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122 lines
5.1 KiB
Python
122 lines
5.1 KiB
Python
# -*- coding: utf-8 -*-
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"""
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***************************************************************************
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CreateConstantRaster.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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import math
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import struct
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from qgis.core import (Qgis,
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QgsErrorMessage,
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QgsProcessingException,
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QgsRasterBlock,
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QgsRasterFileWriter,
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QgsProcessingParameterExtent,
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QgsProcessingParameterNumber,
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QgsProcessingParameterCrs,
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QgsProcessingParameterRasterDestination)
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from processing.algs.qgis.QgisAlgorithm import QgisAlgorithm
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class CreateConstantRaster(QgisAlgorithm):
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EXTENT = 'EXTENT'
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TARGET_CRS = 'TARGET_CRS'
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PIXEL_SIZE = 'PIXEL_SIZE'
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NUMBER = 'NUMBER'
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OUTPUT = 'OUTPUT'
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def group(self):
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return self.tr('Raster tools')
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def groupId(self):
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return 'rastertools'
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def __init__(self):
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super().__init__()
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def initAlgorithm(self, config=None):
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self.addParameter(QgsProcessingParameterExtent(self.EXTENT,
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self.tr('Desired extent')))
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self.addParameter(QgsProcessingParameterCrs(self.TARGET_CRS,
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self.tr('Target CRS'),
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'ProjectCrs'))
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self.addParameter(QgsProcessingParameterNumber(self.PIXEL_SIZE,
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self.tr('Pixel size'),
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QgsProcessingParameterNumber.Double,
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0.1, False, 0.01, 999))
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self.addParameter(QgsProcessingParameterNumber(self.NUMBER,
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self.tr('Constant value'),
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QgsProcessingParameterNumber.Double,
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defaultValue=1))
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self.addParameter(QgsProcessingParameterRasterDestination(self.OUTPUT, self.tr('Constant')))
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def name(self):
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return 'createconstantrasterlayer'
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def displayName(self):
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return self.tr('Create constant raster layer')
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def processAlgorithm(self, parameters, context, feedback):
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crs = self.parameterAsCrs(parameters, self.TARGET_CRS, context)
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extent = self.parameterAsExtent(parameters, self.EXTENT, context, crs)
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value = self.parameterAsDouble(parameters, self.NUMBER, context)
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pixelSize = self.parameterAsDouble(parameters, self.PIXEL_SIZE, context)
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outputFile = self.parameterAsOutputLayer(parameters, self.OUTPUT, context)
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outputFormat = QgsRasterFileWriter.driverForExtension(os.path.splitext(outputFile)[1])
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rows = max([math.ceil(extent.height() / pixelSize), 1.0])
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cols = max([math.ceil(extent.width() / pixelSize), 1.0])
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writer = QgsRasterFileWriter(outputFile)
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writer.setOutputProviderKey('gdal')
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writer.setOutputFormat(outputFormat)
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provider = writer.createOneBandRaster(Qgis.Float32, cols, rows, extent, crs)
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if provider is None:
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raise QgsProcessingException(self.tr("Could not create raster output: {}").format(outputFile))
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if not provider.isValid():
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raise QgsProcessingException(self.tr("Could not create raster output {}: {}").format(outputFile,
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provider.error().message(
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QgsErrorMessage.Text)))
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provider.setNoDataValue(1, -9999)
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data = [value] * cols
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block = QgsRasterBlock(Qgis.Float32, cols, 1)
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block.setData(struct.pack('{}f'.format(len(data)), *data))
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total = 100.0 / rows if rows else 0
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for i in range(rows):
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if feedback.isCanceled():
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break
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provider.writeBlock(block, 1, 0, i)
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feedback.setProgress(int(i * rows))
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provider.setEditable(False)
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return {self.OUTPUT: outputFile}
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