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Python QgsGeometry.area方法代码示例

本文整理汇总了Python中qgis.core.QgsGeometry.area方法的典型用法代码示例。如果您正苦于以下问题:Python QgsGeometry.area方法的具体用法?Python QgsGeometry.area怎么用?Python QgsGeometry.area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qgis.core.QgsGeometry的用法示例。


在下文中一共展示了QgsGeometry.area方法的1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 area [as 别名]

#.........这里部分代码省略.........

        # We go through the list and see if we find any polygons we can
        # merge the selected with. If we have no success with some we
        # merge and then restart the whole story.
        while madeProgress:  # Check if we made any progress
            madeProgress = False
            featNotEliminated = []

            # Iterate over the polygons to eliminate
            for i in range(len(featToEliminate)):
                feat = featToEliminate.pop()
                geom2Eliminate = QgsGeometry(feat.geometry())
                bbox = geom2Eliminate.boundingBox()
                fit = processLayer.getFeatures(
                    QgsFeatureRequest().setFilterRect(bbox))
                mergeWithFid = None
                mergeWithGeom = None
                max = 0
                min = -1
                selFeat = QgsFeature()

                while fit.nextFeature(selFeat):
                    selGeom = QgsGeometry(selFeat.geometry())

                    if geom2Eliminate.intersects(selGeom):
                        # We have a candidate
                        iGeom = geom2Eliminate.intersection(selGeom)

                        if iGeom is None:
                            continue

                        if boundary:
                            selValue = iGeom.length()
                        else:
                            # area. We need a common boundary in
                            # order to merge
                            if 0 < iGeom.length():
                                selValue = selGeom.area()
                            else:
                                selValue = -1

                        if -1 != selValue:
                            useThis = True

                            if smallestArea:
                                if -1 == min:
                                    min = selValue
                                else:
                                    if selValue < min:
                                        min = selValue
                                    else:
                                        useThis = False
                            else:
                                if selValue > max:
                                    max = selValue
                                else:
                                    useThis = False

                            if useThis:
                                mergeWithFid = selFeat.id()
                                mergeWithGeom = QgsGeometry(selGeom)
                # End while fit

                if mergeWithFid is not None:
                    # A successful candidate
                    newGeom = mergeWithGeom.combine(geom2Eliminate)

                    if processLayer.changeGeometry(mergeWithFid, newGeom):
                        madeProgress = True
                    else:
                        raise GeoAlgorithmExecutionException(
                            self.tr('Could not replace geometry of feature with id %s' % mergeWithFid))

                    start = start + add
                    progress.setPercentage(start)
                else:
                    featNotEliminated.append(feat)

            # End for featToEliminate

            featToEliminate = featNotEliminated

        # End while

        # Create output
        provider = processLayer.dataProvider()
        output = self.getOutputFromName(self.OUTPUT)
        writer = output.getVectorWriter(provider.fields(),
                                        provider.geometryType(), processLayer.crs())

        # Write all features that are left over to output layer
        iterator = processLayer.getFeatures()
        for feature in iterator:
            writer.addFeature(feature)

        # Leave processLayer untouched
        processLayer.rollBack()

        for feature in featNotEliminated:
            writer.addFeature(feature)
开发者ID:dudds6699,项目名称:QGIS,代码行数:104,代码来源:Eliminate.py


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