QGIS/python/plugins/processing/algs/qgis/IdwInterpolation.py
Nyall Dawson 1e13d733c2 Move declaration of algorithm parameters/outputs to a new virtual
initAlgorithm() method

This allows 2 benefits:
- algorithms can be subclassed and have subclasses add additional
parameters/outputs to the algorithm. With the previous approach
of declaring parameters/outputs in the constructor, it's not
possible to call virtual methods to add additional parameters/
outputs (since you can't call virtual methods from a constructor).

- initAlgorithm takes a variant map argument, allowing the algorithm
to dynamically adjust its declared parameters and outputs according
to this configuration map. This potentially allows model algorithms which
can be configured to have variable numbers of parameters and
outputs at run time. E.g. a "router" algorithm which directs
features to one of any number of output sinks depending on some
user configured criteria.
2017-07-10 16:31:14 +10:00

204 lines
8.1 KiB
Python

# -*- coding: utf-8 -*-
"""
***************************************************************************
IdwInterpolation.py
---------------------
Date : October 2016
Copyright : (C) 2016 by Alexander Bruy
Email : alexander dot bruy 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__ = 'Alexander Bruy'
__date__ = 'October 2016'
__copyright__ = '(C) 2016, Alexander Bruy'
# This will get replaced with a git SHA1 when you do a git archive
__revision__ = '$Format:%H$'
import os
from qgis.PyQt.QtGui import QIcon
from qgis.core import (QgsRectangle,
QgsProcessingUtils,
QgsProcessingParameterDefinition)
from qgis.analysis import (QgsInterpolator,
QgsIDWInterpolator,
QgsGridFileWriter
)
from processing.algs.qgis.QgisAlgorithm import QgisAlgorithm
from processing.core.GeoAlgorithmExecutionException import GeoAlgorithmExecutionException
from processing.core.parameters import (Parameter,
ParameterNumber,
ParameterExtent,
_splitParameterOptions)
from processing.core.outputs import OutputRaster
pluginPath = os.path.split(os.path.split(os.path.dirname(__file__))[0])[0]
class IdwInterpolation(QgisAlgorithm):
INTERPOLATION_DATA = 'INTERPOLATION_DATA'
DISTANCE_COEFFICIENT = 'DISTANCE_COEFFICIENT'
COLUMNS = 'COLUMNS'
ROWS = 'ROWS'
CELLSIZE_X = 'CELLSIZE_X'
CELLSIZE_Y = 'CELLSIZE_Y'
EXTENT = 'EXTENT'
OUTPUT_LAYER = 'OUTPUT_LAYER'
def icon(self):
return QIcon(os.path.join(pluginPath, 'images', 'interpolation.png'))
def group(self):
return self.tr('Interpolation')
def __init__(self):
super().__init__()
def initAlgorithm(self, config=None):
class ParameterInterpolationData(Parameter):
default_metadata = {
'widget_wrapper': 'processing.algs.qgis.ui.InterpolationDataWidget.InterpolationDataWidgetWrapper'
}
def __init__(self, name='', description=''):
Parameter.__init__(self, name, description)
def setValue(self, value):
if value is None:
if not self.flags() & QgsProcessingParameterDefinition.FlagOptional:
return False
self.value = None
return True
if value == '':
if not self.flags() & QgsProcessingParameterDefinition.FlagOptional:
return False
if isinstance(value, str):
self.value = value if value != '' else None
else:
self.value = ParameterInterpolationData.dataToString(value)
return True
def getValueAsCommandLineParameter(self):
return '"{}"'.format(self.value)
def getAsScriptCode(self):
param_type = ''
param_type += 'interpolation data '
return '##' + self.name + '=' + param_type
@classmethod
def fromScriptCode(self, line):
isOptional, name, definition = _splitParameterOptions(line)
descName = QgsProcessingParameters.descriptionFromName(name)
parent = definition.lower().strip()[len('interpolation data') + 1:]
return ParameterInterpolationData(name, descName, parent)
@staticmethod
def dataToString(data):
s = ''
for c in data:
s += '{}, {}, {:d}, {:d};'.format(c[0],
c[1],
c[2],
c[3])
return s[:-1]
self.addParameter(ParameterInterpolationData(self.INTERPOLATION_DATA,
self.tr('Input layer(s)')))
self.addParameter(ParameterNumber(self.DISTANCE_COEFFICIENT,
self.tr('Distance coefficient P'),
0.0, 99.99, 2.0))
self.addParameter(ParameterNumber(self.COLUMNS,
self.tr('Number of columns'),
0, 10000000, 300))
self.addParameter(ParameterNumber(self.ROWS,
self.tr('Number of rows'),
0, 10000000, 300))
self.addParameter(ParameterNumber(self.CELLSIZE_X,
self.tr('Cell Size X'),
0.0, 999999.000000, 0.0))
self.addParameter(ParameterNumber(self.CELLSIZE_Y,
self.tr('Cell Size Y'),
0.0, 999999.000000, 0.0))
self.addParameter(ParameterExtent(self.EXTENT,
self.tr('Extent'),
optional=False))
self.addOutput(OutputRaster(self.OUTPUT_LAYER,
self.tr('Interpolated')))
def name(self):
return 'idwinterpolation'
def displayName(self):
return self.tr('IDW interpolation')
def processAlgorithm(self, parameters, context, feedback):
interpolationData = self.getParameterValue(self.INTERPOLATION_DATA)
coefficient = self.getParameterValue(self.DISTANCE_COEFFICIENT)
columns = self.getParameterValue(self.COLUMNS)
rows = self.getParameterValue(self.ROWS)
cellsizeX = self.getParameterValue(self.CELLSIZE_X)
cellsizeY = self.getParameterValue(self.CELLSIZE_Y)
extent = self.getParameterValue(self.EXTENT).split(',')
output = self.getOutputValue(self.OUTPUT_LAYER)
if interpolationData is None:
raise GeoAlgorithmExecutionException(
self.tr('You need to specify at least one input layer.'))
xMin = float(extent[0])
xMax = float(extent[1])
yMin = float(extent[2])
yMax = float(extent[3])
bbox = QgsRectangle(xMin, yMin, xMax, yMax)
layerData = []
layers = []
for row in interpolationData.split(';'):
v = row.split(',')
data = QgsInterpolator.LayerData()
# need to keep a reference until interpolation is complete
layer = QgsProcessingUtils.mapLayerFromString(v[0], context)
data.vectorLayer = layer
layers.append(layer)
data.zCoordInterpolation = bool(v[1])
data.interpolationAttribute = int(v[2])
if v[3] == '0':
data.mInputType = QgsInterpolator.POINTS
elif v[3] == '1':
data.mInputType = QgsInterpolator.STRUCTURE_LINES
else:
data.mInputType = QgsInterpolator.BREAK_LINES
layerData.append(data)
interpolator = QgsIDWInterpolator(layerData)
interpolator.setDistanceCoefficient(coefficient)
writer = QgsGridFileWriter(interpolator,
output,
bbox,
columns,
rows,
cellsizeX,
cellsizeY)
writer.writeFile()