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refactor Hub distance alg

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alexbruy committed Oct 3, 2014
1 parent d4dbb92 commit f6144355b36aa5c5844bd5169770badab2db7540
@@ -80,6 +80,7 @@
from mmqgisx.SelectByAttribute import SelectByAttribute
from mmqgisx.Grid import Grid
from mmqgisx.Gridify import Gridify
from mmqgisx.HubDistance import HubDistance

from ConcaveHull import ConcaveHull
from Polygonize import Polygonize
@@ -146,7 +147,7 @@ def __init__(self):
# ------ mmqgisx ------
DeleteColumn(), DeleteDuplicateGeometries(),
TextToFloat(), ExtractByAttribute(),
SelectByAttribute(), Grid(), Gridify(),
SelectByAttribute(), Grid(), Gridify(), HubDistance(),
#mmqgisx_delete_duplicate_geometries_algorithm(),
#mmqgisx_geometry_convert_algorithm(),
#mmqgisx_grid_algorithm(),
@@ -0,0 +1,160 @@
# -*- coding: utf-8 -*-

"""
***************************************************************************
Gridify.py
---------------------
Date : May 2010
Copyright : (C) 2010 by Michael Minn
Email : pyqgis at michaelminn 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__ = 'Michael Minn'
__date__ = 'May 2010'
__copyright__ = '(C) 2010, Michael Minn'

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

__revision__ = '$Format:%H$'

from PyQt4.QtCore import *
from qgis.core import *
from processing.core.GeoAlgorithm import GeoAlgorithm
from processing.core.GeoAlgorithmExecutionException import \
GeoAlgorithmExecutionException
from processing.core.parameters import ParameterVector
from processing.core.parameters import ParameterTableField
from processing.core.parameters import ParameterSelection
from processing.core.outputs import OutputVector

from processing.tools import dataobjects, vector

class HubDistance(GeoAlgorithm):
POINTS = 'POINTS'
HUBS = 'HUBS'
FIELD = 'FIELD'
GEOMETRY = 'GEOMETRY'
UNIT = 'UNIT'
OUTPUT = 'OUTPUT'

GEOMETRIES = ['Point',
'Line to hub'
]

UNITS = ['Meters',
'Feet',
'Miles',
'Kilometers',
'Layer units'
]

def defineCharacteristics(self):
self.name = 'Distance to nearest hub'
self.group = 'Vector analysis tools'

self.addParameter(ParameterVector(self.POINTS,
'Source points layer', [ParameterVector.VECTOR_TYPE_ANY]))
self.addParameter(ParameterVector(self.HUBS,
'Destination hubs layer', [ParameterVector.VECTOR_TYPE_ANY]))
self.addParameter(ParameterTableField(
self.FIELD, 'Hub layer name attribute', self.HUBS))
self.addParameter(ParameterSelection(
self.GEOMETRY, 'Output shape type', self.GEOMETRIES))
self.addParameter(ParameterSelection(
self.UNIT, 'Measurement unit', self.UNITS))

self.addOutput(OutputVector(self.OUTPUT, 'Output'))

def processAlgorithm(self, progress):
layerPoints = dataobjects.getObjectFromUri(
self.getParameterValue(self.POINTS))
layerHubs = dataobjects.getObjectFromUri(
self.getParameterValue(self.HUBS))
fieldName = self.getParameterValue(self.FIELD)

addLines = self.getParameterValue(self.GEOMETRY)
units = self.UNITS[self.getParameterValue(self.UNIT)]

if layerPoints.source() == layerHubs.source():
raise GeoAlgorithmExecutionException(
'Same layer given for both hubs and spokes')

geomType = QGis.WKBPoint
if addLines:
geomType = QGis.WKBLineString

fields = layerPoints.pendingFields()
fields.append(QgsField('HubName', QVariant.String))
fields.append(QgsField('HubDist', QVariant.Double))

writer = self.getOutputFromName(self.OUTPUT).getVectorWriter(
fields, geomType, layerPoints.crs())

# Create array of hubs in memory
hubs = []
features = vector.features(layerHubs)
for f in features:
hubs.append(Hub(f.geometry().boundingBox().center(),
unicode(f[fieldName])))

distance = QgsDistanceArea()
distance.setSourceCrs(layerPoints.crs().srsid())
distance.setEllipsoidalMode(True)

# Scan source points, find nearest hub, and write to output file
features = vector.features(layerPoints)
count = len(features)
total = 100.0 / float(count)
for count, f in enumerate(features):
src = f.geometry().boundingBox().center()

closest = hubs[0]
hubDist = distance.measureLine(src, closest.point)

for hub in hubs:
dist = distance.measureLine(src, hub.point)
if dist < hubDist:
closest = hub
hubDist = dist

attributes = f.attributes()
attributes.append(closest.name)
if units == 'Feet':
attributes.append(hubDist * 3.2808399)
elif units == 'Miles':
attributes.append(hubDist * 0.000621371192)
elif units == 'Kilometers':
attributes.append(hubDist / 1000.0)
elif units != 'Meters':
attributes.append(sqrt(
pow(source.x() - closest.point.x(), 2.0) +
pow(source.y() - closest.point.y(), 2.0)))
else:
attributes.append(hubDist)

feat = QgsFeature()
feat.setAttributes(attributes)

if geomType == QGis.WKBPoint:
feat.setGeometry(QgsGeometry.fromPoint(src))
else:
feat.setGeometry(QgsGeometry.fromPolyline([src, closest.point]))

writer.addFeature(feat)
progress.setPercentage(int(count * total))

del writer


class Hub:
def __init__(self, point, name):
self.point = point
self.name = name

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