QGIS/python/plugins/processing/algs/qgis/PointsAlongGeometry.py
2017-08-22 23:36:42 +10:00

133 lines
5.3 KiB
Python

# -*- coding: utf-8 -*-
"""
***************************************************************************
PointsAlongGeometry.py
---------------------
Date : August 2016
Copyright : (C) 2016 by Nyall Dawson
Email : nyall dot dawson 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__ = 'Nyall Dawson'
__date__ = 'August 2016'
__copyright__ = '(C) 2016, Nyall Dawson'
# This will get replaced with a git SHA1 when you do a git archive
__revision__ = '$Format:%H$'
import os
import math
from qgis.PyQt.QtCore import QVariant
from qgis.PyQt.QtGui import QIcon
from qgis.core import (QgsFeature,
QgsFeatureSink,
QgsWkbTypes,
QgsField,
QgsProcessing,
QgsProcessingUtils,
QgsProcessingParameterNumber,
QgsProcessingParameterFeatureSource,
QgsProcessingParameterFeatureSink)
from processing.algs.qgis.QgisAlgorithm import QgisAlgorithm
pluginPath = os.path.split(os.path.split(os.path.dirname(__file__))[0])[0]
class PointsAlongGeometry(QgisAlgorithm):
INPUT = 'INPUT'
OUTPUT = 'OUTPUT'
DISTANCE = 'DISTANCE'
START_OFFSET = 'START_OFFSET'
END_OFFSET = 'END_OFFSET'
def icon(self):
return QIcon(os.path.join(pluginPath, 'images', 'ftools', 'extract_nodes.png'))
def tags(self):
return self.tr('create,interpolate,points,lines').split(',')
def group(self):
return self.tr('Vector geometry')
def __init__(self):
super().__init__()
def initAlgorithm(self, config=None):
self.addParameter(QgsProcessingParameterFeatureSource(self.INPUT,
self.tr('Input layer'), [QgsProcessing.TypeVectorPolygon, QgsProcessing.TypeVectorLine]))
self.addParameter(QgsProcessingParameterNumber(self.DISTANCE,
self.tr('Distance'), minValue=0.0, defaultValue=1.0))
self.addParameter(QgsProcessingParameterNumber(self.START_OFFSET,
self.tr('Start offset'), minValue=0.0, defaultValue=0.0))
self.addParameter(QgsProcessingParameterNumber(self.END_OFFSET,
self.tr('End offset'), minValue=0.0, defaultValue=0.0))
self.addParameter(QgsProcessingParameterFeatureSink(self.OUTPUT, self.tr('Points'), QgsProcessing.TypeVectorPoint))
def name(self):
return 'pointsalonglines'
def displayName(self):
return self.tr('Points along lines')
def processAlgorithm(self, parameters, context, feedback):
source = self.parameterAsSource(parameters, self.INPUT, context)
distance = self.parameterAsDouble(parameters, self.DISTANCE, context)
start_offset = self.parameterAsDouble(parameters, self.START_OFFSET, context)
end_offset = self.parameterAsDouble(parameters, self.END_OFFSET, context)
fields = source.fields()
fields.append(QgsField('distance', QVariant.Double))
fields.append(QgsField('angle', QVariant.Double))
(sink, dest_id) = self.parameterAsSink(parameters, self.OUTPUT, context,
fields, QgsWkbTypes.Point, source.sourceCrs())
features = source.getFeatures()
total = 100.0 / source.featureCount() if source.featureCount() else 0
for current, input_feature in enumerate(features):
if feedback.isCanceled():
break
input_geometry = input_feature.geometry()
if not input_geometry:
sink.addFeature(input_feature, QgsFeatureSink.FastInsert)
else:
if input_geometry.type == QgsWkbTypes.PolygonGeometry:
length = input_geometry.geometry().perimeter()
else:
length = input_geometry.length() - end_offset
current_distance = start_offset
while current_distance <= length:
point = input_geometry.interpolate(current_distance)
angle = math.degrees(input_geometry.interpolateAngle(current_distance))
output_feature = QgsFeature()
output_feature.setGeometry(point)
attrs = input_feature.attributes()
attrs.append(current_distance)
attrs.append(angle)
output_feature.setAttributes(attrs)
sink.addFeature(output_feature, QgsFeatureSink.FastInsert)
current_distance += distance
feedback.setProgress(int(current * total))
return {self.OUTPUT: dest_id}