demarches-normaliennes/app/javascript/components/MapEditor/readGeoFile.js
2021-05-24 11:57:00 +02:00

88 lines
2.3 KiB
JavaScript

import { gpx, kml } from '@tmcw/togeojson/dist/togeojson.es.js';
import { generateId } from '../shared/mapbox/utils';
export function readGeoFile(file) {
const isGpxFile = file.name.includes('.gpx');
const reader = new FileReader();
return new Promise((resolve) => {
reader.onload = (event) => {
const xml = new DOMParser().parseFromString(
event.target.result,
'text/xml'
);
const featureCollection = normalizeFeatureCollection(
isGpxFile ? gpx(xml) : kml(xml),
file.name
);
resolve(featureCollection);
};
reader.readAsText(file, 'UTF-8');
});
}
function normalizeFeatureCollection(featureCollection, filename) {
const features = [];
for (const feature of featureCollection.features) {
switch (feature.geometry.type) {
case 'MultiPoint':
for (const coordinates of feature.geometry.coordinates) {
features.push({
type: 'Feature',
geometry: {
type: 'Point',
coordinates
},
properties: feature.properties
});
}
break;
case 'MultiLineString':
for (const coordinates of feature.geometry.coordinates) {
features.push({
type: 'Feature',
geometry: {
type: 'LineString',
coordinates
},
properties: feature.properties
});
}
break;
case 'MultiPolygon':
for (const coordinates of feature.geometry.coordinates) {
features.push({
type: 'Feature',
geometry: {
type: 'Polygon',
coordinates
},
properties: feature.properties
});
}
break;
case 'GeometryCollection':
for (const geometry of feature.geometry.geometries) {
features.push({
type: 'Feature',
geometry,
properties: feature.properties
});
}
break;
default:
features.push(feature);
}
}
featureCollection.filename = `${generateId()}-${filename}`;
featureCollection.features = features.map((feature) => ({
...feature,
properties: {
...feature.properties,
filename: featureCollection.filename
}
}));
return featureCollection;
}