mapcomplete/Logic/Osm/Actions/SplitAction.ts
2022-01-26 21:40:38 +01:00

285 lines
11 KiB
TypeScript

import {OsmObject, OsmWay} from "../OsmObject";
import {Changes} from "../Changes";
import {GeoOperations} from "../../GeoOperations";
import OsmChangeAction from "./OsmChangeAction";
import {ChangeDescription} from "./ChangeDescription";
import RelationSplitHandler from "./RelationSplitHandler";
interface SplitInfo {
originalIndex?: number, // or negative for new elements
lngLat: [number, number],
doSplit: boolean
}
export default class SplitAction extends OsmChangeAction {
private readonly wayId: string;
private readonly _splitPointsCoordinates: [number, number] []// lon, lat
private _meta: { theme: string, changeType: "split" };
private _toleranceInMeters: number;
/**
* Create a changedescription for splitting a point.
* Will attempt to reuse existing points
* @param wayId
* @param splitPointCoordinates: lon, lat
* @param meta
* @param toleranceInMeters: if a splitpoint closer then this amount of meters to an existing point, the existing point will be used to split the line instead of a new point
*/
constructor(wayId: string, splitPointCoordinates: [number, number][], meta: { theme: string }, toleranceInMeters = 5) {
super(wayId, true)
this.wayId = wayId;
this._splitPointsCoordinates = splitPointCoordinates
this._toleranceInMeters = toleranceInMeters;
this._meta = {...meta, changeType: "split"};
}
private static SegmentSplitInfo(splitInfo: SplitInfo[]): SplitInfo[][] {
const wayParts = []
let currentPart = []
for (const splitInfoElement of splitInfo) {
currentPart.push(splitInfoElement)
if (splitInfoElement.doSplit) {
// We have to do a split!
// We add the current index to the currentParts, flush it and add it again
wayParts.push(currentPart)
currentPart = [splitInfoElement]
}
}
wayParts.push(currentPart)
return wayParts.filter(wp => wp.length > 0)
}
async CreateChangeDescriptions(changes: Changes): Promise<ChangeDescription[]> {
const originalElement = <OsmWay>await OsmObject.DownloadObjectAsync(this.wayId)
const originalNodes = originalElement.nodes;
// First, calculate splitpoints and remove points close to one another
const splitInfo = this.CalculateSplitCoordinates(originalElement, this._toleranceInMeters)
// Now we have a list with e.g.
// [ { originalIndex: 0}, {originalIndex: 1, doSplit: true}, {originalIndex: 2}, {originalIndex: undefined, doSplit: true}, {originalIndex: 3}]
// Lets change 'originalIndex' to the actual node id first (or assign a new id if needed):
for (const element of splitInfo) {
if (element.originalIndex >= 0) {
element.originalIndex = originalElement.nodes[element.originalIndex]
} else {
element.originalIndex = changes.getNewID();
}
}
// Next up is creating actual parts from this
const wayParts: SplitInfo[][] = SplitAction.SegmentSplitInfo(splitInfo);
// Allright! At this point, we have our new ways!
// Which one is the longest of them (and can keep the id)?
let longest = undefined;
for (const wayPart of wayParts) {
if (longest === undefined) {
longest = wayPart;
continue
}
if (wayPart.length > longest.length) {
longest = wayPart
}
}
const changeDescription: ChangeDescription[] = []
// Let's create the new points as needed
for (const element of splitInfo) {
if (element.originalIndex >= 0) {
continue;
}
changeDescription.push({
type: "node",
id: element.originalIndex,
changes: {
lon: element.lngLat[0],
lat: element.lngLat[1]
},
meta: this._meta
})
}
// The ids of all the ways (including the original)
const allWayIdsInOrder: number[] = []
const allWaysNodesInOrder: number[][] = []
// Lets create OsmWays based on them
for (const wayPart of wayParts) {
let isOriginal = wayPart === longest
if (isOriginal) {
// We change the actual element!
const nodeIds = wayPart.map(p => p.originalIndex)
changeDescription.push({
type: "way",
id: originalElement.id,
changes: {
coordinates: wayPart.map(p => p.lngLat),
nodes: nodeIds
},
meta: this._meta
})
allWayIdsInOrder.push(originalElement.id)
allWaysNodesInOrder.push(nodeIds)
} else {
let id = changes.getNewID();
// Copy the tags from the original object onto the new
const kv = []
for (const k in originalElement.tags) {
if (!originalElement.tags.hasOwnProperty(k)) {
continue
}
if (k.startsWith("_") || k === "id") {
continue;
}
kv.push({k: k, v: originalElement.tags[k]})
}
const nodeIds = wayPart.map(p => p.originalIndex)
changeDescription.push({
type: "way",
id: id,
tags: kv,
changes: {
coordinates: wayPart.map(p => p.lngLat),
nodes: nodeIds
},
meta: this._meta
})
allWayIdsInOrder.push(id)
allWaysNodesInOrder.push(nodeIds)
}
}
// At last, we still have to check that we aren't part of a relation...
// At least, the order of the ways is identical, so we can keep the same roles
const relations = await OsmObject.DownloadReferencingRelations(this.wayId)
for (const relation of relations) {
const changDescrs = await new RelationSplitHandler({
relation: relation,
allWayIdsInOrder: allWayIdsInOrder,
originalNodes: originalNodes,
allWaysNodesInOrder: allWaysNodesInOrder,
originalWayId: originalElement.id,
}, this._meta.theme).CreateChangeDescriptions(changes)
changeDescription.push(...changDescrs)
}
// And we have our objects!
// Time to upload
return changeDescription
}
/**
* Calculates the actual points to split
* If another point is closer then ~5m, we reuse that point
*/
private CalculateSplitCoordinates(osmWay: OsmWay, toleranceInM = 5): SplitInfo[] {
const wayGeoJson = osmWay.asGeoJson()
// Should be [lon, lat][]
const originalPoints: [number, number][] = osmWay.coordinates.map(c => [c[1], c[0]])
const allPoints: {
// lon, lat
coordinates: [number, number],
isSplitPoint: boolean,
originalIndex?: number, // Original index
dist: number, // Distance from the nearest point on the original line
location: number // Distance from the start of the way
}[] = this._splitPointsCoordinates.map(c => {
// From the turf.js docs:
// The properties object will contain three values:
// - `index`: closest point was found on nth line part,
// - `dist`: distance between pt and the closest point,
// `location`: distance along the line between start and the closest point.
let projected = GeoOperations.nearestPoint(wayGeoJson, c)
// c is lon lat
return ({
coordinates: c,
isSplitPoint: true,
dist: projected.properties.dist,
location: projected.properties.location
});
})
// We have a bunch of coordinates here: [ [lon, lon], [lat, lon], ...] ...
// We project them onto the line (which should yield pretty much the same point and add them to allPoints
for (let i = 0; i < originalPoints.length; i++) {
let originalPoint = originalPoints[i];
let projected = GeoOperations.nearestPoint(wayGeoJson, originalPoint)
allPoints.push({
coordinates: originalPoint,
isSplitPoint: false,
location: projected.properties.location,
originalIndex: i,
dist: projected.properties.dist
})
}
// At this point, we have a list of both the split point and the old points, with some properties to discriminate between them
// We sort this list so that the new points are at the same location
allPoints.sort((a, b) => a.location - b.location)
for (let i = allPoints.length - 2; i >= 1; i--) {
// We 'merge' points with already existing nodes if they are close enough to avoid closeby elements
// Note the loop bounds: we skip the first two and last two elements:
// The first and last element are always part of the original way and should be kept
// Furthermore, we run in reverse order as we'll delete elements on the go
const point = allPoints[i]
if (point.originalIndex !== undefined) {
// We keep the original points
continue
}
// At this point, 'dist' told us the point is pretty close to an already existing point.
// Lets see which (already existing) point is closer and mark it as splitpoint
const nextPoint = allPoints[i + 1]
const prevPoint = allPoints[i - 1]
const distToNext = nextPoint.location - point.location
const distToPrev = point.location - prevPoint.location
if (distToNext * 1000 > toleranceInM && distToPrev * 1000 > toleranceInM) {
// Both are too far away to mark them as the split point
continue;
}
let closest = nextPoint
if (distToNext > distToPrev) {
closest = prevPoint
}
// Ok, we have a closest point!
if (closest.originalIndex === 0 || closest.originalIndex === originalPoints.length) {
// We can not split on the first or last points...
continue
}
closest.isSplitPoint = true;
allPoints.splice(i, 1)
}
const splitInfo: SplitInfo[] = []
let nextId = -1 // Note: these IDs are overwritten later on, no need to use a global counter here
for (const p of allPoints) {
let index = p.originalIndex
if (index === undefined) {
index = nextId;
nextId--;
}
const splitInfoElement = {
originalIndex: index,
lngLat: p.coordinates,
doSplit: p.isSplitPoint
}
splitInfo.push(splitInfoElement)
}
return splitInfo
}
}