def validateQgsExpressions(self, qgsExpression):
exp = QgsExpression(qgsExpression)
if exp.isValid():
if exp.isField():
return False
return True
return False
def processAlgorithm(self, parameters, context, feedback):
source = self.parameterAsSource(parameters, self.INPUT, context)
if source is None:
raise QgsProcessingException(
self.invalidSourceError(parameters, self.INPUT))
close_path = self.parameterAsBool(parameters, self.CLOSE_PATH, context)
group_field_name = self.parameterAsString(parameters, self.GROUP_FIELD,
context)
order_field_name = self.parameterAsString(parameters, self.ORDER_FIELD,
context)
order_expression = self.parameterAsString(parameters,
self.ORDER_EXPRESSION,
context)
date_format = self.parameterAsString(parameters, self.DATE_FORMAT,
context)
text_dir = self.parameterAsString(parameters, self.OUTPUT_TEXT_DIR,
context)
group_field_index = source.fields().lookupField(group_field_name)
if group_field_index >= 0:
group_field_def = source.fields().at(group_field_index)
else:
group_field_def = None
if order_field_name:
order_expression = QgsExpression.quotedColumnRef(order_field_name)
if not order_expression:
raise QgsProcessingException(
self.tr('ORDER_EXPRESSION parameter is missing.'))
expression_context = self.createExpressionContext(
parameters, context, source)
expression = QgsExpression(order_expression)
if expression.hasParserError():
raise QgsProcessingException(expression.parserErrorString())
expression.prepare(expression_context)
order_field_type = QVariant.String
if expression.isField():
field_name = next(iter(expression.referencedColumns()))
order_field_type = source.fields().field(field_name).type()
fields = QgsFields()
if group_field_def is not None:
fields.append(group_field_def)
begin_field = QgsField('begin', order_field_type)
fields.append(begin_field)
end_field = QgsField('end', order_field_type)
fields.append(end_field)
output_wkb = QgsWkbTypes.LineString
if QgsWkbTypes.hasM(source.wkbType()):
output_wkb = QgsWkbTypes.addM(output_wkb)
if QgsWkbTypes.hasZ(source.wkbType()):
output_wkb = QgsWkbTypes.addZ(output_wkb)
(sink, dest_id) = self.parameterAsSink(parameters, self.OUTPUT,
context, fields, output_wkb,
source.sourceCrs())
if sink is None:
raise QgsProcessingException(
self.invalidSinkError(parameters, self.OUTPUT))
if text_dir and not (os.path.exists(text_dir)):
raise QgsProcessingException(
self.tr("The text output directory does not exist"))
points = dict()
required_fields = expression.referencedColumns()
required_fields.add(group_field_name)
features = source.getFeatures(
QgsFeatureRequest().setSubsetOfAttributes(required_fields,
source.fields()),
QgsProcessingFeatureSource.FlagSkipGeometryValidityChecks)
total = 100.0 / source.featureCount() if source.featureCount() else 0
for current, f in enumerate(features):
if feedback.isCanceled():
break
if not f.hasGeometry():
continue
point = f.geometry().constGet().clone()
if group_field_index >= 0:
group = f[group_field_index]
else:
group = 1
expression_context.setFeature(f)
order = expression.evaluate(expression_context)
if date_format != '':
order = datetime.strptime(str(order), date_format)
if group in points:
points[group].append((order, point))
else:
points[group] = [(order, point)]
feedback.setProgress(int(current * total))
feedback.setProgress(0)
da = QgsDistanceArea()
da.setSourceCrs(source.sourceCrs(), context.transformContext())
da.setEllipsoid(context.ellipsoid())
current = 0
total = 100.0 / len(points) if points else 1
for group, vertices in points.items():
if feedback.isCanceled():
break
vertices.sort(key=lambda x: (x[0] is None, x[0]))
f = QgsFeature()
attributes = []
if group_field_index >= 0:
attributes.append(group)
attributes.extend([vertices[0][0], vertices[-1][0]])
f.setAttributes(attributes)
line = [node[1] for node in vertices]
if close_path is True:
if line[0] != line[-1]:
line.append(line[0])
if text_dir:
fileName = os.path.join(text_dir, '%s.txt' % group)
with open(fileName, 'w') as fl:
fl.write('angle=Azimuth\n')
fl.write('heading=Coordinate_System\n')
fl.write('dist_units=Default\n')
for i in range(len(line)):
if i == 0:
fl.write('startAt=%f;%f;90\n' %
(line[i].x(), line[i].y()))
fl.write('survey=Polygonal\n')
fl.write('[data]\n')
else:
angle = line[i - 1].azimuth(line[i])
distance = da.measureLine(QgsPointXY(line[i - 1]),
QgsPointXY(line[i]))
fl.write('%f;%f;90\n' % (angle, distance))
f.setGeometry(QgsGeometry(QgsLineString(line)))
sink.addFeature(f, QgsFeatureSink.FastInsert)
current += 1
feedback.setProgress(int(current * total))
return {self.OUTPUT: dest_id}
