Votre question m'a rendu curieux.
Cette solution fonctionne uniquement pour QGIS 2.x dans la console Python
Comme mentionné dans mon commentaire, voici mon idée de créer l'arc de lignes avec Python.
J'ai une couche à deux points:
je. Un tenant le capital (id, capital)
ii. Un tenant les villes (id, ville, navetteurs)
Le nombre de navetteurs est "séparé en billets de banque" et ce seront les lignes qui construiront l'arc. Ainsi, 371 navetteurs sont une combinaison de 3x100, 1x50, 2x10 et 1x1 et au total 7 billets. Ensuite, les lignes sont stylisées par un style basé sur des règles.
Voici le code:
from qgis.gui import *
from qgis.utils import *
from qgis.core import *
from PyQt4 import QtGui, uic
from PyQt4.QtGui import *
from PyQt4.QtCore import *
for lyr in QgsMapLayerRegistry.instance().mapLayers().values():
if lyr.name() == "capital":
capital_layer = lyr
for lyr in QgsMapLayerRegistry.instance().mapLayers().values():
if lyr.name() == "town":
town_layer = lyr
# creating the memory layer
d_lyr = QgsVectorLayer('LineString', 'distance', 'memory')
QgsMapLayerRegistry.instance().addMapLayer(d_lyr)
prov = d_lyr.dataProvider()
prov.addAttributes( [ QgsField("id", QVariant.Int), QgsField("banknote",QVariant.Int)])
# function to create the banknotes
def banknoteOutput(number):
number_list = []
number_list.append(number)
banknote_count = []
temp_list = []
banknote_list = []
for n in number_list:
total_sum = 0
total = int(n/100)
total_sum = total_sum + total
if total > 0:
banknote_count.append([total, 100])
n = n-(total*100)
total = int(n/50)
total_sum = total_sum + total
if total > 0:
banknote_count.append([total, 50])
n = n-(total*50)
total = int(n/10)
total_sum = total_sum + total
if total > 0:
banknote_count.append([total, 10])
n = n-(total*10)
total = int(n/5)
total_sum = total_sum + total
if total > 0:
banknote_count.append([total, 5])
n = n-(total*5)
total = int(n/1)
total_sum = total_sum + total
if total > 0:
banknote_count.append([total, 1])
for i in banknote_count:
temp_list.append(i*i[0])
banknote_list = [item for sublist in temp_list for item in sublist][1::2]
return banknote_list
# creating lines with the amount of banknotes
for capital in capital_layer.getFeatures():
for town in town_layer.getFeatures():
commuter_splitting = banknoteOutput(town['commuters'])
for i,banknote in enumerate(commuter_splitting):
angle = 2
distance = QgsDistanceArea()
distance.measureLine(capital.geometry().asPoint(), town.geometry().asPoint())
vect = QgsFeature()
vect.setGeometry(QgsGeometry.fromPolyline([capital.geometry().asPoint(), town.geometry().asPoint()]))
vect.geometry().rotate(0+(i*angle), capital.geometry().asPoint())
vect.setAttributes([int(town["id"]), int(banknote)])
prov.addFeatures([vect])
d_lyr.updateExtents()
d_lyr.triggerRepaint()
d_lyr.updateFields()
Le résultat pourrait ressembler à ceci:
MISE À JOUR: distinction homme / femme
Résultats en 4 couches mémoire.
from qgis.gui import *
from qgis.utils import *
from qgis.core import *
from PyQt4 import QtGui, uic
from PyQt4.QtGui import *
from PyQt4.QtCore import *
for lyr in QgsMapLayerRegistry.instance().mapLayers().values():
if lyr.name() == "capital":
capital_layer = lyr
for lyr in QgsMapLayerRegistry.instance().mapLayers().values():
if lyr.name() == "town":
town_layer = lyr
# function to create the banknotes
def banknoteOutput(number):
number_list = []
number_list.append(number)
banknote_count = []
temp_list = []
banknote_list = []
for n in number_list:
total_sum = 0
total = int(n/100)
total_sum = total_sum + total
if total > 0:
banknote_count.append([total, 100])
n = n-(total*100)
total = int(n/50)
total_sum = total_sum + total
if total > 0:
banknote_count.append([total, 50])
n = n-(total*50)
total = int(n/10)
total_sum = total_sum + total
if total > 0:
banknote_count.append([total, 10])
n = n-(total*10)
total = int(n/5)
total_sum = total_sum + total
if total > 0:
banknote_count.append([total, 5])
n = n-(total*5)
total = int(n/1)
total_sum = total_sum + total
if total > 0:
banknote_count.append([total, 1])
for i in banknote_count:
temp_list.append(i*i[0])
banknote_list = [item for sublist in temp_list for item in sublist][1::2]
return banknote_list
# creating the male memory layer
cmt_male = QgsVectorLayer('LineString', 'Commuters_Male', 'memory')
QgsMapLayerRegistry.instance().addMapLayer(cmt_male)
prov_male = cmt_male.dataProvider()
prov_male.addAttributes( [ QgsField("id", QVariant.Int), QgsField("banknote",QVariant.Int)])
# creating the male polygon memory layer
cmt_male_polygon = QgsVectorLayer('Polygon', 'Commuters_Male_Poly', 'memory')
QgsMapLayerRegistry.instance().addMapLayer(cmt_male_polygon)
prov_cmt_male_polygon = cmt_male_polygon.dataProvider()
prov_cmt_male_polygon.addAttributes( [ QgsField("id", QVariant.Int), QgsField("banknote",QVariant.Int)])
# creating lines with the amount of banknotes
for capital in capital_layer.getFeatures():
for town in town_layer.getFeatures():
commuter_splitting = banknoteOutput(town['cmt_male'])
points = []
for i,banknote in enumerate(reversed(commuter_splitting)):
angle = 2
distance = QgsDistanceArea()
distance.measureLine(capital.geometry().asPoint(), town.geometry().asPoint())
vect = QgsFeature()
vect.setGeometry(QgsGeometry.fromPolyline([capital.geometry().asPoint(), town.geometry().asPoint()]))
vect.geometry().rotate(0+(i*angle), capital.geometry().asPoint())
vect.setAttributes([int(town["id"]), int(banknote)])
points.append(vect.geometry().asPolyline()[1])
prov_male.addFeatures([vect])
polygon = QgsFeature()
points.insert(0,capital.geometry().asPoint())
points.insert(len(points),capital.geometry().asPoint())
polygon.setGeometry(QgsGeometry.fromPolygon([points]))
polygon.setAttributes([1, 2])
prov_cmt_male_polygon.addFeatures([polygon])
cmt_male.updateExtents()
cmt_male.triggerRepaint()
cmt_male.updateFields()
cmt_male_polygon.updateExtents()
cmt_male_polygon.triggerRepaint()
cmt_male_polygon.updateFields()
# creating the female memory layer
cmt_female = QgsVectorLayer('LineString', 'Commuters_Female', 'memory')
QgsMapLayerRegistry.instance().addMapLayer(cmt_female)
prov_female = cmt_female.dataProvider()
prov_female.addAttributes( [ QgsField("id", QVariant.Int), QgsField("banknote",QVariant.Int)])
# creating the female polygon memory layer
cmt_female_polygon = QgsVectorLayer('Polygon', 'Commuters_Female_Poly', 'memory')
QgsMapLayerRegistry.instance().addMapLayer(cmt_female_polygon)
prov_cmt_female_polygon = cmt_female_polygon.dataProvider()
prov_cmt_female_polygon.addAttributes( [ QgsField("id", QVariant.Int), QgsField("banknote",QVariant.Int)])
# creating lines with the amount of banknotes
for capital in capital_layer.getFeatures():
for town in town_layer.getFeatures():
commuter_splitting = banknoteOutput(town['cmt_female'])
points = []
for i,banknote in enumerate(commuter_splitting):
angle = 2
distance = QgsDistanceArea()
distance.measureLine(capital.geometry().asPoint(), town.geometry().asPoint())
vect = QgsFeature()
vect.setGeometry(QgsGeometry.fromPolyline([capital.geometry().asPoint(), town.geometry().asPoint()]))
vect.geometry().rotate(-angle-(i*angle), capital.geometry().asPoint())
vect.setAttributes([int(town["id"]), int(banknote)])
points.append(vect.geometry().asPolyline()[1])
prov_female.addFeatures([vect])
polygon = QgsFeature()
points.insert(0,capital.geometry().asPoint())
points.insert(len(points),capital.geometry().asPoint())
polygon.setGeometry(QgsGeometry.fromPolygon([points]))
polygon.setAttributes([1, 2])
prov_cmt_female_polygon.addFeatures([polygon])
cmt_female.updateExtents()
cmt_female.triggerRepaint()
cmt_female.updateFields()
cmt_female_polygon.updateExtents()
cmt_female_polygon.triggerRepaint()
cmt_female_polygon.updateFields()
Le résultat pourrait ressembler à ceci:
Une chose qui n'est pas idéale d'un point de vue cartographique:
La taille d'un arc de ligne peut être irritante à première vue, dans la mesure où un arc plus grand pourrait représenter plus de navetteurs. Un arc peut être plus grand avec moins de navetteurs (289 navetteurs / 11 billets) qu'un autre avec plus de navetteurs (311 navetteurs / 5 billets).
