Add build_city.sh script

.gitignore

@@ -8,3 +8,4 @@ html/
 *.swp
 *.yaml
 *.pyc
+*.txt

README.md

@@ -32,6 +32,11 @@ scripts/process_subways.sh
 
 The bounding box can be found in the
 [Google Spreadsheet](https://docs.google.com/spreadsheets/d/1-UHDzfBwHdeyFxgC5cE_MaNQotF3-Y0r1nW9IwpIEj8/edit?usp=sharing).
+
+This can be simplified by using the `build_city.sh` script, which fetches the bbox from the web:
+
+    scripts/build_city.sh london.o5m London
+
 If you are okay with rare updates, use [this website](http://osmz.ru/subways/).
 
 ## Adding Stop Areas To OSM

scripts/build_city.sh

@@ -0,0 +1,16 @@
+#!/bin/bash
+set -e -u
+[ $# -lt 1 ] && echo "Usage: $0 <path_to_o5m> [<city_name> [<bbox>]]" && exit 1
+
+export OSMCTOOLS="${OSMCTOOLS:-$HOME/osm/planet}"
+export DUMP=html
+export JSON=html
+if [ -n "${2-}" ]; then
+  export CITY="$2"
+fi
+if [ -n "${3-}" ]; then
+  export BBOX="$3"
+elif [ -n "${CITY-}" ]; then
+  export BBOX="$(python3 -c 'import subway_structure; c = [x for x in subway_structure.download_cities() if x.name == "'$CITY'"]; print("{1},{0},{3},{2}".format(*c[0].bbox))')" || true
+fi
+"$(dirname "$0")/process_subways.sh" "$1"