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()