QGIS/python/plugins/sextante/algs/ftools/RandomSelection.py

90 lines
3.5 KiB
Python

# -*- coding: utf-8 -*-
"""
***************************************************************************
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'
# This will get replaced with a git SHA1 when you do a git archive
__revision__ = '$Format:%H$'
import os.path
import random
from PyQt4 import QtGui
from PyQt4.QtCore import *
from qgis.core import *
from sextante.core.GeoAlgorithm import GeoAlgorithm
from sextante.core.GeoAlgorithmExecutionException import GeoAlgorithmExecutionException
from sextante.core.QGisLayers import QGisLayers
from sextante.parameters.ParameterSelection import ParameterSelection
from sextante.parameters.ParameterVector import ParameterVector
from sextante.parameters.ParameterNumber import ParameterNumber
from sextante.outputs.OutputVector import OutputVector
class RandomSelection(GeoAlgorithm):
INPUT = "INPUT"
OUTPUT = "OUTPUT"
METHOD = "METHOD"
NUMBER = "NUMBER"
METHODS = ["Number of selected features",
"Percentage of selected features"
]
#===========================================================================
# def getIcon(self):
# return QtGui.QIcon(os.path.dirname(__file__) + "/icons/random_selection.png")
#===========================================================================
def defineCharacteristics(self):
self.name = "Random selection"
self.group = "Vector selection tools"
self.addParameter(ParameterVector(self.INPUT, "Input layer", ParameterVector.VECTOR_TYPE_ANY))
self.addParameter(ParameterSelection(self.METHOD, "Method", self.METHODS, 0))
self.addParameter(ParameterNumber(self.NUMBER, "Number/persentage of selected features", 1, None, 10))
self.addOutput(OutputVector(self.OUTPUT, "Selection", True))
def processAlgorithm(self, progress):
filename = self.getParameterValue(self.INPUT)
layer = QGisLayers.getObjectFromUri(filename)
method = self.getParameterValue(self.METHOD)
featureCount = layer.featureCount()
value = int(self.getParameterValue(self.NUMBER))
if method == 0:
if value > featureCount:
raise GeoAlgorithmExecutionException("Selected number is greater that feature count. Choose lesser value and try again.")
else:
if value > 100:
raise GeoAlgorithmExecutionException("Persentage can't be greater than 100. Set corrent value and try again.")
value = int(round((value / 100.0000), 4) * featureCount)
selran = random.sample(xrange(0, featureCount), value)
layer.setSelectedFeatures(selran)
self.setOutputValue(self.OUTPUT, filename)