QGIS/python/plugins/processing/algs/qgis/PointsAlongGeometry.py
2017-06-06 13:41:42 +10:00

122 lines
4.8 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, QgsWkbTypes, QgsField, QgsProcessingUtils
from processing.algs.qgis.QgisAlgorithm import QgisAlgorithm
from processing.core.parameters import ParameterVector, ParameterNumber
from processing.core.outputs import OutputVector
from processing.tools import dataobjects
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 tools')
def __init__(self):
super().__init__()
self.addParameter(ParameterVector(self.INPUT,
self.tr('Input layer'),
[dataobjects.TYPE_VECTOR_POLYGON, dataobjects.TYPE_VECTOR_LINE]))
self.addParameter(ParameterNumber(self.DISTANCE,
self.tr('Distance'), default=1.0))
self.addParameter(ParameterNumber(self.START_OFFSET,
self.tr('Start offset'), default=0.0))
self.addParameter(ParameterNumber(self.END_OFFSET,
self.tr('End offset'), default=0.0))
self.addOutput(OutputVector(self.OUTPUT, self.tr('Points'), datatype=[dataobjects.TYPE_VECTOR_POINT]))
def name(self):
return 'pointsalonglines'
def displayName(self):
return self.tr('Points along lines')
def processAlgorithm(self, parameters, context, feedback):
layer = QgsProcessingUtils.mapLayerFromString(self.getParameterValue(self.INPUT), context)
distance = self.getParameterValue(self.DISTANCE)
start_offset = self.getParameterValue(self.START_OFFSET)
end_offset = self.getParameterValue(self.END_OFFSET)
fields = layer.fields()
fields.append(QgsField('distance', QVariant.Double))
fields.append(QgsField('angle', QVariant.Double))
writer = self.getOutputFromName(self.OUTPUT).getVectorWriter(fields, QgsWkbTypes.Point, layer.crs(), context)
features = QgsProcessingUtils.getFeatures(layer, context)
total = 100.0 / QgsProcessingUtils.featureCount(layer, context)
for current, input_feature in enumerate(features):
input_geometry = input_feature.geometry()
if not input_geometry:
writer.addFeature(input_feature)
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)
writer.addFeature(output_feature)
current_distance += distance
feedback.setProgress(int(current * total))
del writer