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Optimise calculation of envelopes for MinimumBoundingGeometry alg

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It's more efficient to calculate these on the fly, rather then
collecting all geometry points and then calculating.
This commit is contained in:
Nyall Dawson 2017-09-03 18:31:31 +10:00
parent 83affdc7f5
commit b6e35428e2
1 changed files with 62 additions and 21 deletions
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83
python/plugins/processing/algs/qgis/MinimumBoundingGeometry.py
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@ -38,6 +38,7 @@ from qgis.core import (QgsField,
QgsWkbTypes,
QgsFeatureRequest,
QgsFields,
QgsRectangle,
QgsProcessingParameterFeatureSource,
QgsProcessingParameterField,
QgsProcessingParameterEnum,
@ -53,7 +54,6 @@ pluginPath = os.path.split(os.path.split(os.path.dirname(__file__))[0])[0]
class MinimumBoundingGeometry(QgisAlgorithm):
INPUT = 'INPUT'
OUTPUT = 'OUTPUT'
TYPE = 'TYPE'
@ -76,11 +76,13 @@ class MinimumBoundingGeometry(QgisAlgorithm):
self.addParameter(QgsProcessingParameterFeatureSource(self.INPUT,
self.tr('Input layer')))
self.addParameter(QgsProcessingParameterField(self.FIELD,
self.tr('Field (optional, set if features should be grouped by class)'),
self.tr(
'Field (optional, set if features should be grouped by class)'),
parentLayerParameterName=self.INPUT, optional=True))
self.addParameter(QgsProcessingParameterEnum(self.TYPE,
self.tr('Geometry type'), options=self.type_names))
self.addParameter(QgsProcessingParameterFeatureSink(self.OUTPUT, self.tr('Bounding geometry'), QgsProcessing.TypeVectorPolygon))
self.addParameter(QgsProcessingParameterFeatureSink(self.OUTPUT, self.tr('Bounding geometry'),
QgsProcessing.TypeVectorPolygon))
def name(self):
return 'minimumboundinggeometry'
@ -89,7 +91,9 @@ class MinimumBoundingGeometry(QgisAlgorithm):
return self.tr('Minimum bounding geometry')
def tags(self):
return self.tr('bounding,box,bounds,envelope,minimum,oriented,rectangle,enclosing,circle,convex,hull,generalization').split(',')
return self.tr(
'bounding,box,bounds,envelope,minimum,oriented,rectangle,enclosing,circle,convex,hull,generalization').split(
',')
def processAlgorithm(self, parameters, context, feedback):
source = self.parameterAsSource(parameters, self.INPUT, context)
@ -108,13 +112,13 @@ class MinimumBoundingGeometry(QgisAlgorithm):
if field_index >= 0:
fields.append(source.fields()[field_index])
if type == 0:
#envelope
# envelope
fields.append(QgsField('width', QVariant.Double, '', 20, 6))
fields.append(QgsField('height', QVariant.Double, '', 20, 6))
fields.append(QgsField('area', QVariant.Double, '', 20, 6))
fields.append(QgsField('perimeter', QVariant.Double, '', 20, 6))
elif type == 1:
#oriented rect
# oriented rect
fields.append(QgsField('width', QVariant.Double, '', 20, 6))
fields.append(QgsField('height', QVariant.Double, '', 20, 6))
fields.append(QgsField('angle', QVariant.Double, '', 20, 6))
@ -134,6 +138,7 @@ class MinimumBoundingGeometry(QgisAlgorithm):
if field_index >= 0:
geometry_dict = {}
bounds_dict = {}
total = 50.0 / source.featureCount() if source.featureCount() else 1
features = source.getFeatures(QgsFeatureRequest().setSubsetOfAttributes([field_index]))
for current, f in enumerate(features):
@ -143,29 +148,56 @@ class MinimumBoundingGeometry(QgisAlgorithm):
if not f.hasGeometry():
continue
if not f.attributes()[field_index] in geometry_dict:
geometry_dict[f.attributes()[field_index]] = [f.geometry()]
if type == 0:
# bounding boxes - calculate on the fly for efficiency
if not f.attributes()[field_index] in bounds_dict:
bounds_dict[f.attributes()[field_index]] = f.geometry().boundingBox()
else:
bounds_dict[f.attributes()[field_index]].combineExtentWith(f.geometry().boundingBox())
else:
geometry_dict[f.attributes()[field_index]].append(f.geometry())
if not f.attributes()[field_index] in geometry_dict:
geometry_dict[f.attributes()[field_index]] = [f.geometry()]
else:
geometry_dict[f.attributes()[field_index]].append(f.geometry())
feedback.setProgress(int(current * total))
current = 0
total = 50.0 / len(geometry_dict) if geometry_dict else 1
for group, geometries in geometry_dict.items():
if feedback.isCanceled():
break
if type == 0:
# bounding boxes
current = 0
total = 50.0 / len(bounds_dict) if bounds_dict else 1
for group, rect in bounds_dict.items():
if feedback.isCanceled():
break
feature = self.createFeature(feedback, current, type, geometries, group)
sink.addFeature(feature, QgsFeatureSink.FastInsert)
geometry_dict[group] = None
# envelope
feature = QgsFeature()
feature.setGeometry(QgsGeometry.fromRect(rect))
feature.setAttributes([current, group, rect.width(), rect.height(), rect.area(), rect.perimeter()])
sink.addFeature(feature, QgsFeatureSink.FastInsert)
geometry_dict[group] = None
feedback.setProgress(50 + int(current * total))
current += 1
feedback.setProgress(50 + int(current * total))
current += 1
else:
current = 0
total = 50.0 / len(geometry_dict) if geometry_dict else 1
for group, geometries in geometry_dict.items():
if feedback.isCanceled():
break
feature = self.createFeature(feedback, current, type, geometries, group)
sink.addFeature(feature, QgsFeatureSink.FastInsert)
geometry_dict[group] = None
feedback.setProgress(50 + int(current * total))
current += 1
else:
total = 80.0 / source.featureCount() if source.featureCount() else 1
features = source.getFeatures(QgsFeatureRequest().setSubsetOfAttributes([]))
geometry_queue = []
bounds = QgsRectangle()
for current, f in enumerate(features):
if feedback.isCanceled():
break
@ -173,11 +205,20 @@ class MinimumBoundingGeometry(QgisAlgorithm):
if not f.hasGeometry():
continue
geometry_queue.append(f.geometry())
if type == 0:
# bounding boxes, calculate on the fly for efficiency
bounds.combineExtentWith(f.geometry().boundingBox())
else:
geometry_queue.append(f.geometry())
feedback.setProgress(int(current * total))
if not feedback.isCanceled():
feature = self.createFeature(feedback, 0, type, geometry_queue)
if type == 0:
feature = QgsFeature()
feature.setGeometry(QgsGeometry.fromRect(bounds))
feature.setAttributes([0, bounds.width(), bounds.height(), bounds.area(), bounds.perimeter()])
else:
feature = self.createFeature(feedback, 0, type, geometry_queue)
sink.addFeature(feature, QgsFeatureSink.FastInsert)
return {self.OUTPUT: dest_id}