diff --git a/Makefile b/Makefile
index 2671b95..02872a1 100644
--- a/Makefile
+++ b/Makefile
@@ -18,7 +18,7 @@ OSM_NAME_COLUMN?=name
 OSM_SRID?=3857
 OSM_UNITS?=meters
 OSM_DB_CONNECTION?=host=localhost dbname=osm user=osm password=osm port=5432
-OSM_EXTENT=-20000000 -20000000 20000000 20000000
+OSM_EXTENT?=-20000000 -20000000 20000000 20000000
 OSM_WMS_SRS?=EPSG:900913 EPSG:4326 EPSG:3857 EPSG:2154 EPSG:310642901 EPSG:4171 EPSG:310024802 EPSG:310915814 EPSG:310486805 EPSG:310702807 EPSG:310700806 EPSG:310547809 EPSG:310706808 EPSG:310642810 EPSG:310642801 EPSG:310642812 EPSG:310032811 EPSG:310642813 EPSG:2986
 DEBUG?=1
 LAYERDEBUG?=1