This script pulls all visible layers from Get Food NYC and converts them to geojson.
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Last active
April 13, 2020 19:51
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Get data from Get Food NYC http://morr.maps.arcgis.com/apps/webappviewer/index.html?id=27fd1b2d94234c0ea45e928215d306cd
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| import proj4 from 'proj4' | |
| import { promises as fs } from 'fs' | |
| import fetch from 'node-fetch' | |
| proj4.defs('EPSG:4326', '+title=WGS 84 (long/lat) +proj=longlat +ellps=WGS84 +datum=WGS84 +units=degrees'); | |
| proj4.defs('EPSG:3857','+proj=merc +a=6378137 +b=6378137 +lat_ts=0.0 +lon_0=0.0 +x_0=0.0 +y_0=0 +k=1.0 +units=m +nadgrids=@null +wktext +no_defs') | |
| function convertToWGS84(coords) { | |
| return proj4('EPSG:3857', 'EPSG:4326', coords) | |
| } | |
| async function main() { | |
| const webmapId = 'd171a1413c7f44e0aeef34de37355d4c' | |
| //pull all layers for web map | |
| const layers = await fetch(`https://www.arcgis.com/sharing/rest/content/items/${webmapId}/data?f=json`) | |
| .then(res => res.json()) | |
| .then(async ({ operationalLayers }) => { | |
| //filter for only visible layers | |
| const visibleLayers = operationalLayers.filter(layer => layer.visibility && layer.itemId) | |
| //pull all data for each layer | |
| return Promise.all(visibleLayers.map(async ({ title, itemId }) => { | |
| const features = await fetch(`http://maps.arcgis.com/sharing/rest/content/items/${itemId}/data?f=json`) | |
| .then(res => res.json()) | |
| .then(data => { | |
| //append all features in layers to a single feature collection | |
| return data.layers.reduce((collection, layer) => { | |
| //assumes esriGeometryPoint and EPSG:3857 | |
| const features = layer.featureSet.features.map(feature => ({ | |
| type: "Feature", | |
| properties: feature.attributes, | |
| geometry: { | |
| type: "Point", | |
| coordinates: convertToWGS84([feature.geometry.x, feature.geometry.y]) | |
| } | |
| })) | |
| return [...collection, ...features] | |
| }, []) | |
| }).catch(error => error.message) | |
| return { | |
| title, | |
| itemId, | |
| features | |
| } | |
| })) | |
| }) | |
| layers.forEach(({ title, itemId, features }) => { | |
| //write each layer to file | |
| fs.writeFile(`./layers/${itemId}.geojson`, JSON.stringify({ | |
| type: "FeatureCollection", | |
| name: title, | |
| features, | |
| })); | |
| }) | |
| } | |
| main() |
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| { | |
| "name": "nyc-food-map", | |
| "version": "1.0.0", | |
| "description": "", | |
| "main": "index.js", | |
| "scripts": { | |
| "test": "echo \"Error: no test specified\" && exit 1", | |
| "start": "node -r esm index.js" | |
| }, | |
| "keywords": [], | |
| "author": "", | |
| "license": "ISC", | |
| "dependencies": { | |
| "esm": "^3.2.25", | |
| "node-fetch": "^2.6.0", | |
| "proj4": "^2.6.1" | |
| } | |
| } |
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