Ecosyste.ms: Awesome
An open API service indexing awesome lists of open source software.
https://github.com/bahung1221/dart-vector-tile
A simple Dart package to encode & decode Mapbox Vector Tile
https://github.com/bahung1221/dart-vector-tile
dart-vector-tile geojson-format vector-tile vector-tile-parser vector-tile-to-geojson
Last synced: about 1 month ago
JSON representation
A simple Dart package to encode & decode Mapbox Vector Tile
- Host: GitHub
- URL: https://github.com/bahung1221/dart-vector-tile
- Owner: bahung1221
- License: mit
- Created: 2021-02-08T19:49:16.000Z (over 3 years ago)
- Default Branch: master
- Last Pushed: 2023-12-02T05:12:00.000Z (7 months ago)
- Last Synced: 2024-05-08T20:02:42.353Z (about 2 months ago)
- Topics: dart-vector-tile, geojson-format, vector-tile, vector-tile-parser, vector-tile-to-geojson
- Language: Dart
- Homepage: https://pub.dev/packages/vector_tile
- Size: 287 KB
- Stars: 13
- Watchers: 5
- Forks: 10
- Open Issues: 3
-
Metadata Files:
- Readme: README.md
- Changelog: CHANGELOG.md
- License: LICENSE
Lists
- awesome-vector-tiles - dart-vector-tile - A simple Dart package to encode & decode Mapbox Vector Tile. (Uncategorized / Uncategorized)
README
## Dart Vector Tile
Package to `encode & decode` vector tiles. A implementation of [Mapbox Vector Tile specification 2.1](https://github.com/mapbox/vector-tile-spec).
Features:
- [x] Parse `.mvt`/`.pbf` file to raw vector tile format.
- [x] Decode raw vector tile feature to GeoJson format (only GeoJson Feature type).
- [x] Decode raw vector tile to GeoJson FeatureCollection format.
- [x] Encode & create vector tile file from raw format data.
- [ ] Encode & create vector tile file from GeoJson format data. (TODO)
### Parse & Decode
Parse and then decode each feature to GeoJson from a vector tile file,
either `.pbf` or `.mvt` should work:
```dart
import 'vector_tile/vector_tile.dart';
main() async {
final tileData = await File('../data/sample-12-3262-1923.pbf').readAsBytes();
final tile = await VectorTile.fromBytes(bytes: tileData);
final layer = tile.layers.firstWhere((layer) => layer.name == 'transportation');
layer.features.forEach((feature) {
// Geometry will be decode on-demand to avoid redundant calculating
feature.decodeGeometry();
// Each GeometryType will have different geometry data format
// So we must explicit check GeometryType and specific generic type here
if (feature.geometryType == GeometryType.Point) {
var geojson = feature.toGeoJson(x: 3262, y: 1923, z: 12);
print(geojson?.properties);
print(geojson?.geometry?.coordinates);
}
})
}
```
We also can decode feature to GeoJson data first and explicit cast the type later, there are more examples code in [example folder](example/lib/main.dart).
[Sample VectorTile fields](#sample-vectortile-raw-decoded-as-json)
### Encode
Create VectorTile from raw data and then encode it into protobuf file:
```dart
import 'package:vector_tile/raw/raw_vector_tile.dart';
main() async {
var values = [
createVectorTileValue(intValue: Int64(65)),
createVectorTileValue(stringValue: 'basketball'),
];
var features = [
createVectorTileFeature(
id: Int64(31162829580),
tags: [0, 96, 1, 348],
type: VectorTile_GeomType.POINT,
geometry: [9, 8058, 1562],
),
];
var layers = [
createVectorTileLayer(
name: 'building',
extent: 4096,
version: 2,
keys: ['render_height', 'render_min_height'],
values: values,
features: features,
),
];
var tile = createVectorTile(layers: layers);
// Save to disk
await File('./gen/tile.pbf').writeAsBytes(tile.writeToBuffer());
}
```
### API
**Class VectorTile**:
- `T toGeoJson({int x, int y, int z})`: Convert `VectorTile` to a `GeoJson FeatureCollection`. each Feature inside will include **lon/lat** coordinates calculating and will have generic type of [GeoJson class](lib/util/geo_json.dart)
because each geometry type will have different coordinates format. So you must given an explicit GeoJson type or do a type cast here (See decode example above).
**Class VectorTileFeature**:
- `decodeGeometry()`: Decode geometry data from raw data, this data also will be used later when we call `getGeoJson` method.
- `T toGeoJson({int x, int y, int z})`: Convert `VectorTile Feature` to `GeoJson Feature` format include **lon/lat** coordinates calculating, this method will return generic type of [GeoJson class](lib/util/geo_json.dart)
because each geometry type will have different coordinates format. So you must given an explicit GeoJson type or do a type cast here (See decode example above).
### Sample VectorTile (raw) decoded (as JSON)
```json
{
"layers": [
{
"name": "poi",
"features": {
"id": 31162829580,
"tags": [
0,
0,
1,
1
],
"type": "POINT",
"geometry": [
9,
8058,
1562
]
},
"keys": [
"render_height",
"name"
],
"values": [
{
"intValue": 65
},
{
"stringValue": "basketball"
}
],
"extent": 4096,
"version": 2
}
]
}
```
### Sample VectorTileFeature as GeoJson decoded
```json
{
"type": "Feature",
"geometry": {"type": "Point", "coordinates": [102.0, 0.5]},
"properties": {
"render_height": {
"stringValue": null,
"floatValue": null,
"doubleValue": null,
"intValue": 65,
"uintValue": null,
"sintValue": null,
"boolValue": null
},
"name": {
"stringValue": "basketball",
"floatValue": null,
"doubleValue": null,
"intValue": null,
"uintValue": null,
"sintValue": null,
"boolValue": null
}
}
}
```