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

# -*- coding: utf-8 -*-

"""
***************************************************************************
    BasicStatisticsNumbers.py
    ---------------------
    Date                 : September 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__ = 'September 2012'
__copyright__ = '(C) 2012, Victor Olaya'
# This will get replaced with a git SHA1 when you do a git archive
__revision__ = '$Format:%H$'

import math

from PyQt4.QtCore import *

from qgis.core import *

from sextante.core.GeoAlgorithm import GeoAlgorithm
from sextante.core.QGisLayers import QGisLayers

from sextante.parameters.ParameterVector import ParameterVector
from sextante.parameters.ParameterTableField import ParameterTableField

from sextante.outputs.OutputHTML import OutputHTML
from sextante.outputs.OutputNumber import OutputNumber

from sextante.algs.ftools import FToolsUtils as utils

class BasicStatisticsNumbers(GeoAlgorithm):

    INPUT_LAYER = "INPUT_LAYER"
    FIELD_NAME = "FIELD_NAME"
    OUTPUT_HTML_FILE = "OUTPUT_HTML_FILE"

    CV = "CV"
    MIN = "MIN"
    MAX = "MAX"
    SUM = "SUM"
    MEAN = "MEAN"
    COUNT = "COUNT"
    STD_DEV = "STD_DEV"
    RANGE = "RANGE"
    MEDIAN = "MEDIAN"
    UNIQUE = "UNIQUE"


    #===========================================================================
    # def getIcon(self):
    #    return QtGui.QIcon(os.path.dirname(__file__) + "/icons/basic_statistics.png")
    #===========================================================================

    def defineCharacteristics(self):
        self.name = "Basic statistics for numeric fields"
        self.group = "Vector table tools"

        self.addParameter(ParameterVector(self.INPUT_LAYER, "Input vector layer", ParameterVector.VECTOR_TYPE_ANY, False))
        self.addParameter(ParameterTableField(self.FIELD_NAME, "Field to calculate statistics on",
                                              self.INPUT_LAYER, ParameterTableField.DATA_TYPE_NUMBER))

        self.addOutput(OutputHTML(self.OUTPUT_HTML_FILE, "Statistics for numeric field"))

        self.addOutput(OutputNumber(self.CV, "Coefficient of Variation"))
        self.addOutput(OutputNumber(self.MIN, "Minimum value"))
        self.addOutput(OutputNumber(self.MAX, "Maximum value"))
        self.addOutput(OutputNumber(self.SUM, "Sum"))
        self.addOutput(OutputNumber(self.MEAN, "Mean value"))
        self.addOutput(OutputNumber(self.COUNT, "Count"))
        self.addOutput(OutputNumber(self.RANGE, "Range"))
        self.addOutput(OutputNumber(self.MEDIAN, "Median"))
        self.addOutput(OutputNumber(self.UNIQUE, "Number of unique values"))
        self.addOutput(OutputNumber(self.STD_DEV, "Standard deviation"))

    def processAlgorithm(self, progress):
        layer = QGisLayers.getObjectFromUri(self.getParameterValue(self.INPUT_LAYER))
        fieldName = self.getParameterValue(self.FIELD_NAME)

        outputFile = self.getOutputValue(self.OUTPUT_HTML_FILE)

        index = layer.fieldNameIndex(fieldName)

        cvValue = 0
        minValue = 0
        maxValue = 0
        sumValue = 0
        meanValue = 0
        medianValue = 0
        stdDevValue = 0

        isFirst = True
        values = []

        features = QGisLayers.features(layer)
        count = len(features)
        total = 100.0 / float(count)
        current = 0
        for ft in features:
            value = float(ft.attributes()[index])
            if isFirst:
                minValue = value
                maxValue = value
                isFirst = False
            else:
                if value < minValue:
                    minValue = value
                if value > maxValue:
                    maxValue = value

            values.append( value )
            sumValue += value

            current += 1
            progress.setPercentage(int(current * total))

        # calculate additional values
        rValue = maxValue - minValue
        uniqueValue = utils.getUniqueValuesCount(layer, index)

        if count > 0:
            meanValue = sumValue / count
            if meanValue != 0.00:
                for v in values:
                    stdDevValue += ((v - meanValue) * (v - meanValue))
                stdDevValue = math.sqrt(stdDevValue / count)
                cvValue = stdDevValue / meanValue

        if count > 1:
            tmp = values
            tmp.sort()
            # calculate median
            if (count % 2) == 0:
                medianValue = 0.5 * (tmp[(count - 1) / 2] + tmp[count / 2])
            else:
                medianValue = tmp[(count + 1) / 2 - 1]

        data = []
        data.append("Count: " + unicode(count))
        data.append("Unique values: " + unicode(uniqueValue))
        data.append("Minimum value: " + unicode(minValue))
        data.append("Maximum value: " + unicode(maxValue))
        data.append("Range: " + unicode(rValue))
        data.append("Sum: " + unicode(sumValue))
        data.append("Mean value: " + unicode(meanValue))
        data.append("Median value: " + unicode(medianValue))
        data.append("Standard deviation: " + unicode(stdDevValue))
        data.append("Coefficient of Variation: " + unicode(cvValue))

        self.createHTML(outputFile, data)

        self.setOutputValue(self.COUNT, count)
        self.setOutputValue(self.UNIQUE, uniqueValue)
        self.setOutputValue(self.MIN, minValue)
        self.setOutputValue(self.MAX, maxValue)
        self.setOutputValue(self.RANGE, rValue)
        self.setOutputValue(self.SUM, sumValue)
        self.setOutputValue(self.MEAN, meanValue)
        self.setOutputValue(self.MEDIAN, medianValue)
        self.setOutputValue(self.STD_DEV, stdDevValue)
        self.setOutputValue(self.CV, cvValue)

    def createHTML(self, outputFile, algData):
        f = open(outputFile, "w")
        for s in algData:
            f.write("<p>" + str(s) + "</p>")
        f.close()