本文整理汇总了Python中qgis.core.QgsGeometry.isNull方法的典型用法代码示例。如果您正苦于以下问题：Python QgsGeometry.isNull方法的具体用法？Python QgsGeometry.isNull怎么用？Python QgsGeometry.isNull使用的例子？那么恭喜您, 这里精选的方法代码示例或许可以为您提供帮助。您也可以进一步了解该方法所在类qgis.core.QgsGeometry的用法示例。
在下文中一共展示了QgsGeometry.isNull方法的2个代码示例，这些例子默认根据受欢迎程度排序。您可以为喜欢或者感觉有用的代码点赞，您的评价将有助于系统推荐出更棒的Python代码示例。
示例1: processAlgorithm
# 需要导入模块: from qgis.core import QgsGeometry [as 别名]
# 或者: from qgis.core.QgsGeometry import isNull [as 别名]
def processAlgorithm(self, parameters, context, feedback):
source = self.parameterAsSource(parameters, self.INPUT, context)
fields = QgsFields()
fields.append(QgsField('POINTA', QVariant.Double, '', 24, 15))
fields.append(QgsField('POINTB', QVariant.Double, '', 24, 15))
fields.append(QgsField('POINTC', QVariant.Double, '', 24, 15))
(sink, dest_id) = self.parameterAsSink(parameters, self.OUTPUT, context,
fields, QgsWkbTypes.Polygon, source.sourceCrs())
pts = []
ptDict = {}
ptNdx = -1
c = voronoi.Context()
features = source.getFeatures()
total = 100.0 / source.featureCount() if source.featureCount() else 0
for current, inFeat in enumerate(features):
if feedback.isCanceled():
break
geom = QgsGeometry(inFeat.geometry())
if geom.isNull():
continue
if geom.isMultipart():
points = geom.asMultiPoint()
else:
points = [geom.asPoint()]
for n, point in enumerate(points):
x = point.x()
y = point.y()
pts.append((x, y))
ptNdx += 1
ptDict[ptNdx] = (inFeat.id(), n)
feedback.setProgress(int(current * total))
if len(pts) < 3:
raise QgsProcessingException(
self.tr('Input file should contain at least 3 points. Choose '
'another file and try again.'))
uniqueSet = set(item for item in pts)
ids = [pts.index(item) for item in uniqueSet]
sl = voronoi.SiteList([voronoi.Site(*i) for i in uniqueSet])
c.triangulate = True
voronoi.voronoi(sl, c)
triangles = c.triangles
feat = QgsFeature()
total = 100.0 / len(triangles) if triangles else 1
for current, triangle in enumerate(triangles):
if feedback.isCanceled():
break
indices = list(triangle)
indices.append(indices[0])
polygon = []
attrs = []
step = 0
for index in indices:
fid, n = ptDict[ids[index]]
request = QgsFeatureRequest().setFilterFid(fid)
inFeat = next(source.getFeatures(request))
geom = QgsGeometry(inFeat.geometry())
if geom.isMultipart():
point = QgsPointXY(geom.asMultiPoint()[n])
else:
point = QgsPointXY(geom.asPoint())
polygon.append(point)
if step <= 3:
attrs.append(ids[index])
step += 1
feat.setAttributes(attrs)
geometry = QgsGeometry().fromPolygonXY([polygon])
feat.setGeometry(geometry)
sink.addFeature(feat, QgsFeatureSink.FastInsert)
feedback.setProgress(int(current * total))
return {self.OUTPUT: dest_id}示例2: processAlgorithm
# 需要导入模块: from qgis.core import QgsGeometry [as 别名]
# 或者: from qgis.core.QgsGeometry import isNull [as 别名]
def processAlgorithm(self, parameters, context, feedback):
layer = QgsProcessingUtils.mapLayerFromString(self.getParameterValue(self.INPUT), context)
fields = QgsFields()
fields.append(QgsField('POINTA', QVariant.Double, '', 24, 15))
fields.append(QgsField('POINTB', QVariant.Double, '', 24, 15))
fields.append(QgsField('POINTC', QVariant.Double, '', 24, 15))
writer = self.getOutputFromName(self.OUTPUT).getVectorWriter(fields, QgsWkbTypes.Polygon, layer.crs(), context)
pts = []
ptDict = {}
ptNdx = -1
c = voronoi.Context()
features = QgsProcessingUtils.getFeatures(layer, context)
total = 100.0 / layer.featureCount() if layer.featureCount() else 0
for current, inFeat in enumerate(features):
geom = QgsGeometry(inFeat.geometry())
if geom.isNull():
continue
if geom.isMultipart():
points = geom.asMultiPoint()
else:
points = [geom.asPoint()]
for n, point in enumerate(points):
x = point.x()
y = point.y()
pts.append((x, y))
ptNdx += 1
ptDict[ptNdx] = (inFeat.id(), n)
feedback.setProgress(int(current * total))
if len(pts) < 3:
raise GeoAlgorithmExecutionException(
self.tr('Input file should contain at least 3 points. Choose '
'another file and try again.'))
uniqueSet = set(item for item in pts)
ids = [pts.index(item) for item in uniqueSet]
sl = voronoi.SiteList([voronoi.Site(*i) for i in uniqueSet])
c.triangulate = True
voronoi.voronoi(sl, c)
triangles = c.triangles
feat = QgsFeature()
total = 100.0 / len(triangles) if triangles else 1
for current, triangle in enumerate(triangles):
indices = list(triangle)
indices.append(indices[0])
polygon = []
attrs = []
step = 0
for index in indices:
fid, n = ptDict[ids[index]]
request = QgsFeatureRequest().setFilterFid(fid)
inFeat = next(layer.getFeatures(request))
geom = QgsGeometry(inFeat.geometry())
if geom.isMultipart():
point = QgsPointXY(geom.asMultiPoint()[n])
else:
point = QgsPointXY(geom.asPoint())
polygon.append(point)
if step <= 3:
attrs.append(ids[index])
step += 1
feat.setAttributes(attrs)
geometry = QgsGeometry().fromPolygon([polygon])
feat.setGeometry(geometry)
writer.addFeature(feat, QgsFeatureSink.FastInsert)
feedback.setProgress(int(current * total))
del writer