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[processing] add Regular points algorithm (addresses #5953)

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alexbruy committed Sep 15, 2014
1 parent b862420 commit ae4a1441e94f5628142ca5bad0ea7ce04de72d7a
@@ -31,6 +31,7 @@
from PyQt4.QtGui import *

from processing.core.AlgorithmProvider import AlgorithmProvider
from ftools.RegularPoints import RegularPoints

from RandomExtract import RandomExtract
from RandomExtractWithinSubsets import RandomExtractWithinSubsets
@@ -145,7 +146,8 @@ def __init__(self):
RandomSelection(), RandomSelectionWithinSubsets(),
SelectByLocation(), RandomExtract(),
RandomExtractWithinSubsets(), ExtractByLocation(),
SpatialJoin(), DeleteColumn(),
SpatialJoin(), RegularPoints(),
DeleteColumn(),
DeleteDuplicateGeometries(), TextToFloat(),
ExtractByAttribute(), SelectByAttribute(), Grid(),
Gridify(), HubDistance(), HubLines(), Merge(),
@@ -0,0 +1,118 @@
# -*- coding: utf-8 -*-

"""
***************************************************************************
RegularPoints.py
---------------------
Date : September 2014
Copyright : (C) 2014 by Alexander Bruy
Email : alexander dot bruy 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__ = 'Alexander Bruy'
__date__ = 'September 2014'
__copyright__ = '(C) 2014, Alexander Bruy'

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

__revision__ = '$Format:%H$'

from random import *

from PyQt4.QtCore import *
from qgis.core import *
from qgis.utils import iface

from processing.core.GeoAlgorithm import GeoAlgorithm
from processing.core.parameters import ParameterExtent
from processing.core.parameters import ParameterNumber
from processing.core.parameters import ParameterBoolean
from processing.core.outputs import OutputVector
from processing.tools import vector


class RegularPoints(GeoAlgorithm):

EXTENT = 'EXTENT'
SPACING = 'SPACING'
INSET = 'INSET'
RANDOMIZE = 'RANDOMIZE'
IS_SPACING = 'IS_SPACING'
OUTPUT = 'OUTPUT'

def defineCharacteristics(self):
self.name = 'Regular points'
self.group = 'Vector creation tools'

self.addParameter(ParameterExtent(self.EXTENT, 'Input extent'))
self.addParameter(ParameterNumber(self.SPACING,
'Point spacing/count', 0.0001, 999999999.999999999, 0.0001))
self.addParameter(ParameterNumber(self.INSET,
'Initial inset from corner (LH side)', 0.0, 9999.9999, 0.0))
self.addParameter(ParameterBoolean(self.RANDOMIZE,
'Apply random offset to point spacing', False))
self.addParameter(ParameterBoolean(self.IS_SPACING,
'Use point spacing', True))
self.addOutput(OutputVector(self.OUTPUT, 'Regular points'))

def processAlgorithm(self, progress):
extent = str(self.getParameterValue(self.EXTENT)).split(',')

spacing = float(self.getParameterValue(self.SPACING))
inset = float(self.getParameterValue(self.INSET))
randomize = self.getParameterValue(self.RANDOMIZE)
isSpacing = self.getParameterValue(self.IS_SPACING)

extent = QgsRectangle(float(extent[0]), float(extent[2]),
float(extent[1]), float(extent[3]))

fields = QgsFields()
fields.append(QgsField('id', QVariant.Int, '', 10, 0))
mapCRS = iface.mapCanvas().mapSettings().destinationCrs()

writer = self.getOutputFromName(self.OUTPUT).getVectorWriter(
fields, QGis.WKBPoint, mapCRS)

if randomize:
seed()

area = extent.width() * extent.height()
if isSpacing:
pSpacing = spacing
else:
pSpacing = sqrt(area / value)

f = QgsFeature()
f.initAttributes(1)
f.setFields(fields)

count = 0
total = 100.00 / (area / pSpacing)
y = extent.yMaximum() - inset
while y >= extent.yMinimum():
x = extent.xMinimum() + inset
while x <= extent.xMaximum():
if randomize:
geom = QgsGeometry().fromPoint(QgsPoint(
uniform(x - (pSpacing / 2.0), x + (pSpacing / 2.0)),
uniform(y - (pSpacing / 2.0), y + (pSpacing / 2.0))))
else:
geom = QgsGeometry().fromPoint(QgsPoint(x, y))

if geom.intersects(extent):
f.setAttribute('id', count)
f.setGeometry(geom)
writer.addFeature(f)
x += pSpacing
count += 1
progress.setPercentage(int(count* total))
y = y - pSpacing
del writer

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