Spaces:
Sleeping
Sleeping
File size: 2,717 Bytes
cd6720a | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 | # vector-tile
This library reads [Mapbox Vector Tiles](https://github.com/mapbox/vector-tile-spec) and allows access to the layers and features.
## Example
```js
import {VectorTile} from '@mapbox/vector-tile';
import Protobuf from 'pbf';
const tile = new VectorTile(new Protobuf(data));
// Contains a map of all layers
tile.layers;
const landuse = tile.layers.landuse;
// Amount of features in this layer
landuse.length;
// Returns the first feature
landuse.feature(0);
```
Vector tiles contained in [serialtiles-spec](https://github.com/mapbox/serialtiles-spec)
are gzip-encoded, so a complete example of parsing them with the native
zlib module would be:
```js
import {VectorTile} from '@mapbox/vector-tile';
import Protobuf from 'pbf';
import {gunzipSync} from 'zlib';
const buffer = gunzipSync(data);
const tile = new VectorTile(new Protobuf(buffer));
```
## Install
To install:
npm install @mapbox/vector-tile
## API Reference
### VectorTile
An object that parses vector tile data and makes it readable.
#### Constructor
- **new VectorTile(protobuf[, end])** —
parses the vector tile data contained in the given [Protobuf](https://github.com/mapbox/pbf) object,
saving resulting layers in the created object as a `layers` property. Optionally accepts end index.
#### Properties
- **layers** (Object) — an object containing parsed layers in the form of `{<name>: <layer>, ...}`,
where each layer is a `VectorTileLayer` object.
### VectorTileLayer
An object that contains the data for a single vector tile layer.
#### Properties
- **version** (`Number`, default: `1`)
- **name** (`String`) — layer name
- **extent** (`Number`, default: `4096`) — tile extent size
- **length** (`Number`) — number of features in the layer
#### Methods
- **feature(i)** — get a feature (`VectorTileFeature`) by the given index from the layer.
### VectorTileFeature
An object that contains the data for a single feature.
#### Properties
- **type** (`Number`) — type of the feature (also see `VectorTileFeature.types`)
- **extent** (`Number`) — feature extent size
- **id** (`Number`) — feature identifier, if present
- **properties** (`Object`) — object literal with feature properties
#### Methods
- **loadGeometry()** — parses feature geometry and returns an array of
[Point](https://github.com/mapbox/point-geometry) arrays (with each point having `x` and `y` properties)
- **bbox()** — calculates and returns the bounding box of the feature in the form `[x1, y1, x2, y2]`
- **toGeoJSON(x, y, z)** — returns a GeoJSON representation of the feature. (`x`, `y`, and `z` refer to the containing tile's index.)
|