1 files changed, 171 insertions, 0 deletions
diff --git a/bin/reduceDuplicates.js b/bin/reduceDuplicates.js
new file mode 100755
index 0000000..c9a7769
--- /dev/null
+++ b/bin/reduceDuplicates.js
@@ -0,0 +1,171 @@
+#!/usr/bin/env node
+
+/**
+ * Remove duplicates (exact tags) at the same location or within a small proximity.
+ */
+
+const fs = require('fs')
+const { Readable, Transform, pipeline } = require('stream')
+const ndjson = require('ndjson')
+const cluster = require('../lib/cluster.js')
+
+const argv = require('yargs/yargs')(process.argv.slice(2))
+  .option('debug', {
+    type: 'boolean',
+    description: 'Dumps full debug logs'
+  })
+  .argv
+
+if (argv._.length < 2) {
+  console.error("Usage: ./reduceDuplicates.js input.geojson output.geojson")
+  process.exit(1)
+}
+
+const inputFile = argv._[0]
+const outputFile = argv._[1]
+
+if (!fs.existsSync(inputFile)) {
+  console.error(`${inputFile} not found`)
+  process.exit(1)
+}
+
+let sourceCount = 0
+const features = {}
+
+const index = new Transform({
+  readableObjectMode: true,
+  writableObjectMode: true,
+  transform(feature, encoding, callback) {
+    sourceCount++
+
+    if (sourceCount % 10000 === 0) {
+      process.stdout.write(` ${sourceCount / 1000}k\r`)
+    }
+
+    const key = [
+      feature.properties['addr:unit'],
+      feature.properties['addr:housename'],
+      feature.properties['addr:housenumber'],
+      feature.properties['addr:street'],
+      feature.properties['addr:suburb'],
+      feature.properties['addr:state'],
+      feature.properties['addr:postcode']
+    ].join('/')
+
+    if (!(key in features)) {
+      features[key] = []
+    }
+    features[key].push(feature)
+
+    callback()
+  }
+})
+
+let reduceIndex = 0
+const reduce = new Transform({
+  readableObjectMode: true,
+  writableObjectMode: true,
+  transform(key, encoding, callback) {
+    reduceIndex++
+    if (reduceIndex % 10000 === 0) {
+      process.stdout.write(` ${reduceIndex / 1000}k / ${Math.round(sourceCount / 1000)}k (${Math.round(reduceIndex / sourceCount * 100)}%)\r`)
+    }
+
+    const groupedFeatures = features[key]
+    if (groupedFeatures.length === 1) {
+      // address not duplicated
+
+      this.push(groupedFeatures[0])
+    } else {
+      // address appears multiple times
+
+      const sameCoordinates = [...new Set(groupedFeatures.map(f => f.geometry.coordinates.join(',')))].length <= 1
+      if (sameCoordinates) {
+        // features have same properties and same geometry, so true duplicates can reduce to one
+        this.push(groupedFeatures[0])
+      } else {
+        // cluster features with a threshold of 25m
+        const clusters = cluster(groupedFeatures, 25)
+
+        // if clustered into a single cluster, then output a single average feature
+        if (clusters.length === 1) {
+          const averageCoordinates = [
+            groupedFeatures.map(f => f.geometry.coordinates[0]).reduce((acc, cur) => acc + cur) / groupedFeatures.length,
+            groupedFeatures.map(f => f.geometry.coordinates[1]).reduce((acc, cur) => acc + cur) / groupedFeatures.length
+          ]
+          const averageFeature = groupedFeatures[0]
+          averageFeature.geometry.coordinates = averageCoordinates
+
+          this.push(averageFeature)
+        } else {
+          // more than one cluster, reduce those clustered into one, and then report all the results
+          const clusterAverages = clusters.map(cluster => {
+            if (cluster.length === 1) {
+              return cluster
+            } else {
+              const averageCoordinates = [
+                cluster.map(f => f.geometry.coordinates[0]).reduce((acc, cur) => acc + cur) / groupedFeatures.length,
+                cluster.map(f => f.geometry.coordinates[1]).reduce((acc, cur) => acc + cur) / groupedFeatures.length
+              ]
+              const averageFeature = cluster[0]
+              averageFeature.geometry.coordinates = averageCoordinates
+              return averageFeature
+            }
+          })
+
+          // report these as address points with the same attributes but different locations beyond the threshold
+          if (debugDuplicateAddressStream) {
+            const webOfMatches = {
+              type: 'Feature',
+              properties: clusterAverages[0].properties,
+              geometry: {
+                type: 'LineString',
+                coordinates: averageClusters.map(p => p.geometry.coordinates)
+              }
+            }
+            debugDuplicateAddressStream.write(webOfMatches)
+          }
+        }
+      }
+    }
+
+    callback()
+  }
+})
+
+const debugDuplicateAddressesStream = argv.debug ?
+  ndjson.stringify()
+    .pipe(fs.createWriteStream('debug/reduceDuplicates/duplicateAddresses.geojson'))
+  : null
+
+// first pass to index by geometry
+console.log('First pass to index by address properties')
+pipeline(
+  fs.createReadStream(inputFile),
+  ndjson.parse(),
+  index,
+  err => {
+    if (err) {
+      console.log(err)
+      process.exit(1)
+    } else {
+      console.log(`  of ${sourceCount} features found ${Object.keys(features).length} unique addresses`)
+      // second pass to reduce overlapping features
+      pipeline(
+        Readable.from(Object.keys(features)),
+        reduce,
+        ndjson.stringify(),
+        fs.createWriteStream(outputFile),
+        err => {
+          if (err) {
+            console.log(err)
+            process.exit(1)
+          } else {
+            debugDuplicateAddressesStream.end()
+            process.exit(0)
+          }
+        }
+      )
+    }
+  }
+)