QGIS/python/plugins/processing/algs/qgis/RandomSelection.py

138 lines
4.4 KiB
Python

"""
***************************************************************************
RandomSelection.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. *
* *
***************************************************************************
"""
__author__ = "Victor Olaya"
__date__ = "August 2012"
__copyright__ = "(C) 2012, Victor Olaya"
import os
import random
from qgis.PyQt.QtGui import QIcon
from qgis.core import (
QgsApplication,
QgsFeatureSink,
QgsProcessingException,
QgsProcessingUtils,
QgsProcessingAlgorithm,
QgsProcessingParameterVectorLayer,
QgsProcessingParameterEnum,
QgsProcessingParameterNumber,
QgsProcessingParameterFeatureSink,
QgsProcessingOutputVectorLayer,
)
from processing.algs.qgis.QgisAlgorithm import QgisAlgorithm
pluginPath = os.path.split(os.path.split(os.path.dirname(__file__))[0])[0]
class RandomSelection(QgisAlgorithm):
INPUT = "INPUT"
OUTPUT = "OUTPUT"
METHOD = "METHOD"
NUMBER = "NUMBER"
def icon(self):
return QgsApplication.getThemeIcon("/algorithms/mAlgorithmSelectRandom.svg")
def svgIconPath(self):
return QgsApplication.iconPath("/algorithms/mAlgorithmSelectRandom.svg")
def group(self):
return self.tr("Vector selection")
def groupId(self):
return "vectorselection"
def flags(self):
return (
super().flags()
| QgsProcessingAlgorithm.Flag.FlagNoThreading
| QgsProcessingAlgorithm.Flag.FlagNotAvailableInStandaloneTool
)
def __init__(self):
super().__init__()
def initAlgorithm(self, config=None):
self.methods = [
self.tr("Number of selected features"),
self.tr("Percentage of selected features"),
]
self.addParameter(
QgsProcessingParameterVectorLayer(self.INPUT, self.tr("Input layer"))
)
self.addParameter(
QgsProcessingParameterEnum(
self.METHOD, self.tr("Method"), self.methods, False, 0
)
)
self.addParameter(
QgsProcessingParameterNumber(
self.NUMBER,
self.tr("Number/percentage of selected features"),
QgsProcessingParameterNumber.Type.Integer,
10,
False,
0.0,
)
)
self.addOutput(
QgsProcessingOutputVectorLayer(self.OUTPUT, self.tr("Selected (random)"))
)
def name(self):
return "randomselection"
def displayName(self):
return self.tr("Random selection")
def shortDescription(self):
return self.tr("Takes a vector layer and randomly selects features.")
def processAlgorithm(self, parameters, context, feedback):
layer = self.parameterAsVectorLayer(parameters, self.INPUT, context)
method = self.parameterAsEnum(parameters, self.METHOD, context)
ids = layer.allFeatureIds()
value = self.parameterAsInt(parameters, self.NUMBER, context)
if method == 0:
if value > len(ids):
raise QgsProcessingException(
self.tr(
"Selected number is greater than feature count. "
"Choose a lower value and try again."
)
)
else:
if value > 100:
raise QgsProcessingException(
self.tr(
"Percentage can't be greater than 100. Set a "
"different value and try again."
)
)
value = int(round(value / 100.0, 4) * len(ids))
selran = random.sample(ids, value)
layer.selectByIds(selran)
return {self.OUTPUT: parameters[self.INPUT]}