Download scripts

- downloading efele.net shapefile
- querying overpass api for boundaries

1 files changed, 80 insertions, 0 deletions

diff --git a/index.js b/index.js
new file mode 100644
index 0000000..6d6196e
--- /dev/null
+++ b/index.js
@@ -0,0 +1,80 @@
+var fs = require('fs'),
+  http = require('http')
+
+var async = require('async'),
+  overpass = require('query-overpass'),
+  shp = require('shpjs')
+
+
+var toArrayBuffer = function(buffer) {
+  var ab = new ArrayBuffer(buffer.length)
+  var view = new Uint8Array(ab)
+  for (var i = 0; i < buffer.length; ++i) {
+    view[i] = buffer[i]
+  }
+  return view
+}
+
+var extractToGeoJson = function(callback) {
+  shp(toArrayBuffer(fs.readFileSync('./downloads/tz_world_mp.zip')))
+    .then(function(geojson) { console.log('extract success'); callback(null, geojson) })
+    .catch(function(e){ console.log('extract err', e); callback(e) })
+}
+
+var osmBoundarySources = require('./osmBoundarySources.json')
+
+async.auto({
+  makeDownloadsDir: function(cb) {
+    console.log('creating downloads dir')
+    fs.mkdir('./downloads', function(err) {
+      if(err && err.code === 'EEXIST') {
+        cb()
+      } else {
+        cb(err)
+      }
+    })
+  },
+  getEfeleShapefile: ['makeDownloadsDir', function(results, cb) {
+    console.log('downloads efele.net shapefile')
+    return cb()
+    var file = fs.createWriteStream('./downloads/tz_world_mp.zip')
+    http.get('http://efele.net/maps/tz/world/tz_world_mp.zip', function(response) {
+      response.pipe(file)
+      file
+        .on('finish', function() {
+          file.close(cb)
+        })
+        .on('error', cb)
+    })
+  }],
+  extractShapefile: ['getEfeleShapefile', function(results, cb) {
+    console.log('extracting efele.net shapefile')
+    extractToGeoJson(cb)
+  }],
+  getOsmBoundaries: ['makeDownloadsDir', function(results, cb) {
+    console.log('downloading osm boundaries')
+    var boundaryIds = Object.keys(osmBoundarySources)
+    async.eachSeries(boundaryIds,
+      function(boundaryId, boundaryCallback) {
+        var cfg = osmBoundarySources[boundaryId]
+        console.log('osm boundary for:', boundaryId, cfg.query)
+        overpass(cfg.query, function(err, data) {
+          if(err) { return boundaryCallback(err) }
+          if(!data.features || data.features.length == 0) {
+            err = new Error('Invalid geojson for boundary: ' + boundaryId)
+            return boundaryCallback(err)
+          }
+          // union all multi-polygons / polygons into one
+          fs.writeFile('./downloads/' + boundaryId, JSON.stringify(data, null, 2), boundaryCallback)
+        }, { flatProperties: true })
+      }, cb)
+  }]
+}, function(err) {
+  console.log('done')
+  if(err) {
+    console.log('error!', err)
+    return
+  }
+
+  //console.log(osmBoundarySources)
+})
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