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

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

"""
***************************************************************************
    EquivalentNumField.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,
                       QgsProcessingUtils)
from processing.algs.qgis import QgisAlgorithm
from processing.core.parameters import ParameterVector
from processing.core.parameters import ParameterTableField
from processing.core.outputs import OutputHTML

from processing.tools import vector


class VectorLayerScatterplot(QgisAlgorithm):

    INPUT = 'INPUT'
    OUTPUT = 'OUTPUT'
    XFIELD = 'XFIELD'
    YFIELD = 'YFIELD'

    def icon(self):
        return QgsApplication.getThemeIcon("/providerQgis.svg")

    def svgIconPath(self):
        return QgsApplication.iconPath("providerQgis.svg")

    def group(self):
        return self.tr('Graphics')

    def __init__(self):
        super().__init__()
        self.addParameter(ParameterVector(self.INPUT,
                                          self.tr('Input layer')))
        self.addParameter(ParameterTableField(self.XFIELD,
                                              self.tr('X attribute'),
                                              self.INPUT,
                                              ParameterTableField.DATA_TYPE_NUMBER))
        self.addParameter(ParameterTableField(self.YFIELD,
                                              self.tr('Y attribute'),
                                              self.INPUT,
                                              ParameterTableField.DATA_TYPE_NUMBER))

        self.addOutput(OutputHTML(self.OUTPUT, self.tr('Scatterplot')))

    def name(self):
        return 'vectorlayerscatterplot'

    def displayName(self):
        return self.tr('Vector layer scatterplot')

    def processAlgorithm(self, parameters, context, feedback):
        layer = QgsProcessingUtils.mapLayerFromString(self.getParameterValue(self.INPUT), context)
        xfieldname = self.getParameterValue(self.XFIELD)
        yfieldname = self.getParameterValue(self.YFIELD)

        output = self.getOutputValue(self.OUTPUT)

        values = vector.values(layer, xfieldname, yfieldname)
        data = [go.Scatter(x=values[xfieldname],
                           y=values[yfieldname],
                           mode='markers')]
        plt.offline.plot(data, filename=output, auto_open=False)