refactor basic statistics tool

Author: alexbruy

python/plugins/sextante/ftools/BasicStatistics.py

@@ -0,0 +1,186 @@
+import os.path
+import math
+
+from PyQt4 import QtGui
+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.parameters.ParameterBoolean import ParameterBoolean
+
+from sextante.outputs.OutputHTML import OutputHTML
+from sextante.outputs.OutputNumber import OutputNumber
+
+from sextante.ftools import FToolsUtils as utils
+
+class BasicStatisticsNumbers(GeoAlgorithm):
+
+    INPUT_LAYER = "INPUT_LAYER"
+    FIELD_NAME = "FIELD_NAME"
+    USE_SELECTION = "USE_SELECTION"
+    OUTPUT_HTML_FILE = "OUTPUT_HTML_FILE"
+
+    CV = "CV"
+    MIN = "MIN"
+    MAX = "MAX"
+    SUM = "SUM"
+    MEAN = "MEAN"
+    COUNT = "COUNT"
+    RANGE = "RANGE"
+    MEDIAN = "MEDIAN"
+    UNIQUE = "UNIQUE"
+    STD_DEV = "STD_DEV"
+
+    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 = "Analysis 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.addParameter(ParameterBoolean(self.USE_SELECTION, "Use selection", False))
+
+        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)
+        useSelection = self.getParameterValue(self.USE_SELECTION)
+
+        outputFile = self.getOutputValue(self.OUTPUT_HTML_FILE)
+
+        index = layer.fieldNameIndex(fieldName)
+        layer.select([index], QgsRectangle(), False)
+
+        count = 0
+        rValue = 0
+        cvValue = 0
+        minValue = 0
+        maxValue = 0
+        sumValue = 0
+        meanValue = 0
+        medianValue = 0
+        stdDevValue = 0
+        uniqueValue = 0
+
+        isFirst = True
+        values = []
+
+        if useSelection:
+            selection = layer.selectedFeatures()
+            count = layer.selectedFeatureCount()
+            total = 100.0 / float(count)
+            current = 0
+
+            for f in selection:
+                value = float(f.attributeMap()[index].toDouble()[0])
+
+                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))
+        else:
+            count = layer.featureCount()
+            total = 100.0 / float(count)
+            current = 0
+
+            ft = QgsFeature()
+            while layer.nextFeature(ft):
+                value = float(ft.attributeMap()[index].toDouble()[0])
+
+                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, useSelection)
+
+        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()