Making silly maps for fun and profit

every_election/apps/organisations/management/commands/create_svg_thumbs.py

@@ -0,0 +1,205 @@
+import re
+
+from django.core.management import BaseCommand
+from django.db import connection
+
+
+class SVGGenerator:
+    def __init__(self, object_id, object_type="divisiongeography"):
+        self.object_type = object_type
+        self.object_id = object_id
+        self.cursor = connection.cursor()
+
+        self.svg_layers = []
+
+        self.object_svg = self.get_object_svg()
+        self.touching_svg = self.get_touching_svg()
+
+        self.svg_layers.append(self.style_touching(self.touching_svg))
+        self.svg_layers.append(self.style_division(self.object_svg))
+        self.svg_layers += self.get_buildings()
+        self.svg_layers += self.get_roads()
+
+
+    def style_touching(self, touching):
+        return "\n".join(
+            [
+                f"""<path d="{path}" fill="#EEE" style="stroke-width:{{width}};stroke:#CCC;stroke-opacity:1" />"""
+                for path in touching
+            ]
+        )
+
+    def style_division(self, division):
+        return "\n".join(
+            [
+                f"""<path d="{path}" fill="#E6007C" style="stroke-width:{{width}};stroke:#000;stroke-opacity:0.2" />"""
+                for path in division
+            ]
+        )
+
+    def get_viewbox(self):
+        def _float_if_float(input):
+            try:
+                return float(input)
+            except ValueError:
+                return None
+
+        x_max = -1000
+        x_min = 1000
+        y_max = -1000
+        y_min = 1000
+        for svg in self.svg_layers:
+            cleaned = re.sub("[A-Za-z]", "", svg)
+            cleaned = re.sub("[\s]+", " ", cleaned).strip()
+            x_list = []
+            y_list = []
+            for i, part in enumerate(cleaned.split(" ")):
+                floated = _float_if_float(part)
+                if not floated:
+                    continue
+                if i % 2:
+                    add_to = y_list
+                else:
+                    add_to = x_list
+                add_to.append(floated)
+
+            x_max = max(
+                x_max, max([_float_if_float(x) for x in x_list if
+                            _float_if_float(x)])
+            )
+            x_min = min(
+                x_min, min([_float_if_float(x) for x in x_list if
+                            _float_if_float(x)])
+            )
+            y_max = max(
+                y_max, max([_float_if_float(x) for x in y_list if
+                            _float_if_float(x)])
+            )
+            y_min = min(
+                y_min, min([_float_if_float(x) for x in y_list if
+                            _float_if_float(x)])
+            )
+
+        # print("-0.38996970653533936 -53.20250701904297 0.2129676789045334 0.2129669189453125")
+        self.width = x_max - x_min
+        self.height = y_max - y_min
+        self.viewport = f"{x_min} {y_min} {self.width} {self.height}"
+        # print(viewport)
+        return self.viewport
+        # import sys
+        # sys.exit()
+        # return
+
+    def write_svg(self):
+        viewbox = self.get_viewbox()
+        paths = "\n".join(path.format(width=self.width * 0.004) for path in
+                          self.svg_layers)
+        print(
+            f"""
+        <svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" style="background-color:#99ccff" height="800" width="800" viewBox="{viewbox}">
+        {paths}
+        </svg>
+        """
+        )
+
+    def get_buildings(self):
+        sql = """ 
+        SELECT st_assvg(geom) 
+        FROM buildings   
+        WHERE st_coveredby(
+            geom, 
+            (SELECT dg.geography
+                FROM organisations_divisiongeography dg 
+                WHERE division_id = %s)
+            ) 
+        """ % (self.object_id, )
+        self.cursor.execute(sql)
+        svg_list = [
+            f"""<path d="{row[0]}" fill="black" style="stroke-width:0.00002;stroke:#000;stroke-opacity:1" />"""
+            for row in self.cursor.fetchall()]
+
+        return svg_list
+
+    def get_roads(self):
+        sql = """ 
+        SELECT st_assvg(geom) 
+        FROM roads   
+        WHERE st_coveredby(
+            geom, 
+            (SELECT st_envelope(
+                        ST_MinimumBoundingCircle(
+                            st_envelope(
+                                dg.geography
+                            )
+                        )
+                    ) 
+                FROM organisations_divisiongeography dg 
+                WHERE division_id = %s)
+            ) 
+        """ % (self.object_id, )
+        self.cursor.execute(sql)
+        svg_list = [
+            f"""<path d="{row[0]}" fill="none" style="stroke-width:0.00001;stroke:#000;stroke-opacity:1" />"""
+            for row in self.cursor.fetchall()]
+
+        return svg_list
+
+    def get_touching_svg(self):
+        sql = """
+        SELECT 
+            st_assvg(st_intersection(
+                (
+                    SELECT 
+                    st_envelope(
+                        ST_MinimumBoundingCircle(
+                            st_envelope(
+                                dg.geography
+                            )
+                        )
+                    ) as gg 
+                    FROM organisations_divisiongeography dg 
+                    WHERE division_id = %s
+                ),
+                dg.geography
+            )) as gg
+        FROM organisations_divisiongeography dg
+        WHERE ST_Overlaps(
+                (
+                    SELECT 
+                    st_envelope(
+                        ST_MinimumBoundingCircle(
+                            st_envelope(
+                                dg.geography
+                            )
+                        )
+                    ) as gg 
+                    FROM organisations_divisiongeography dg 
+                    WHERE division_id = %s
+                )
+                , 
+                dg.geography
+                
+        )
+        """ % (self.object_id, self.object_id)
+
+        self.cursor.execute(sql)
+        svg_list = [row[0] for row in self.cursor.fetchall()]
+        return svg_list
+
+    def get_object_svg(self):
+        sql = """
+                SELECT 
+                    st_assvg(dg.geography)
+                FROM organisations_divisiongeography dg 
+                WHERE division_id = %s
+                """ % self.object_id
+
+        self.cursor.execute(sql)
+        svg_list = [row[0] for row in self.cursor.fetchall()]
+        return svg_list
+
+
+class Command(BaseCommand):
+    def handle(self, *args, **options):
+        svg = SVGGenerator(21888)
+        svg.write_svg()