Files
openlayers/examples/geojson-vt.js
2018-01-11 13:33:41 -07:00

101 lines
2.4 KiB
JavaScript

// NOCOMPILE
import Map from '../src/ol/Map.js';
import View from '../src/ol/View.js';
import GeoJSON from '../src/ol/format/GeoJSON.js';
import OSM from '../src/ol/source/OSM.js';
import VectorTileSource from '../src/ol/source/VectorTile.js';
import TileLayer from '../src/ol/layer/Tile.js';
import VectorTileLayer from '../src/ol/layer/VectorTile.js';
import Projection from '../src/ol/proj/Projection.js';
var replacer = function(key, value) {
if (value.geometry) {
var type;
var rawType = value.type;
var geometry = value.geometry;
if (rawType === 1) {
type = 'MultiPoint';
if (geometry.length == 1) {
type = 'Point';
geometry = geometry[0];
}
} else if (rawType === 2) {
type = 'MultiLineString';
if (geometry.length == 1) {
type = 'LineString';
geometry = geometry[0];
}
} else if (rawType === 3) {
type = 'Polygon';
if (geometry.length > 1) {
type = 'MultiPolygon';
geometry = [geometry];
}
}
return {
'type': 'Feature',
'geometry': {
'type': type,
'coordinates': geometry
},
'properties': value.tags
};
} else {
return value;
}
};
var tilePixels = new Projection({
code: 'TILE_PIXELS',
units: 'tile-pixels'
});
var map = new Map({
layers: [
new TileLayer({
source: new OSM()
})
],
target: 'map',
view: new View({
center: [0, 0],
zoom: 2
})
});
var url = 'data/geojson/countries.geojson';
fetch(url).then(function(response) {
return response.json();
}).then(function(json) {
var tileIndex = geojsonvt(json, {
extent: 4096,
debug: 1
});
var vectorSource = new VectorTileSource({
format: new GeoJSON(),
tileLoadFunction: function(tile) {
var format = tile.getFormat();
var tileCoord = tile.getTileCoord();
var data = tileIndex.getTile(tileCoord[0], tileCoord[1], -tileCoord[2] - 1);
var features = format.readFeatures(
JSON.stringify({
type: 'FeatureCollection',
features: data ? data.features : []
}, replacer));
tile.setLoader(function() {
tile.setFeatures(features);
tile.setProjection(tilePixels);
});
},
url: 'data:' // arbitrary url, we don't use it in the tileLoadFunction
});
var vectorLayer = new VectorTileLayer({
source: vectorSource
});
map.addLayer(vectorLayer);
});