QGIS/python/plugins/processing/algs/qgis/RasterLayerHistogram.py

86 lines
2.9 KiB
Python

# -*- coding: utf-8 -*-
"""
***************************************************************************
RasterLayerHistogram.py
---------------------
Date : January 2013
Copyright : (C) 2013 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__ = 'January 2013'
__copyright__ = '(C) 2013, Victor Olaya'
# This will get replaced with a git SHA1 when you do a git archive
__revision__ = '$Format:%H$'
import plotly as plt
import plotly.graph_objs as go
from qgis.core import (QgsApplication)
from processing.core.GeoAlgorithm import GeoAlgorithm
from processing.core.parameters import ParameterNumber
from processing.core.parameters import ParameterRaster
from processing.core.outputs import OutputHTML
from processing.tools import dataobjects, raster
class RasterLayerHistogram(GeoAlgorithm):
INPUT = 'INPUT'
BINS = 'BINS'
PLOT = 'PLOT'
def icon(self):
return QgsApplication.getThemeIcon("/providerQgis.svg")
def svgIconPath(self):
return QgsApplication.iconPath("providerQgis.svg")
def group(self):
return self.tr('Graphics')
def name(self):
return 'rasterlayerhistogram'
def displayName(self):
return self.tr('Raster layer histogram')
def defineCharacteristics(self):
self.addParameter(ParameterRaster(self.INPUT,
self.tr('Input layer')))
self.addParameter(ParameterNumber(self.BINS,
self.tr('Number of bins'), 2, None, 10))
self.addOutput(OutputHTML(self.PLOT, self.tr('Histogram')))
def processAlgorithm(self, context, feedback):
layer = dataobjects.getLayerFromString(
self.getParameterValue(self.INPUT))
nbins = self.getParameterValue(self.BINS)
output = self.getOutputValue(self.PLOT)
# ALERT: this is potentially blocking if the layer is too big
values = raster.scanraster(layer, feedback)
valueslist = []
for v in values:
if v is not None:
valueslist.append(v)
data = [go.Histogram(x=valueslist,
nbinsx=nbins)]
plt.offline.plot(data, filename=output, auto_open=False)