1. import sys
2. from qgis.utils import iface
3. from qgis.core import *
4. from PyQt4 import QtGui
5. from PyQt4 import QtCore
6.  
7. FILES_FOLDER_PATH = "C:/Users/PawelW/Desktop/lab3/"
8.  
9. def main():
10.     exercise_1()
11.     exercise_2()
12.  
13. def exercise_1():
14.     clear()
15.  
16.     world_layer = load_layer('WORLD_RG/WORLD_RG_10M_2010.shp', "World")
17.     province_layer = load_layer('POL_adm/POL_adm1.shp', 'Province')
18.     country_layer = load_layer('POL_adm/POL_adm2.shp', 'Country')
19.  
20.     set_color(world_layer, 15, 163, 42)
21.     set_color(province_layer, 13, 76, 212)
22.     set_color(country_layer, 232, 5, 5)
23.  
24.     set_transparency(country_layer, 0.8)
25.  
26.     province_layer.selectAll()
27.     iface.mapCanvas().zoomToSelected(province_layer)
28.  
29. def exercise_2():
30.     clear()
31.     province_layer = load_layer('POL_adm/POL_adm1.shp', 'Province')
32.     fields(province_layer)
33.     provinces_list = get_provinces_list(province_layer)
34.     print(provinces_list)
35.     print(len(provinces_list))
36.     del_area(province_layer)
37.     areas_sizes_list = calculate_areas_size(province_layer)
38.     print(areas_sizes_list)
39.     print(len(areas_sizes_list))
40.     save_to_file(provinces_list, areas_sizes_list)
41.  
42. def error(info):
43.     print >> sys.stderr, "Error:", info
44.  
45. def load_layer(sub_path, name):
46.     layer = QgsVectorLayer(FILES_FOLDER_PATH + sub_path, name, "ogr")
47.     if not layer.isValid(): error("Layer :" + sub_path + " failed to load!")
48.     QgsMapLayerRegistry.instance().addMapLayer(layer)
49.     layer.setCacheImage(None)
50.     layer.triggerRepaint()
51.     return layer
52.  
53. def clear():
54.     for item in QgsMapLayerRegistry.instance().mapLayers().items():
55.         layer_id = item[1].id()
56.         QgsMapLayerRegistry.instance().removeMapLayer(layer_id)
57.        
58. def set_color(layer, r=0, g=0, b=0):
59.     if r<0.0: r=0
60.     if r>255.0: r=255
61.     if g<0.0: g=0
62.     if g>255.0: g=255
63.     if b<0.0: b=0
64.     if b>255.0: b=255
65.     myRenderer = layer.rendererV2()
66.     mySymbol = myRenderer.symbol()
67.     mySymbol.setColor(QtGui.QColor(r,g,b))
68.     layer.setCacheImage(None)
69.     layer.triggerRepaint()
70.     iface.mapCanvas().refresh()
71.  
72. def set_transparency(layer, tval=0.5):
73.     if tval<0.0: tval=0
74.     if tval>1.0: tval=1
75.     tval = 1.0 - tval
76.     myRenderer = layer.rendererV2()
77.     mySymbol = myRenderer.symbol()
78.     mySymbol.setAlpha(tval)
79.     layer.setCacheImage(None)
80.     layer.triggerRepaint()
81.     iface.mapCanvas().refresh()
82.  
83. def fields(layer):
84.     provider = layer.dataProvider()
85.     table = provider.fields()
86.     print("Field names:")
87.     for field in table:
88.         print(field.name())
89.  
90. def get_provinces_list(layer):
91.     provinces_list = []
92.     provider = layer.dataProvider()
93.     feature_list = provider.getFeatures()
94.     feat = QgsFeature()
95.     while feature_list.nextFeature(feat):
96.         attrs = feat.attributes()
97.         provinces_list.append(attrs[6].encode('utf-8'))
98.     return provinces_list
99.  
100. def del_area(layer, nr=9):
101.     if not layer.isEditable():
102.         layer.startEditing()
103.     res = layer.deleteAttribute( nr )
104.     layer.commitChanges()
105.  
106. def calculate_areas_size(layer):
107.     areas_list = []
108.     if not layer.isEditable():
109.         layer.startEditing()
110.     lProvider = layer.dataProvider()
111.     lProvider.addAttributes([QgsField('area', QtCore.QVariant.Double)])
112.     for feature in layer.getFeatures():
113.         calculator = QgsDistanceArea()
114.         calculator.computeAreaInit()
115.         geometry = feature.geometry()
116.         sum_area = 0
117.         if not geometry.isMultipart():
118.             polygon = geometry.asPolygon()
119.             if len(polygon) > 0:
120.                 degrees = calculator.measurePolygon(polygon[0])
121.                 area = calculator.convertMeasurement(degrees, QGis.Degrees, QGis.Meters, True)
122.                 sum_area += area[0]
123.             print("if", sum_area)
124.         else:
125.             multi_polygon = geometry.asMultiPolygon()
126.             for sub_polygon in multi_polygon:
127.                 degrees = calculator.measurePolygon(sub_polygon[0])
128.                 area = calculator.convertMeasurement(degrees, QGis.Degrees, QGis.Meters, True)
129.                 sum_area += area[0]
130.             print("else", sum_area)
131.         areas_list.append(sum_area)
132.         layer.changeAttributeValue(0, 9, sum_area)
133.         layer.commitChanges()
134.     return areas_list
135.  
136. def save_to_file(names, areas):
137.     result = open(FILES_FOLDER_PATH + 'result.txt', "w+")
138.     result.write("Numer            Nazwa         Powierzchnia  \n")
139.  
140.     for i in range(len(names)):
141.         result.write(str(i+1) + ".  " + names[i] + "   " + str(areas[i]/1000000) + " km kwadratowych\n")
142.     result.close()
143.  
144. if __name__ == '__main__':
145.     main()
146.  
147.