:compass: Geospatial tools for Dart

<a title="Stefan Kühn (Fotograf), CC BY-SA 3.0 <https://creativecommons.org/licenses/by-sa/3.0>, via Wikimedia Commons" href="https://commons.wikimedia.org/wiki/File:Azimutalprojektion-schief_kl-cropped.png"><img src="https://raw.githubusercontent.com/navibyte/geospatial_docs/v2023-08-12/assets/doc/projections/azimutal/Azimutalprojektion-schief_kl-cropped.png" align="right"></a>

Geospatial data structures, tools and utilities for Dart and Flutter - 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!

🗺️ Roadmap 2025: The current state and candidate issues for the geobase package.

✨ New (2025-03-11): The stable version 1.5.0 with global grids, better WGS84 projection support and unit conversions.

✨ New (2024-11-10): The stable release with ellipsoidal geodesy functions 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!

:package: Packages

Dart code packages published at pub.dev:

Code | Package | Description -------------- | --------| ----------- :globe_with_meridians: geobase | | Geospatial data structures (coordinates, geometries, features, metadata), ellipsoidal and spherical geodesy, projections and tiling schemes. Vector data format support for GeoJSON, WKT and WKB. :earth_americas: geodata | | Geospatial feature service Web APIs with support for GeoJSON and OGC API Features clients.

📚 Documentation

Comprehensive guidance on how to use package and about Geospatial tools for Dart is available on the geospatial.navibyte.dev website.

Overview topics about Geospatial tools for Dart:

The geobase package documentation by chapters:

The geodata package documentation by chapters:

:sparkles: Features

Key features of the 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, MGRS and ECEF (earth-centric earth-fixed) support
📅 temporal data structures (instant, interval) and spatial extents
📃 vector data formats supported (GeoJSON, Newline-delimited GeoJSON, WKT, WKB )
🗺️ coordinate projections (built-in WGS84 based projections on geographic, geocentric, UTM and Web Mercator coordinates + external 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 package:

🪄 Client-side data source abstraction for geospatial feature service Web APIs.
🌐 The GeoJSON client to read features from static web resources and local files, supports also Newline-delimited GeoJSON data.
🌎 The OGC API 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 | Supported for accessing metadata and GeoJSON feature collections. OGC API - Features - Part 2: Coordinate Reference Systems by Reference | Supported. OGC API - Features - Part 3: Filtering<br/>Common Query Language (CQL2) | Partially supported (conformance classes, queryables, features filter).

:keyboard: Sample code

Geodesy functions with geobase

Ellipsoidal and spherical geodesy functions to calculate distances etc.:

  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

Geospatial

Install / Use

README