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

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

"""
***************************************************************************
    ExportGeometryInfo.py
    ---------------------
    Date                 : August 2012
    Copyright            : (C) 2012 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__ = 'August 2012'
__copyright__ = '(C) 2012, Victor Olaya'

# This will get replaced with a git SHA1 when you do a git archive

__revision__ = '$Format:%H$'

import os

from qgis.PyQt.QtGui import QIcon
from qgis.PyQt.QtCore import QVariant

from qgis.core import (QgsCoordinateTransform,
                       QgsField,
                       QgsFields,
                       QgsWkbTypes,
                       QgsFeatureSink,
                       QgsDistanceArea,
                       QgsProcessingUtils,
                       QgsProcessingParameterFeatureSource,
                       QgsProcessingParameterEnum,
                       QgsProcessingParameterFeatureSink)

from processing.algs.qgis.QgisAlgorithm import QgisAlgorithm
from processing.tools import vector

pluginPath = os.path.split(os.path.split(os.path.dirname(__file__))[0])[0]


class ExportGeometryInfo(QgisAlgorithm):

    INPUT = 'INPUT'
    METHOD = 'CALC_METHOD'
    OUTPUT = 'OUTPUT'

    def icon(self):
        return QIcon(os.path.join(pluginPath, 'images', 'ftools', 'export_geometry.png'))

    def tags(self):
        return self.tr('export,add,information,measurements,areas,lengths,perimeters,latitudes,longitudes,x,y,z,extract,points,lines,polygons').split(',')

    def group(self):
        return self.tr('Vector geometry')

    def __init__(self):
        super().__init__()
        self.export_z = False
        self.export_m = False
        self.distance_area = None
        self.calc_methods = [self.tr('Layer CRS'),
                             self.tr('Project CRS'),
                             self.tr('Ellipsoidal')]

    def initAlgorithm(self, config=None):
        self.addParameter(QgsProcessingParameterFeatureSource(self.INPUT,
                                                              self.tr('Input layer')))
        self.addParameter(QgsProcessingParameterEnum(self.METHOD,
                                                     self.tr('Calculate using'), options=self.calc_methods, defaultValue=0))
        self.addParameter(QgsProcessingParameterFeatureSink(self.OUTPUT, self.tr('Added geom info')))

    def name(self):
        return 'exportaddgeometrycolumns'

    def displayName(self):
        return self.tr('Export geometry columns')

    def processAlgorithm(self, parameters, context, feedback):
        source = self.parameterAsSource(parameters, self.INPUT, context)
        method = self.parameterAsEnum(parameters, self.METHOD, context)

        wkb_type = source.wkbType()
        fields = source.fields()

        new_fields = QgsFields()
        if QgsWkbTypes.geometryType(wkb_type) == QgsWkbTypes.PolygonGeometry:
            new_fields.append(QgsField('area', QVariant.Double))
            new_fields.append(QgsField('perimeter', QVariant.Double))
        elif QgsWkbTypes.geometryType(wkb_type) == QgsWkbTypes.LineGeometry:
            new_fields.append(QgsField('length', QVariant.Double))
        else:
            new_fields.append(QgsField('xcoord', QVariant.Double))
            new_fields.append(QgsField('ycoord', QVariant.Double))
            if QgsWkbTypes.hasZ(source.wkbType()):
                self.export_z = True
                new_fields.append(QgsField('zcoord', QVariant.Double))
            if QgsWkbTypes.hasM(source.wkbType()):
                self.export_m = True
                new_fields.append(QgsField('mvalue', QVariant.Double))

        fields = QgsProcessingUtils.combineFields(fields, new_fields)
        (sink, dest_id) = self.parameterAsSink(parameters, self.OUTPUT, context,
                                               fields, wkb_type, source.sourceCrs())

        coordTransform = None

        # Calculate with:
        # 0 - layer CRS
        # 1 - project CRS
        # 2 - ellipsoidal

        self.distance_area = QgsDistanceArea()
        if method == 2:
            self.distance_area.setSourceCrs(source.sourceCrs())
            self.distance_area.setEllipsoid(context.project().ellipsoid())
        elif method == 1:
            coordTransform = QgsCoordinateTransform(source.sourceCrs(), context.project().crs())

        features = source.getFeatures()
        total = 100.0 / source.featureCount() if source.featureCount() else 0
        for current, f in enumerate(features):
            if feedback.isCanceled():
                break

            outFeat = f
            attrs = f.attributes()
            inGeom = f.geometry()
            if inGeom:
                if coordTransform is not None:
                    inGeom.transform(coordTransform)

                if inGeom.type() == QgsWkbTypes.PointGeometry:
                    attrs.extend(self.point_attributes(inGeom))
                elif inGeom.type() == QgsWkbTypes.PolygonGeometry:
                    attrs.extend(self.polygon_attributes(inGeom))
                else:
                    attrs.extend(self.line_attributes(inGeom))

            outFeat.setAttributes(attrs)
            sink.addFeature(outFeat, QgsFeatureSink.FastInsert)

            feedback.setProgress(int(current * total))

        return {self.OUTPUT: dest_id}

    def point_attributes(self, geometry):
        pt = None
        if not geometry.isMultipart():
            pt = geometry.constGet()
        else:
            if geometry.numGeometries() > 0:
                pt = geometry.geometryN(0)
        attrs = []
        if pt:
            attrs.append(pt.x())
            attrs.append(pt.y())
            # add point z/m
            if self.export_z:
                attrs.append(pt.z())
            if self.export_m:
                attrs.append(pt.m())
        return attrs

    def line_attributes(self, geometry):
        return [self.distance_area.measureLength(geometry)]

    def polygon_attributes(self, geometry):
        area = self.distance_area.measureArea(geometry)
        perimeter = self.distance_area.measurePerimeter(geometry)
        return [area, perimeter]