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3550cc99a6
Tags are used while searching in the toolbox. This should help with finding algorithms when the exact name is not known, eg you could search for "envelope" or "bounds" and find the 'Polygon from Layer Extent' algorithm. At the moment it's quite hard to discover algorithms which exist when you don't know what their called and have to instead search for every possible naming variant which could exist...
164 lines
5.8 KiB
Python
164 lines
5.8 KiB
Python
# -*- coding: utf-8 -*-
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"""
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***************************************************************************
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ExtentFromLayer.py
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---------------------
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Date : August 2012
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Copyright : (C) 2012 by Victor Olaya
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Email : volayaf at gmail dot com
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***************************************************************************
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* *
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* This program is free software; you can redistribute it and/or modify *
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* it under the terms of the GNU General Public License as published by *
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* the Free Software Foundation; either version 2 of the License, or *
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* (at your option) any later version. *
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* *
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***************************************************************************
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"""
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__author__ = 'Victor Olaya'
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__date__ = 'August 2012'
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__copyright__ = '(C) 2012, Victor Olaya'
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# This will get replaced with a git SHA1 when you do a git archive
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__revision__ = '$Format:%H$'
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import os
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from qgis.PyQt.QtGui import QIcon
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from qgis.PyQt.QtCore import QVariant
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from qgis.core import Qgis, QgsField, QgsPoint, QgsGeometry, QgsFeature, QgsWkbTypes
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from processing.core.GeoAlgorithm import GeoAlgorithm
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from processing.core.parameters import ParameterVector
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from processing.core.parameters import ParameterBoolean
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from processing.core.outputs import OutputVector
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from processing.tools import dataobjects, vector
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pluginPath = os.path.split(os.path.split(os.path.dirname(__file__))[0])[0]
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class ExtentFromLayer(GeoAlgorithm):
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INPUT_LAYER = 'INPUT_LAYER'
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BY_FEATURE = 'BY_FEATURE'
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OUTPUT = 'OUTPUT'
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def getIcon(self):
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return QIcon(os.path.join(pluginPath, 'images', 'ftools', 'layer_extent.png'))
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def defineCharacteristics(self):
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self.name, self.i18n_name = self.trAlgorithm('Polygon from layer extent')
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self.group, self.i18n_group = self.trAlgorithm('Vector general tools')
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self.tags = self.tr('extent,envelope,bounds,bounding,boundary,layer')
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self.addParameter(ParameterVector(self.INPUT_LAYER,
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self.tr('Input layer')))
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self.addParameter(ParameterBoolean(self.BY_FEATURE,
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self.tr('Calculate extent for each feature separately'), False))
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self.addOutput(OutputVector(self.OUTPUT, self.tr('Extent'), datatype=[dataobjects.TYPE_VECTOR_POLYGON]))
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def processAlgorithm(self, progress):
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layer = dataobjects.getObjectFromUri(
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self.getParameterValue(self.INPUT_LAYER))
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byFeature = self.getParameterValue(self.BY_FEATURE)
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fields = [
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QgsField('MINX', QVariant.Double),
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QgsField('MINY', QVariant.Double),
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QgsField('MAXX', QVariant.Double),
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QgsField('MAXY', QVariant.Double),
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QgsField('CNTX', QVariant.Double),
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QgsField('CNTY', QVariant.Double),
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QgsField('AREA', QVariant.Double),
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QgsField('PERIM', QVariant.Double),
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QgsField('HEIGHT', QVariant.Double),
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QgsField('WIDTH', QVariant.Double),
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]
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writer = self.getOutputFromName(self.OUTPUT).getVectorWriter(fields,
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QgsWkbTypes.Polygon, layer.crs())
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if byFeature:
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self.featureExtent(layer, writer, progress)
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else:
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self.layerExtent(layer, writer, progress)
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del writer
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def layerExtent(self, layer, writer, progress):
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rect = layer.extent()
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minx = rect.xMinimum()
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miny = rect.yMinimum()
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maxx = rect.xMaximum()
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maxy = rect.yMaximum()
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height = rect.height()
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width = rect.width()
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cntx = minx + width / 2.0
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cnty = miny + height / 2.0
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area = width * height
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perim = 2 * width + 2 * height
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rect = [QgsPoint(minx, miny), QgsPoint(minx, maxy), QgsPoint(maxx,
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maxy), QgsPoint(maxx, miny), QgsPoint(minx, miny)]
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geometry = QgsGeometry().fromPolygon([rect])
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feat = QgsFeature()
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feat.setGeometry(geometry)
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attrs = [
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minx,
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miny,
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maxx,
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maxy,
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cntx,
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cnty,
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area,
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perim,
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height,
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width,
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]
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feat.setAttributes(attrs)
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writer.addFeature(feat)
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def featureExtent(self, layer, writer, progress):
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features = vector.features(layer)
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total = 100.0 / len(features)
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feat = QgsFeature()
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for current, f in enumerate(features):
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rect = f.geometry().boundingBox()
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minx = rect.xMinimum()
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miny = rect.yMinimum()
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maxx = rect.xMaximum()
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maxy = rect.yMaximum()
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height = rect.height()
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width = rect.width()
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cntx = minx + width / 2.0
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cnty = miny + height / 2.0
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area = width * height
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perim = 2 * width + 2 * height
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rect = [QgsPoint(minx, miny), QgsPoint(minx, maxy), QgsPoint(maxx,
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maxy), QgsPoint(maxx, miny), QgsPoint(minx, miny)]
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geometry = QgsGeometry().fromPolygon([rect])
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feat.setGeometry(geometry)
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attrs = [
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minx,
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miny,
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maxx,
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maxy,
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cntx,
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cnty,
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area,
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perim,
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height,
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width,
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]
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feat.setAttributes(attrs)
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writer.addFeature(feat)
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progress.setPercentage(int(current * total))
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