def processAlgorithm(self, parameters, context, feedback):
source = self.parameterAsSource(parameters, self.PrmInputLayer, context)
preserve_final_pt = self.parameterAsBool(parameters, self.PrmPreserveFinalPoint, context)
min_distance = self.parameterAsDouble(parameters, self.PrmMinDistance, context)
units = self.parameterAsInt(parameters, self.PrmUnitsOfMeasure, context)
# Get the minimum distance in meters
min_distance = min_distance * conversionToMeters(units)
wkbtype = source.wkbType()
num_bad = 0
if QgsWkbTypes.geometryType(wkbtype) != QgsWkbTypes.LineGeometry:
feedback.reportError(tr("Please select a valid line layer."))
return({})
layercrs = source.sourceCrs()
(sink, dest_id) = self.parameterAsSink(
parameters, self.PrmOutputLayer, context, source.fields(), wkbtype, layercrs)
if layercrs != epsg4326:
transto4326 = QgsCoordinateTransform(layercrs, epsg4326, QgsProject.instance())
transfrom4326 = QgsCoordinateTransform(epsg4326, layercrs, QgsProject.instance())
total = 100.0 / source.featureCount() if source.featureCount() else 0
iterator = source.getFeatures()
num_bad = 0
for cnt, feature in enumerate(iterator):
if feedback.isCanceled():
break
geom = feature.geometry()
# Force the geometry to be in degrees so that we can use the geodesic algorithms
if layercrs != epsg4326:
results = geom.transform(transto4326)
num_parts = geom.constGet().partCount()
# feedback.pushInfo('num_parts {}'.format(num_parts))
try:
fline = QgsFeature()
fgeom = QgsGeometry()
is_valid = False
for part in geom.constGet().parts():
vertex_cnt = part.vertexCount()
# feedback.pushInfo('vertex_cnt {}'.format(vertex_cnt))
if vertex_cnt <= 1: # line of 1 or less points is invalid
continue
pts = []
for vcnt, vertex in enumerate(part.vertices()):
if vcnt == 0:
# This is the first point so we will save it
pts.append(vertex)
ptLast = vertex
else:
ptNext = vertex
gline = geod.InverseLine(ptLast.y(), ptLast.x(), ptNext.y(), ptNext.x())
if gline.s13 >= min_distance:
pts.append(ptNext)
ptLast = ptNext
elif (vcnt == vertex_cnt - 1) and preserve_final_pt:
if len(pts) >= 2:
# We have two or more points already on our pts list. Check to see if
# the next to last entry distance and the end point are greater than the
# the minimum distance. If so replace the last entry with this one else
# because the user has selected to preserve the last end point we will
# accept the end point.
gline = geod.InverseLine(pts[-2].y(), pts[-2].x(), ptNext.y(), ptNext.x())
if gline.s13 >= min_distance:
pts[-1] = ptNext
else:
pts.append(ptNext)
elif len(pts) == 1:
# We have only the beginning point of the line and because the user has
# selected that the last point to be preserved we will allow a distance less
# than the minimum so that the line can be preserved.
pts.append(ptNext)
if len(pts) > 1: # There must be more than one point to make a valid line
fgeom.addPoints(pts, QgsWkbTypes.LineGeometry)
is_valid = True
if is_valid: # Only save the feature if it is valid
fline.setAttributes(feature.attributes())
if layercrs != epsg4326:
fgeom.transform(transfrom4326)
fline.setGeometry(fgeom)
sink.addFeature(fline)
else:
num_bad += 1
except Exception:
'''s = traceback.format_exc()
feedback.pushInfo(s)'''
num_bad += 1
feedback.setProgress(int(cnt * total))
if num_bad > 0:
feedback.pushInfo(tr("{} out of {} features from input layer were invalid and were skipped.".format(num_bad, source.featureCount())))
return {self.PrmOutputLayer: dest_id}
