Add GPX generation

to_gpx.py

@@ -0,0 +1,30 @@
+import json
+from html import escape
+
+with open('data.json') as data_file:
+    data = json.load(data_file)
+
+with open('Megaliths.gpx', 'w') as gpx_file:
+    gpx_file.write('''<?xml version="1.0" encoding="UTF-8"?>
+<gpx xmlns="http://www.topografix.com/GPX/1/1" 
+     version="1.1" 
+     creator="megalithosm" 
+     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
+     xsi:schemaLocation="http://www.topografix.com/GPX/1/1 http://www.topografix.com/GPX/1/1/gpx.xsd">
+    <metadata>
+        <name>Megalith sites</name>
+        <author>
+           <name>Jude Southworth</name>
+        </author>
+    </metadata>''')
+
+    for poi in data:
+        gpx_file.write(
+            '''
+    <wpt lat="{}" lon="{}">
+        <name>{}</name>
+        <type>{}</type>
+        <url>{}</url>
+    </wpt>'''.format(poi['lat'], poi['lng'], escape(poi['name']), poi['type'], poi['url'])
+        )
+    gpx_file.write('</gpx>')