Skip to content

Commit

Permalink
switch dual midpoint smoother to squashVertex
Browse files Browse the repository at this point in the history
  • Loading branch information
@msbarry
msbarry committed Dec 4, 2024
1 parent e482476 commit 1d0bc0c
Showing 1 changed file with 66 additions and 74 deletions.
140 changes: 66 additions & 74 deletions planetiler-core/src/main/java/com/onthegomap/planetiler/geo/DualMidpointSmoother.java
View file
Original file line number Diff line number Diff line change
Expand Up @@ -116,88 +116,36 @@ protected CoordinateSequence transformCoordinates(CoordinateSequence coords, Geo
if (coords.size() <= 2) {
return coords.copy();
}
boolean checkVertices = minSquaredVertexTolerance > 0 || minVertexArea > 0 || maxSquaredOffset > 0 || maxArea > 0;
for (int iter = 0; iter < iters; iter++) {
MutableCoordinateSequence result = new MutableCoordinateSequence();
if (!area) {
result.addPoint(coords.getX(0), coords.getY(0));
}
int last = coords.size() - 1;
double x2 = coords.getX(0);
double y2 = coords.getY(0);
double nextA = a;
boolean skippedLastVertex = false;
double x1, y1;
for (int i = 0; i < last; i++) {
double x2 = coords.getX(0), y2 = coords.getY(0);
double x3 = coords.getX(1), y3 = coords.getY(1);
// for lines, always add the first point but for polygons this is a placeholder that will be updated
// when last vertex is squashed
result.addPoint(x2, y2);
for (int i = 1; i < last; i++) {
x1 = x2;
y1 = y2;
x2 = coords.getX(i + 1);
y2 = coords.getY(i + 1);
double dx = x2 - x1;
double dy = y2 - y1;

if ((area || i > 0) && !skippedLastVertex) {
result.addPoint(x1 + dx * nextA, y1 + dy * nextA);
}
nextA = a;

if (area || i < last - 1) {
double nextB = b;
if (checkVertices) {
int next = i < last - 1 ? (i + 2) : 1;
double x3 = coords.getX(next);
double y3 = coords.getY(next);
if (skipVertex(x1, y1, x2, y2, x3, y3)) {
result.addPoint(x2, y2);
skippedLastVertex = true;
continue;
}
skippedLastVertex = false;

// check the amount of error introduced by removing this vertex (either by offset or area)
// and if it is too large, then move nextA/nextB ratios closer to the vertex to limit the error
if (maxArea > 0 || maxSquaredOffset > 0) {
double magA = Math.hypot(x2 - x1, y2 - y1);
double magB = Math.hypot(x3 - x2, y3 - y2);
double den = magA * magB;
double aDist = magA * (1 - b);
double bDist = magB * a;
double maxDistSquared = Double.POSITIVE_INFINITY;
if (maxArea > 0) {
double sin = den <= 0 ? 0 : Math.abs(((x1 - x2) * (y3 - y2)) - ((y1 - y2) * (x3 - x2))) / den;
maxDistSquared = 2 * maxArea / sin;
}
if (maxSquaredOffset > 0) {
double cos = den <= 0 ? 0 : Math.clamp(((x1 - x2) * (x3 - x2) + (y1 - y2) * (y3 - y2)) / den, -1, 1);
maxDistSquared = Math.min(maxDistSquared, 2 * maxSquaredOffset / (1 + cos));
}
double maxDist = Double.NaN;
if (aDist * aDist > maxDistSquared) {
nextB = 1 - (maxDist = Math.sqrt(maxDistSquared)) / magA;
}
if (bDist * bDist > maxDistSquared) {
if (Double.isNaN(maxDist)) {
maxDist = Math.sqrt(maxDistSquared);
}
nextA = maxDist / magA;
}
}
}

result.addPoint(x1 + dx * nextB, y1 + dy * nextB);
}
x2 = x3;
y2 = y3;
x3 = coords.getX(i + 1);
y3 = coords.getY(i + 1);
squashVertex(result, x1, y1, x2, y2, x3, y3);
}
if (area) {
if (skippedLastVertex) {
result.setX(0, result.getX(result.size() - 1));
result.setY(0, result.getY(result.size() - 1));
} else {
if (nextA != a) {
result.setX(0, (coords.getX(1) - coords.getX(0)) * nextA);
result.setY(0, (coords.getY(1) - coords.getY(0)) * nextA);
}
result.closeRing();
}
squashVertex(result,
coords.getX(last - 1),
coords.getY(last - 1),
coords.getX(0),
coords.getY(0),
coords.getX(1),
coords.getY(1)
);
int idx = result.size() - 1;
result.setX(0, result.getX(idx));
result.setY(0, result.getY(idx));
} else {
result.addPoint(coords.getX(last), coords.getY(last));
}
Expand All @@ -210,6 +158,50 @@ protected CoordinateSequence transformCoordinates(CoordinateSequence coords, Geo
return coords;
}

private void squashVertex(MutableCoordinateSequence result, double x1, double y1, double x2, double y2, double x3,
double y3) {

if (skipVertex(x1, y1, x2, y2, x3, y3)) {
result.addPoint(x2, y2);
return;
}

double nextB = b;
double nextA = a;

// check the amount of error introduced by removing this vertex (either by offset or area)
// and if it is too large, then move nextA/nextB ratios closer to the vertex to limit the error
if (maxArea > 0 || maxSquaredOffset > 0) {
double magA = Math.hypot(x2 - x1, y2 - y1);
double magB = Math.hypot(x3 - x2, y3 - y2);
double den = magA * magB;
double aDist = magA * (1 - b);
double bDist = magB * a;
double maxDistSquared = Double.POSITIVE_INFINITY;
if (maxArea > 0) {
double sin = den <= 0 ? 0 : Math.abs(((x1 - x2) * (y3 - y2)) - ((y1 - y2) * (x3 - x2))) / den;
maxDistSquared = 2 * maxArea / sin;

Check warning on line 183 in planetiler-core/src/main/java/com/onthegomap/planetiler/geo/DualMidpointSmoother.java

View workflow job for this annotation

GitHub Actions / Analyze with Sonar

CRITICAL BUG 

Make sure "sin" can't be zero before doing this division.

rule: java:S3518 (https://sonarcloud.io/organizations/onthegomap/rules?open=java%3AS3518&rule_key=java%3AS3518)
issue url: https://sonarcloud.io/project/issues?pullRequest=1118&open=AZOR6g9U3cbatTPvm6KP&id=onthegomap_planetiler
}
if (maxSquaredOffset > 0) {
double cos = den <= 0 ? 0 : Math.clamp(((x1 - x2) * (x3 - x2) + (y1 - y2) * (y3 - y2)) / den, -1, 1);
maxDistSquared = Math.min(maxDistSquared, 2 * maxSquaredOffset / (1 + cos));
}
double maxDist = Double.NaN;
if (aDist * aDist > maxDistSquared) {
nextB = 1 - (maxDist = Math.sqrt(maxDistSquared)) / magA;
}
if (bDist * bDist > maxDistSquared) {
if (Double.isNaN(maxDist)) {
maxDist = Math.sqrt(maxDistSquared);
}
nextA = maxDist / magA;
}
}

result.addPoint(x1 + (x2 - x1) * nextB, y1 + (y2 - y1) * nextB);
result.addPoint(x2 + (x3 - x2) * nextA, y2 + (y3 - y2) * nextA);
}

private boolean skipVertex(double x1, double y1, double x2, double y2, double x3, double y3) {
return (minVertexArea > 0 && VWSimplifier.triangleArea(x1, y1, x2, y2, x3, y3) < minVertexArea) ||
(minSquaredVertexTolerance > 0 &&
Expand Down

0 comments on commit 1d0bc0c

Please sign in to comment.