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simplify slope segment

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vcoppe
2024-06-28 18:40:43 +02:00
parent f2014f53a1
commit cbc5c05807
3 changed files with 11 additions and 17 deletions
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20
gpx/src/simplify.ts
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@@ -5,7 +5,7 @@ export type SimplifiedTrackPoint = { point: TrackPoint, distance?: number };
const earthRadius = 6371008.8;
export function ramerDouglasPeucker(points: readonly TrackPoint[], epsilon: number = 50, measure: (a: TrackPoint, b: TrackPoint, c: TrackPoint) => number = computeCrossarc, canSplit: (a: TrackPoint, b: TrackPoint, c: TrackPoint) => boolean = () => true): SimplifiedTrackPoint[] {
export function ramerDouglasPeucker(points: readonly TrackPoint[], epsilon: number = 50, measure: (a: TrackPoint, b: TrackPoint, c: TrackPoint) => number = computeCrossarc): SimplifiedTrackPoint[] {
if (points.length == 0) {
return [];
} else if (points.length == 1) {
@@ -17,33 +17,31 @@ export function ramerDouglasPeucker(points: readonly TrackPoint[], epsilon: numb
let simplified = [{
point: points[0]
}];
ramerDouglasPeuckerRecursive(points, epsilon, measure, canSplit, 0, points.length - 1, simplified);
ramerDouglasPeuckerRecursive(points, epsilon, measure, 0, points.length - 1, simplified);
simplified.push({
point: points[points.length - 1]
});
return simplified;
}
function ramerDouglasPeuckerRecursive(points: readonly TrackPoint[], epsilon: number, measure: (a: TrackPoint, b: TrackPoint, c: TrackPoint) => number, canSplit: (a: TrackPoint, b: TrackPoint, c: TrackPoint) => boolean, start: number, end: number, simplified: SimplifiedTrackPoint[]) {
function ramerDouglasPeuckerRecursive(points: readonly TrackPoint[], epsilon: number, measure: (a: TrackPoint, b: TrackPoint, c: TrackPoint) => number, start: number, end: number, simplified: SimplifiedTrackPoint[]) {
let largest = {
index: 0,
distance: 0
};
for (let i = start + 1; i < end; i++) {
if (canSplit(points[start], points[end], points[i])) {
let distance = measure(points[start], points[end], points[i]);
if (distance > largest.distance) {
largest.index = i;
largest.distance = distance;
}
let distance = measure(points[start], points[end], points[i]);
if (distance > largest.distance) {
largest.index = i;
largest.distance = distance;
}
}
if (largest.distance > epsilon && largest.index != 0) {
ramerDouglasPeuckerRecursive(points, epsilon, measure, canSplit, start, largest.index, simplified);
ramerDouglasPeuckerRecursive(points, epsilon, measure, start, largest.index, simplified);
simplified.push({ point: points[largest.index], distance: largest.distance });
ramerDouglasPeuckerRecursive(points, epsilon, measure, canSplit, largest.index, end, simplified);
ramerDouglasPeuckerRecursive(points, epsilon, measure, largest.index, end, simplified);
}
}