QGIS/python/plugins/processing/algs/qgis/RasterCalculator.py
2018-09-04 15:46:42 +02:00

287 lines
13 KiB
Python

# -*- coding: utf-8 -*-
"""
***************************************************************************
RasterLayerCalculator.py
---------------------
Date : November 2016
Copyright : (C) 2016 by Victor Olaya
Email : volayaf at gmail dot com
***************************************************************************
* *
* This program is free software; you can redistribute it and/or modify *
* it under the terms of the GNU General Public License as published by *
* the Free Software Foundation; either version 2 of the License, or *
* (at your option) any later version. *
* *
***************************************************************************
"""
__author__ = 'Victor Olaya'
__date__ = 'November 2016'
__copyright__ = '(C) 2016, Victor Olaya'
# This will get replaced with a git SHA1 when you do a git archive
__revision__ = '$Format:%H$'
import os
import math
from processing.algs.qgis.QgisAlgorithm import QgisAlgorithm
from processing.algs.gdal.GdalUtils import GdalUtils
from qgis.core import (QgsProcessing,
QgsProcessingException,
QgsProcessingUtils,
QgsProcessingParameterCrs,
QgsProcessingParameterMultipleLayers,
QgsProcessingParameterNumber,
QgsProcessingParameterExtent,
QgsProcessingParameterRasterDestination,
QgsProcessingParameterRasterLayer,
QgsProcessingOutputRasterLayer,
QgsProcessingParameterString,
QgsCoordinateTransform,
QgsMapLayer)
from qgis.PyQt.QtCore import QObject
from qgis.analysis import QgsRasterCalculator, QgsRasterCalculatorEntry
class RasterCalculator(QgisAlgorithm):
LAYERS = 'LAYERS'
EXTENT = 'EXTENT'
CELLSIZE = 'CELLSIZE'
EXPRESSION = 'EXPRESSION'
CRS = 'CRS'
OUTPUT = 'OUTPUT'
def group(self):
return self.tr('Raster analysis')
def groupId(self):
return 'rasteranalysis'
def __init__(self):
super().__init__()
def initAlgorithm(self, config=None):
class ParameterRasterCalculatorExpression(QgsProcessingParameterString):
def __init__(self, name='', description='', multiLine=False):
super().__init__(name, description, multiLine=multiLine)
self.setMetadata({
'widget_wrapper': 'processing.algs.qgis.ui.RasterCalculatorWidgets.ExpressionWidgetWrapper'
})
def type(self):
return 'raster_calc_expression'
def clone(self):
return ParameterRasterCalculatorExpression(self.name(), self.description(), self.multiLine())
self.addParameter(ParameterRasterCalculatorExpression(self.EXPRESSION, self.tr('Expression'),
multiLine=True))
self.addParameter(QgsProcessingParameterMultipleLayers(self.LAYERS,
self.tr('Reference layer(s) (used for automated extent, cellsize, and CRS)'),
layerType=QgsProcessing.TypeRaster,
optional=True))
self.addParameter(QgsProcessingParameterNumber(self.CELLSIZE,
self.tr('Cell size (use 0 or empty to set it automatically)'),
type=QgsProcessingParameterNumber.Double,
minValue=0.0, defaultValue=0.0, optional=True))
self.addParameter(QgsProcessingParameterExtent(self.EXTENT,
self.tr('Output extent'),
optional=True))
self.addParameter(QgsProcessingParameterCrs(self.CRS, 'Output CRS', optional=True))
self.addParameter(QgsProcessingParameterRasterDestination(self.OUTPUT, self.tr('Output')))
def name(self):
return 'rastercalculator'
def displayName(self):
return self.tr('Raster calculator')
def processAlgorithm(self, parameters, context, feedback):
expression = self.parameterAsString(parameters, self.EXPRESSION, context)
layers = self.parameterAsLayerList(parameters, self.LAYERS, context)
layersDict = {}
if layers:
layersDict = {lyr.source(): lyr for lyr in layers}
crs = self.parameterAsCrs(parameters, self.CRS, context)
if crs is None or not crs.isValid():
if not layers:
raise QgsProcessingException(self.tr("No reference layer selected nor CRS provided"))
else:
crs = list(layersDict.values())[0].crs()
bbox = self.parameterAsExtent(parameters, self.EXTENT, context)
if bbox.isNull() and not layers:
raise QgsProcessingException(self.tr("No reference layer selected nor extent box provided"))
if not bbox.isNull():
bboxCrs = self.parameterAsExtentCrs(parameters, self.EXTENT, context)
if bboxCrs != crs:
transform = QgsCoordinateTransform(bboxCrs, crs, context.project())
bbox = transform.transformBoundingBox(bbox)
if bbox.isNull() and layers:
bbox = QgsProcessingUtils.combineLayerExtents(layers, crs)
cellsize = self.parameterAsDouble(parameters, self.CELLSIZE, context)
if cellsize == 0 and not layers:
raise QgsProcessingException(self.tr("No reference layer selected nor cellsize value provided"))
def _cellsize(layer):
ext = layer.extent()
if layer.crs() != crs:
transform = QgsCoordinateTransform(layer.crs(), crs, context.project())
ext = transform.transformBoundingBox(ext)
return (ext.xMaximum() - ext.xMinimum()) / layer.width()
if cellsize == 0:
cellsize = min([_cellsize(lyr) for lyr in layersDict.values()])
# check for layers available in the model
layersDictCopy = layersDict.copy() # need a shallow copy because next calls invalidate iterator
for lyr in layersDictCopy.values():
expression = self.mappedNameToLayer(lyr, expression, layersDict, context)
# check for layers available in the project
for lyr in QgsProcessingUtils.compatibleRasterLayers(context.project()):
expression = self.mappedNameToLayer(lyr, expression, layersDict, context)
# create the list of layers to be passed as inputs to RasterCalculaltor
# at this phase expression has been modified to match available layers
# in the current scope
entries = []
for name, lyr in layersDict.items():
for n in range(lyr.bandCount()):
ref = '{:s}@{:d}'.format(name, n + 1)
if ref in expression:
entry = QgsRasterCalculatorEntry()
entry.ref = ref
entry.raster = lyr
entry.bandNumber = n + 1
entries.append(entry)
output = self.parameterAsOutputLayer(parameters, self.OUTPUT, context)
width = math.floor((bbox.xMaximum() - bbox.xMinimum()) / cellsize)
height = math.floor((bbox.yMaximum() - bbox.yMinimum()) / cellsize)
driverName = GdalUtils.getFormatShortNameFromFilename(output)
calc = QgsRasterCalculator(expression,
output,
driverName,
bbox,
crs,
width,
height,
entries)
res = calc.processCalculation(feedback)
if res == QgsRasterCalculator.ParserError:
raise QgsProcessingException(self.tr("Error parsing formula"))
return {self.OUTPUT: output}
def processBeforeAddingToModeler(self, algorithm, model):
values = []
expression = algorithm.params[self.EXPRESSION]
for i in list(model.inputs.values()):
param = i.param
if isinstance(param, QgsProcessingParameterRasterLayer) and "{}@".format(param.name) in expression:
values.append(ValueFromInput(param.name()))
if algorithm.name:
dependent = model.getDependentAlgorithms(algorithm.name)
else:
dependent = []
for alg in list(model.algs.values()):
if alg.modeler_name not in dependent:
for out in alg.algorithm.outputs:
if (isinstance(out, QgsProcessingOutputRasterLayer) and
"{}:{}@".format(alg.modeler_name, out.name) in expression):
values.append(ValueFromOutput(alg.modeler_name, out.name))
algorithm.params[self.LAYERS] = values
def mappedNameToLayer(self, lyr, expression, layersDict, context):
'''Try to identify if a real layer is mapped in the expression with a symbolic name.'''
nameToMap = lyr.source()
# check if nameToMap is a file
# TODO: what about URI eg for a COG?
if os.path.isfile(nameToMap):
# get only the name without extension and path of the file
nameToMap = os.path.splitext(os.path.basename(nameToMap))[0]
# check for layers directly added in the expression
if (nameToMap + "@") in expression:
layersDict[nameToMap] = lyr
# get "algorithm_inputs" scope of the expressionContext related
# with mapped variables
indexOfScope = context.expressionContext().indexOfScope("algorithm_inputs")
if indexOfScope >= 0:
expContextAlgInputsScope = context.expressionContext().scope(indexOfScope)
# check for the layers that are mapped as input in a model
# to do this check in the latest scope all passed variables
# to look for a variable that is a layer or a string filename ç
# to a layer
varDescription = None
for varName in expContextAlgInputsScope.variableNames():
layerInContext = expContextAlgInputsScope.variable(varName)
if not isinstance(layerInContext, str) and not isinstance(layerInContext, QgsMapLayer):
continue
if isinstance(layerInContext, QgsMapLayer) and nameToMap not in layerInContext.source():
continue
varDescription = expContextAlgInputsScope.description(varName)
# because there can be variable with None or "" description
# then skip them
if not varDescription:
continue
# check if it's description starts with Output as in:
# Output 'Output' from algorithm 'calc1'
# as set in https://github.com/qgis/QGIS/blob/master/src/core/processing/models/qgsprocessingmodelalgorithm.cpp#L516
# but var in expression is called simply
# 'Output' from algorithm 'calc1'
# get the translatin string to use to parse the description
# HAVE to use the same translated string as in
# https://github.com/qgis/QGIS/blob/master/src/core/processing/models/qgsprocessingmodelalgorithm.cpp#L516
translatedDesc = self.tr("Output '%1' from algorithm '%2'")
elementZero = translatedDesc.split(" ")[0] # For english the string result should be "Output"
elements = varDescription.split(" ")
if len(elements) > 1 and elements[0] == elementZero:
# remove heading QObject.tr"Output ") string. Note adding a space at the end of elementZero!
varDescription = varDescription[len(elementZero) + 1:]
# check if cleaned varDescription is present in the expression
# if not skip it
if (varDescription + "@") not in expression:
continue
# !!!found!!! => substitute in expression
# and add in the list of layers that will be passed to raster calculator
nameToMap = varName
new = "{}@".format(nameToMap)
old = "{}@".format(varDescription)
expression = expression.replace(old, new)
layersDict[nameToMap] = lyr
# need return the modified expression because it's not a reference
return expression