示例#1
0
 def processAlgorithm(self, progress):
     uri = self.getParameterValue(self.INPUT)
     layer = QGisLayers.getObjectFromUri(uri)
     outputplot = self.getOutputValue(self.PLOT)
     outputtable = self.getOutputFromName(self.TABLE)
     values = raster.scanraster(layer, progress)
     nbins = self.getParameterValue(self.BINS)
     #ALERT:this is potentially blocking if the layer is too big
     plt.close()
     valueslist = []
     for v in values:
         if v is not None:
             valueslist.append(v)
     n, bins, values = plt.hist(valueslist, nbins)
     fields = [
         QgsField("CENTER_VALUE", QVariant.Double),
         QgsField("NUM_ELEM", QVariant.Double)
     ]
     writer = outputtable.getTableWriter(fields)
     for i in xrange(len(values)):
         writer.addRecord([str(bins[i]) + "-" + str(bins[i + 1]), n[i]])
     plotFilename = outputplot + ".png"
     lab.savefig(plotFilename)
     f = open(outputplot, "w")
     f.write("<img src=\"" + plotFilename + "\"/>")
     f.close()
    def processAlgorithm(self, progress):
        outputFile = self.getOutputValue(self.OUTPUT_HTML_FILE)
        uri = self.getParameterValue(self.INPUT)
        layer = QGisLayers.getObjectFromUri(uri)
        values = raster.scanraster(layer, progress)

        n = 0
        nodata = 0
        mean = 0
        M2 = 0
        sum = 0
        minvalue = None
        maxvalue = None

        for v in values:
            if v is not None:
                sum += v
                n = n + 1
                delta = v - mean
                mean = mean + delta/n
                M2 = M2 + delta*(v - mean)
                if minvalue is None:
                    minvalue = v
                    maxvalue = v
                else:
                    minvalue = min(v, minvalue)
                    maxvalue = max(v, maxvalue)
            else:
                nodata += 1

        variance = M2/(n - 1)
        stddev = math.sqrt(variance)

        data = []
        data.append("Valid cells: " + unicode(n))
        data.append("No-data cells: " + unicode(nodata))
        data.append("Minimum value: " + unicode(minvalue))
        data.append("Maximum value: " + unicode(maxvalue))
        data.append("Sum: " + unicode(sum))
        data.append("Mean value: " + unicode(mean))
        data.append("Standard deviation: " + unicode(stddev))

        self.createHTML(outputFile, data)

        self.setOutputValue(self.COUNT, n)
        self.setOutputValue(self.NO_DATA_COUNT, nodata)
        self.setOutputValue(self.MIN, minvalue)
        self.setOutputValue(self.MAX, maxvalue)
        self.setOutputValue(self.SUM, sum)
        self.setOutputValue(self.MEAN, mean)
        self.setOutputValue(self.STD_DEV, stddev)
 def processAlgorithm(self, progress):
     uri = self.getParameterValue(self.INPUT)
     layer = QGisLayers.getObjectFromUri(uri)
     outputplot = self.getOutputValue(self.PLOT)
     outputtable = self.getOutputFromName(self.TABLE)
     values = raster.scanraster(layer, progress)
     nbins = self.getParameterValue(self.BINS)
     #ALERT:this is potentially blocking if the layer is too big
     plt.close()
     valueslist = []
     for v in values:
         if v is not None:
             valueslist.append(v)
     n, bins, values = plt.hist(valueslist, nbins)
     fields = [QgsField("CENTER_VALUE", QVariant.Double), QgsField("NUM_ELEM", QVariant.Double)]
     writer = outputtable.getTableWriter(fields)
     for i in xrange(len(values)):
         writer.addRecord([str(bins[i]) + "-" + str(bins[i+1]) , n[i]])
     plotFilename = outputplot +".png"
     lab.savefig(plotFilename)
     f = open(outputplot, "w")
     f.write("<img src=\"" + plotFilename + "\"/>")
     f.close()