mirecnet-false-fords-cleanup

index.js

/*
Overpass QL for the input file (mirecnet-false-fords.osm):

```
[out:xml][timeout:600][bbox:{{bbox}}];
(
way[highway]->.w1;
way[waterway]->.w2;
node[!"ford"](w.w1)(w.w2)(user:"Mirecnet");
);
out meta;
```
*/

const fs = require("fs");
const xml2js = require("xml2js");

let data;

xml2js.parseString(
  fs.readFileSync("mirecnet-false-fords.osm"),
  (err, result) => {
    data = result;
  }
);

const candidateNodes = new Map();

for (const node of data.osm.node) {
  // only nodes with tags
  if (!node.tag && node.$.user === "Mirecnet") {
    candidateNodes.set(node.$.id, node);
  }
}

const nodeInWaterwayRefs = new Map();

const nodeInHighwayRefs = new Map();

const ignoreRefs = new Set(); // skip nodes of multiple highways or waterways

for (const way of data.osm.way) {
  const tags = tagsToMap(way);

  for (const ref1 of ensureArray(way.nd)) {
    const ref = ref1.$.ref;

    if (!candidateNodes.has(ref)) {
      continue;
    }

    if (tags.highway) {
      if (nodeInHighwayRefs.has(ref)) {
        ignoreRefs.add(ref);
      }

      nodeInHighwayRefs.set(ref, way);
    }

    if (tags.waterway) {
      if (nodeInWaterwayRefs.has(ref)) {
        ignoreRefs.add(ref);
      }

      nodeInWaterwayRefs.set(ref, way);
    }
  }
}

let nextRef = 0;

for (const [nr, waterway] of nodeInWaterwayRefs.entries()) {
  if (ignoreRefs.has(nr)) {
    continue;
  }

  const highway = nodeInHighwayRefs.get(nr);

  if (!highway) {
    continue;
  }

  for (let i = 0; i < waterway.nd.length; i++) {
    const ref = waterway.nd[i].$.ref;

    if (ref !== nr) {
      continue;
    }

    waterway.$.action = "modify";

    nextRef--;

    waterway.nd[i].$.ref = nextRef;

    const newNode = structuredClone(candidateNodes.get(nr));

    newNode.$.id = nextRef;

    delete newNode.$.timestamp;
    delete newNode.$.uid;
    delete newNode.$.user;
    delete newNode.$.changeset;

    newNode.$.lat = Number(newNode.$.lat) + 0.000001;
    newNode.$.lon = Number(newNode.$.lon) + 0.0000015;

    data.osm.node.push(newNode);

    break;
  }
}

const builder = new xml2js.Builder();

console.log(builder.buildObject(data));

function tagsToMap(a) {
  const tags = {};

  for (const tag of ensureArray(a.tag)) {
    tags[tag.$.k] = tag.$.v;
  }

  return tags;
}

function ensureArray(a) {
  return !a ? [] : Array.isArray(a) ? a : [a];
}