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[processing] Fix "Random points along line" alg

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Avoid various errors in case of empty input layer, empty/null geometries, invalid geometries, linestrings with zero-length segments...
This commit is contained in:
Andrea Giudiceandrea 2024-03-04 19:09:30 +01:00 committed by Nyall Dawson
parent a4f1707d46
commit 9c32e69f88
1 changed files with 19 additions and 5 deletions
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24
python/plugins/processing/algs/qgis/RandomPointsAlongLines.py
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@ -100,7 +100,6 @@ class RandomPointsAlongLines(QgisAlgorithm):
nPoints = 0 nPoints = 0
nIterations = 0 nIterations = 0
maxIterations = pointCount * 200 maxIterations = pointCount * 200
featureCount = source.featureCount()
total = 100.0 / pointCount if pointCount else 1 total = 100.0 / pointCount if pointCount else 1
index = QgsSpatialIndex() index = QgsSpatialIndex()
@ -116,14 +115,22 @@ class RandomPointsAlongLines(QgisAlgorithm):
ids = source.allFeatureIds() ids = source.allFeatureIds()
while nIterations < maxIterations and nPoints < pointCount: while ids and nIterations < maxIterations and nPoints < pointCount:
if feedback.isCanceled(): if feedback.isCanceled():
break break
# pick random feature # pick random feature
fid = random.choice(ids) fid = random.choice(ids)
f = next(source.getFeatures(request.setFilterFid(fid).setSubsetOfAttributes([]))) try:
f = next(source.getFeatures(request.setFilterFid(fid).setSubsetOfAttributes([])))
except:
ids.remove(fid)
continue
fGeom = f.geometry() fGeom = f.geometry()
if fGeom.isEmpty():
ids.remove(fid)
continue
if fGeom.isMultipart(): if fGeom.isMultipart():
lines = fGeom.asMultiPolyline() lines = fGeom.asMultiPolyline()
@ -134,13 +141,20 @@ class RandomPointsAlongLines(QgisAlgorithm):
vertices = fGeom.asPolyline() vertices = fGeom.asPolyline()
# pick random segment # pick random segment
if len(vertices) == 2: nVertices = len(vertices)
if nVertices < 2:
nIterations += 1
continue
if nVertices == 2:
vid = 0 vid = 0
else: else:
vid = random.randint(0, len(vertices) - 2) vid = random.randint(0, nVertices - 2)
startPoint = vertices[vid] startPoint = vertices[vid]
endPoint = vertices[vid + 1] endPoint = vertices[vid + 1]
length = da.measureLine(startPoint, endPoint) length = da.measureLine(startPoint, endPoint)
if length == 0:
nIterations += 1
continue
dist = length * random.random() dist = length * random.random()
d = dist / (length - dist) d = dist / (length - dist)