Changed the Shapely polygon creation from WKT to WKB to speed up the processing

exposurejapan/database.py

@@ -22,6 +22,7 @@ import pandas
 import numpy
 import constants
 import shapely.wkt
+import shapely.wkb
 import pyproj
 from shapely.ops import transform
 import csv
@@ -634,11 +635,11 @@ class JapanDatabase(SpatialiteDatabase):
 
         # Calculate the area for each district using Albers equal area transformation
         # and update the Districts table
-        sql_statement = "SELECT id, ST_AsText(geom) FROM District"
+        sql_statement = "SELECT id, AsBinary(geom) FROM District"
         self.cursor.execute(sql_statement)
         districts = self.cursor.fetchall()
         for district in districts:
-            district_geom = shapely.wkt.loads(district[1])
+            district_geom = shapely.wkb.loads(district[1])
             district_size = (
                 self.albers_area_calculation(district_geom, "epsg:%d" % constants.WGS84)
                 * 0.000001  # Convert from square meters to square kilometers