feature","id":"ROG","geometry":{"type":"Point","coordinates":[-0.0014,51.4778,45]},"properties":{"title":"Royal Observatory","place":"Greenwich"}}

    {"type":"Feature","id":"TB","geometry":{"type":"Point","coordinates":[-0.075406,51.5055]},"properties":{"title":"Tower Bridge","built":1886}}

    ''';



  // parse a FeatureCollection object using the decoder for the GeoJSONL format

  final collection = FeatureCollection.parse(sample, format: GeoJSONL.feature);



  // ... use features read and returned in a feature collection object ...



  // encode back to GeoJSONL data

  print(collection.toText(format: GeoJSONL.feature, decimals: 5));

```



### Access GeoJSON resources with geodata



The [geodata](https://pub.dev/packages/geodata) package has the following

diagram describing a decision flowchart how to select a client class to access

GeoJSON features:






Quick start code to access a Web API service conforming to OGC API Features:



```dart

// 1. Get a client instance for a Web API endpoint.

final client = OGCAPIFeatures.http(endpoint: Uri.parse('...'));



// 2. Access/check metadata (meta, OpenAPI, conformance, collections) as needed.

final conformance = await client.conformance();

if (!conformance.conformsToFeaturesCore(geoJSON: true)) {

  return; // not conforming to core and GeoJSON - so return

}



// 3. Get a feature source for a specific collection.

final source = await client.collection('my_collection');



// 4. Access (and check) metadata for this collection.

final meta = await source.meta();

print('Collection title: ${meta.title}');



// 5. Access feature items.

final items = await source.itemsAll(limit: 100);



// 6. Check response metadata.

print('Timestamp: ${items.timeStamp}');



// 7. Get an iterable of feature objects.

final features = items.collection.features;



// 8. Loop through features (each with id, properties and geometry)

for (final feat in features) {

  print('Feature ${feat.id} with geometry: ${feat.geometry}');

}

```



## :rocket: Demos and samples



More guidance and code examples are provided on the

[geospatial.navibyte.dev](https://geospatial.navibyte.dev/) documentation site.



✨ See also the

[Geospatial demos for Dart](https://github.com/navibyte/geospatial_demos) code

repository for demo and sample apps demonstrating the usage of

[geobase](https://pub.dev/packages/geobase) and

[geodata](https://pub.dev/packages/geodata) packages along with other topics.



Code          | Description 

------------- | -----------

[earthquake_map](https://github.com/navibyte/geospatial_demos/tree/main/earthquake_map) | Shows earthquakes fetched from the [USGS web service](https://earthquake.usgs.gov/earthquakes/feed/) on a basic map view. The demo uses both [geobase](https://pub.dev/packages/geobase) and [geodata](https://pub.dev/packages/geodata) packages for geospatial data accesss. Discusses also state management based on [Riverpod](https://riverpod.dev/). The map UI is based on the [Google Maps Flutter](https://pub.dev/packages/google_maps_flutter) plugin.



## :newspaper_roll: News



2025-03-11

* ✨ The stable version 1.5.0 with [global grids](https://geospatial.navibyte.dev/v1/geobase/global-grids/), better WGS84 [projection](https://geospatial.navibyte.dev/v1/geobase/projections/) support and [unit conversions](https://geospatial.navibyte.dev/v1/geobase/unit-conversions/).

* All docs: [geospatial.navibyte.dev](https://geospatial.navibyte.dev/).

* Published packages at pub.dev:

  * [geobase version 1.5.0](https://pub.dev/packages/geobase/versions/1.5.0)



2024-11-10

* ✨ The stable release with [ellipsoidal geodesy functions](https://geospatial.navibyte.dev/v1/geobase/ellipsoidal-geodesy/) letting you calculate distances, bearings, destination positions and intermediate points along the Earth surface accurately.

* All docs: [geospatial.navibyte.dev](https://geospatial.navibyte.dev/).

* Published packages at pub.dev:

  * [geobase version 1.4.0](https://pub.dev/packages/geobase/versions/1.4.0+1)

  * [geodata version 1.3.0](https://pub.dev/packages/geodata/versions/1.3.0)



2024-07-26

* ✨ The [stable version 1.3.0](https://github.com/navibyte/geospatial/milestone/5) with centroid, polylabel, point-in-polygon and other cartesian 2D calculations enhanced - [read more](https://geospatial.navibyte.dev/v1/geobase/geometry-calculations/)!

* All docs: [geospatial.navibyte.dev](https://geospatial.navibyte.dev/).

* Published packages at pub.dev:

  * [geobase version 1.3.0](https://pub.dev/packages/geobase/versions/1.3.0)



2024-05-26

* ✨ The stable version 1.2.0 with the brand new documentation site published at [geospatial.navibyte.dev](https://geospatial.navibyte.dev/).

* Published packages at pub.dev:

  * [geobase version 1.2.0](https://pub.dev/packages/geobase/versions/1.2.0)

  * [geodata version 1.2.1](https://pub.dev/packages/geodata/versions/1.2.1)



2024-04-22

* ✨ The [stable version 1.1.0](https://github.com/navibyte/geospatial/milestone/1) adds support for Newline-delimited GeoJSON, EWKT and EWKB.

* See also the article [Decode and encode GeoJSON, WKT and WKB in Dart and Flutter apps](https://medium.com/@navibyte/decode-and-encode-geojson-wkt-and-wkb-in-dart-and-flutter-apps-ab2ef4ece2f1).

* Published packages at pub.dev:

  * [geobase version 1.1.0](https://pub.dev/packages/geobase/versions/1.1.0)

  * [geodata version 1.1.0](https://pub.dev/packages/geodata/versions/1.1.0)



2023-10-29

* ✨ The stable version 1.0.0 is now ready. See also the article [Geospatial tools for Dart - version 1.0 published](https://medium.com/@navibyte/geospatial-tools-for-dart-version-1-0-published-0f9673e510b3) at Medium

* [geobase version 1.0.0](https://github.com/navibyte/geospatial/issues/175)

* [geodata version 1.0.0](https://github.com/navibyte/geospatial/issues/187)



See also older news in the [changelog](CHANGELOG.md) of this repository.



## :building_construction: Roadmap



🗺️ [Roadmap 2025: The current state and candidate issues for the geobase package](https://github.com/navibyte/geospatial/issues/254).



🧩 See [open issues](https://github.com/navibyte/geospatial/issues) for planned features, requests for change, and observed bugs.



💡 Any comments, questions, suggestions of new features and other other contributions are welcome, of course!



📚 Documentation: [geospatial.navibyte.dev](https://geospatial.navibyte.dev/)



🪄 Active packages in this repository: 

* [geobase](https://pub.dev/packages/geobase) 

* [geodata](https://pub.dev/packages/geodata) 



⚠️ Not active packages in this repository:

* [geocore](https://pub.dev/packages/geocore)



## :house_with_garden: Authors



This project is authored by [Navibyte](https://navibyte.com).



## :copyright: License



### The project



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



Please see the [LICENSE](LICENSE).



### Included derivative work



This project contains portions of derivative work: 



* [geobase](dart/geobase): details about [DERIVATIVE](dart/geobase/DERIVATIVE.md) work.



Source repositories used when porting functionality to Dart and this project:

* [geodesy](https://github.com/chrisveness/geodesy) by Chris Veness 2002-2024

* [polylabel](https://github.com/mapbox/polylabel) by Mapbox 2016-2024

* [tinyqueue](https://github.com/mourner/tinyqueue) by Vladimir Agafonkin 2017-2024



## :star: Links and other resources



Some external links and other resources.



### Geospatial data formats and APIs



Geospatial:

* [GeoJSON](https://geojson.org/) based on [RFC 7946](https://tools.ietf.org/html/rfc7946)

* [Newline-delimited GeoJSON](https://stevage.github.io/ndgeojson/) with variants specified elsewhere:

  * [GeoJSONL](https://www.interline.io/blog/geojsonl-extracts/)

  * [GeoJSON Text Sequences](https://datatracker.ietf.org/doc/html/rfc8142)

* [Simple Feature Access - Part 1: Common Architecture](https://www.ogc.org/standards/sfa)

* [WKT](https://en.wikipedia.org/wiki/Well-known_text_representation_of_geometry) (Well-known text representation of geometry)  

* [WKB](https://en.wikipedia.org/wiki/Well-known_text_representation_of_geometry#Well-known_binary) (Well-known binary)

* [Coordinate Reference Systems](https://www.w3.org/2015/spatial/wiki/Coordinate_Reference_Systems) by W3C

* [EPSG](https://epsg.org/home.html) (Geodetic Parameter Dataset)

* [World Geodetic System](https://en.wikipedia.org/wiki/World_Geodetic_System), see also [EPSG:4326](https://epsg.io/4326) about WGS 84

* [Web Mercator projection](https://en.wikipedia.org/wiki/Web_Mercator_projection), see also [EPSG:3857](https://epsg.io/3857) and [Bing Maps Tile System](https://docs.microsoft.com/en-us/bingmaps/articles/bing-maps-tile-system)

* [Geographic coordinate conversion](https://en.wikipedia.org/wiki/Geographic_coordinate_conversion)

* [Geodetic datum](https://en.wikipedia.org/wiki/Geodetic_datum)

* [Ellipsoid](https://en.wikipedia.org/wiki/Ellipsoid)

* [Geodesic](https://en.wikipedia.org/wiki/Geodesic)

* [Geodesic on ellipsoid](https://en.wikipedia.org/wiki/Geodesics_on_an_ellipsoid)

* [Helmert transformation](en.wikipedia.org/wiki/Helmert_transformation)

* [ECEF](https://en.wikipedia.org/wiki/Earth-centered,_Earth-fixed_coordinate_system) (Earth-centered, Earth-fixed coordinate system)

* [UTM](https://en.wikipedia.org/wiki/Universal_Transverse_Mercator_coordinate_system) (Universal Transverse Mercator)

* [MGRS](https://en.wikipedia.org/wiki/Military_Grid_Reference_System) (Military Grid Reference System)

* [ISO 6709](https://en.wikipedia.org/wiki/ISO_6709) on standard representation of geographic point location by coordinates



OGC (The Open Geospatial Consortium) related:

* [OGC APIs](https://ogcapi.ogc.org/)

  * [OGC API Common](https://ogcapi.ogc.org/common/)

  * [OGC API Features](https://ogcapi.ogc.org/features/)

  * [OGC API Features - demo services](https://github.com/opengeospatial/ogcapi-features/tree/master/implementations)

  * [OGC API Features - github resources](https://github.com/opengeospatial/ogcapi-features)

  * [OGC API Features - schemas](http://schemas.opengis.net/ogcapi/features/)

* [OGC Web API Guidelines](https://github.com/opengeospatial/OGC-Web-API-Guidelines)

* [Simple Feature Access - Part 1: Common Architecture](https://www.ogc.org/standards/sfa)

* [OGC Two Dimensional Tile Matrix Set](https://docs.opengeospatial.org/is/17-083r2/17-083r2.html)



W3C

* [Spatial Data on the Web Best Practices](https://www.w3.org/TR/sdw-bp/)

  * [Spatial Things, Features and Geometry](https://www.w3.org/TR/sdw-bp/#spatial-things-features-and-geometry)



The OpenAPI Initiative (OAI) 

* [OpenAPI home](https://www.openapis.org/)

* [OpenAPI specification - latest](https://spec.openapis.org/oas/latest.html)



### Dart and Flutter programming



SDKs:

* [Dart](https://dart.dev/)

* [Flutter](https://flutter.dev/) 



Latest on Dart SDKs

* [Dart 3.7](https://medium.com/dartlang/announcing-dart-3-7-bf864a1b195c) with developer productivity enhancements.

* [Dart 3.6](https://medium.com/dartlang/announcing-dart-3-6-778dd7a80983) with digit separators and new features in the pub ecosystem (pub download counts and pub workspaces)

* [Dart 3.5](https://medium.com/dartlang/dart-3-5-6ca36259fa2f) with improvements in interoperability and an update on the Dart roadmap.

* [Dart 3.4](https://medium.com/dartlang/dart-3-4-bd8d23b4462a) with WebAssembly (WASM) updates and the roadmap for Dart *macros*. 

* [Dart 3.3](https://medium.com/dartlang/dart-3-3-325bf2bf6c13) with extension types,  evolving JavaScript-interoperability and experimental support for WebAssembly.

* [Dart 3.2](https://medium.com/dartlang/dart-3-2-c8de8fe1b91f) with improved language & developer experience.

* [Dart 3](https://medium.com/dartlang/announcing-dart-3-53f065a10635) with 100% sound null safety, new features (records, patterns, and class modifiers), and a peek into the future.

* [Dart 3 alpha](https://medium.com/dartlang/dart-3-alpha-f1458fb9d232) with records, patterns, access controls, portability advancements and the new Dart 3 type system (100% sound null safety)

* [Dart 2.18](https://medium.com/dartlang/dart-2-18-f4b3101f146c) with Objective-C & Swift interop, and improved type inference

* [Dart 2.17](https://medium.com/dartlang/dart-2-17-b216bfc80c5d) with enum member support, parameter forwarding to super classes, flexibility for named parameters, and more

* [Dart 2.16](https://medium.com/dartlang/dart-2-16-improved-tooling-and-platform-handling-dd87abd6bad1) with improved tooling and platform handling

* [Dart 2.15](https://medium.com/dartlang/dart-2-15-7e7a598e508a) with fast concurrency, constructor tear-offs, improved enums, and more

* [Dart 2.14](https://medium.com/dartlang/announcing-dart-2-14-b48b9bb2fb67) with Apple Silicon support, default lints etc.

* [Dart 2.13](https://medium.com/dartlang/announcing-dart-2-13-c6d547b57067) with new type aliases and more

* [Dart 2.12](https://medium.com/dartlang/announcing-dart-2-12-499a6e689c87) with sound null safety



Latest on Flutter SDKs

* [Flutter 3.29](https://medium.com/flutter/whats-new-in-flutter-3-29-f90c380c2317) running on Dart 3.7 and with updates to Impeller, Cupertino and DevTools.

* [Flutter 3.27](https://medium.com/flutter/whats-new-in-flutter-3-27-28341129570c) running on Dart 3.6 and with enhanced Impeller and improvements to Cupertino widgets.

* [Flutter 3.24](https://medium.com/flutter/whats-new-in-flutter-3-24-6c040f87d1e4) running on Dart 3.5 and with Multi-View Embedding and preview on Flutter GPU. 

* [Flutter 3.22](https://medium.com/flutter/whats-new-in-flutter-3-22-fbde6c164fe3) running on Dart 3.4 and stable support for WebAssembly (WASM), Graphics rendering enhancements, and AI updates.

* [Flutter 3.19](https://medium.com/flutter/whats-new-in-flutter-3-19-58b1aae242d2) running on Dart 3.3 and Gemini API integration, Impeller updates, and Windows Arm64 support.

* [Flutter 3.16](https://medium.com/flutter/whats-new-in-flutter-3-16-dba6cb1015d1) running on Dart 3.2 and with Material 3 by default, Impeller preview for Android, etc.

* [Flutter 3.13](https://medium.com/flutter/whats-new-in-flutter-3-13-479d9b11df4d) running on Dart 3.1 and with new 2D scrolling widgets and faster graphics.

* [Flutter 3.10](https://medium.com/flutter/whats-new-in-flutter-3-10-b21db2c38c73) running on Dart 3 and with seamless web and mobile integration, and stable Impleller for iOS.

* [Flutter 3.7](https://medium.com/flutter/whats-new-in-flutter-3-7-38cbea71133c) with Material 3 updates and iOS improvements

* [Flutter 3.3](https://medium.com/flutter/announcing-flutter-3-3-at-flutter-vikings-6f213e068793)

  * [What’s New in Flutter 3.3](https://medium.com/flutter/whats-new-in-flutter-3-3-893c7b9af1ff)

* [Flutter 3](https://medium.com/flutter/introducing-flutter-3-5eb69151622f)



Packages

* [pub.dev](https://pub.dev/)



Dart 3 migration

* [Dart 3 migration guide](https://dart.dev/resources/dart-3-migration)



Null-safety (Dart 2):

* Dart [null-safety](https://dart.dev/null-safety)

* The official [null-safety migration guide](https://dart.dev/null-safety/migration-guide)

* [Preparing the Dart and Flutter ecosystem for null safety](https://medium.com/dartlang/preparing-the-dart-and-flutter-ecosystem-for-null-safety-e550ce72c010)



Guidelines

* [Effective Dart](https://dart.dev/guides/language/effective-dart)



Roadmaps

* [Flutter roadmap](https://github.com/flutter/flutter/wiki/Roadmap)

* [The road to Dart 3: A fully sound, null safe language](https://medium.com/dartlang/the-road-to-dart-3-afdd580fbefa)

* [Dart language evolution](https://dart.dev/guides/language/evolution)

* [Dart SDK milestones](https://github.com/dart-lang/sdk/milestones)

* Waiting for [new features](https://github.com/dart-lang/language/projects/1) on the Dart [language](https://github.com/dart-lang/language) too ...

  * [Patterns and related features #546](https://github.com/dart-lang/language/issues/546)

  * [Type capability modifiers #2242](https://github.com/dart-lang/language/issues/2242)

  * [Inline classes #2727](https://github.com/dart-lang/language/issues/2727)

  * [Static metaprogramming #1482](https://github.com/dart-lang/language/issues/1482) with data classes



### Dart and Flutter libraries



There are thousands of excellent libraries available at 

[pub.dev](https://pub.dev/).



Here listed only those that are used (depended directly) by code packages of

this repository (on the latest release):



Package @ pub.dev | Code @ GitHub | Description

----------------- | ------------- | -----------

[http](https://pub.dev/packages/http) | [dart-lang/http](https://github.com/dart-lang/http) | A composable API for making HTTP requests in Dart.

[meta](https://pub.dev/packages/meta) | [dart-lang/sdk](https://github.com/dart-lang/sdk/tree/master/pkg/meta) | This package defines annotations that can be used by the tools that are shipped with the Dart SDK.

[proj4dart](https://pub.dev/packages/proj4dart) | [maRci002/proj4dart](https://github.com/maRci002/proj4dart) | Proj4dart is a Dart library to transform point coordinates from one coordinate system to another, including datum transformations (Dart version of proj4js/proj4js).

[very_good_analysis](https://pub.dev/packages/very_good_analysis) | [VeryGoodOpenSource/very_good_analysis](https://github.com/VeryGoodOpenSource/very_good_analysis) | Lint rules for Dart and Flutter.



In some previous releases also following are utilized:



Package @ pub.dev | Code @ GitHub | Description

----------------- | ------------- | -----------

[collection](https://pub.dev/packages/collection) | [dart-lang/collection](https://github.com/dart-lang/collection) | Collections and utilities functions and classes related to collections. 

[equatable](https://pub.dev/packages/equatable) | [felangel/equatable](https://github.com/felangel/equatable) | Simplify Equality Comparisons | A Dart abstract class that helps to implement equality without needing to explicitly override == and hashCode.

[synchronized](https://pub.dev/packages/synchronized) | [tekartik/synchronized.dart](https://github.com/tekartik/synchronized.dart/tree/master/synchronized) | Basic lock mechanism to prevent concurrent access to asynchronous code.