2017-06-06 13:41:42 +10:00

151 lines
5.6 KiB
Python

# -*- coding: utf-8 -*-
"""
***************************************************************************
MeanCoords.py
---------------------
Date : August 2012
Copyright : (C) 2012 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. *
* *
***************************************************************************
"""
from builtins import str
__author__ = 'Victor Olaya'
__date__ = 'August 2012'
__copyright__ = '(C) 2012, Victor Olaya'
# 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.PyQt.QtCore import QVariant
from qgis.core import QgsField, QgsFeature, QgsGeometry, QgsPointXY, QgsWkbTypes, QgsProcessingUtils, QgsFields
from processing.algs.qgis.QgisAlgorithm import QgisAlgorithm
from processing.core.GeoAlgorithmExecutionException import GeoAlgorithmExecutionException
from processing.core.parameters import ParameterTableField
from processing.core.parameters import ParameterVector
from processing.core.outputs import OutputVector
from processing.tools import dataobjects, vector
pluginPath = os.path.split(os.path.split(os.path.dirname(__file__))[0])[0]
class MeanCoords(QgisAlgorithm):
POINTS = 'POINTS'
WEIGHT = 'WEIGHT'
OUTPUT = 'OUTPUT'
UID = 'UID'
WEIGHT = 'WEIGHT'
def icon(self):
return QIcon(os.path.join(pluginPath, 'images', 'ftools', 'mean.png'))
def group(self):
return self.tr('Vector analysis tools')
def __init__(self):
super().__init__()
self.addParameter(ParameterVector(self.POINTS,
self.tr('Input layer')))
self.addParameter(ParameterTableField(self.WEIGHT,
self.tr('Weight field'),
MeanCoords.POINTS,
ParameterTableField.DATA_TYPE_NUMBER,
optional=True))
self.addParameter(ParameterTableField(self.UID,
self.tr('Unique ID field'),
MeanCoords.POINTS,
optional=True))
self.addOutput(OutputVector(MeanCoords.OUTPUT, self.tr('Mean coordinates'), datatype=[dataobjects.TYPE_VECTOR_POINT]))
def name(self):
return 'meancoordinates'
def displayName(self):
return self.tr('Mean coordinate(s)')
def processAlgorithm(self, parameters, context, feedback):
layer = QgsProcessingUtils.mapLayerFromString(self.getParameterValue(self.POINTS), context)
weightField = self.getParameterValue(self.WEIGHT)
uniqueField = self.getParameterValue(self.UID)
if weightField is None:
weightIndex = -1
else:
weightIndex = layer.fields().lookupField(weightField)
if uniqueField is None:
uniqueIndex = -1
else:
uniqueIndex = layer.fields().lookupField(uniqueField)
fieldList = QgsFields()
fieldList.append(QgsField('MEAN_X', QVariant.Double, '', 24, 15))
fieldList.append(QgsField('MEAN_Y', QVariant.Double, '', 24, 15))
fieldList.append(QgsField('UID', QVariant.String, '', 255))
writer = self.getOutputFromName(self.OUTPUT).getVectorWriter(fieldList, QgsWkbTypes.Point, layer.crs(), context)
features = QgsProcessingUtils.getFeatures(layer, context)
total = 100.0 / QgsProcessingUtils.featureCount(layer, context)
means = {}
for current, feat in enumerate(features):
feedback.setProgress(int(current * total))
if uniqueIndex == -1:
clazz = "Single class"
else:
clazz = str(feat.attributes()[uniqueIndex]).strip()
if weightIndex == -1:
weight = 1.00
else:
try:
weight = float(feat.attributes()[weightIndex])
except:
weight = 1.00
if weight < 0:
raise GeoAlgorithmExecutionException(self.tr('Negative weight value found. Please fix your data and try again.'))
if clazz not in means:
means[clazz] = (0, 0, 0)
(cx, cy, totalweight) = means[clazz]
geom = QgsGeometry(feat.geometry())
geom = vector.extractPoints(geom)
for i in geom:
cx += i.x() * weight
cy += i.y() * weight
totalweight += weight
means[clazz] = (cx, cy, totalweight)
current = 0
total = 100.0 / len(means)
for (clazz, values) in list(means.items()):
outFeat = QgsFeature()
cx = values[0] / values[2]
cy = values[1] / values[2]
meanPoint = QgsPointXY(cx, cy)
outFeat.setGeometry(QgsGeometry.fromPoint(meanPoint))
outFeat.setAttributes([cx, cy, clazz])
writer.addFeature(outFeat)
current += 1
feedback.setProgress(int(current * total))
del writer