+
+imagery_layer "gb_os_sv_2016_04" do
+ site "os.openstreetmap.org"
+ title "April 2016"
+ default_layer true
+ projection "EPSG:27700"
+ source "/data/imagery/gb/os-sv/ossv-2016-04-combined.vrt"
+ copyright "Contains Ordnance Survey data © Crown copyright and database right 2016"
+ background_colour "230 246 255" # OSSV Water Blue
+ extension "os_sv_png"
+ url_aliases ["/sv-2016-04", "/sv"] # Add "/sv" to current edition for backward compatibility
+end
+
+# Diff layers
+imagery_layer "gb_os_sv_diff_2010_04_2010_11" do
+ site "os.openstreetmap.org"
+ projection "EPSG:27700"
+ source "/data/imagery/gb/os-sv/ossv-diff-2010-04-2010-11-combined.vrt"
+ copyright "Contains Ordnance Survey data © Crown copyright and database right 2010"
+ extension "os_sv_diff_png"
+ url_aliases ["/sv-diff-2010-04-2010-11"]
+ overlay true
+ revision 2
+end
+
+imagery_layer "gb_os_sv_diff_2010_04_2011_05" do
+ site "os.openstreetmap.org"
+ projection "EPSG:27700"
+ source "/data/imagery/gb/os-sv/ossv-diff-2010-04-2011-05-combined.vrt"
+ copyright "Contains Ordnance Survey data © Crown copyright and database right 2011"
+ extension "os_sv_diff_png"
+ url_aliases ["/sv-diff-2010-04-2011-05"]
+ overlay true
+ revision 2
+end
+
+imagery_layer "gb_os_sv_diff_2010_04_2011_11" do
+ site "os.openstreetmap.org"
+ projection "EPSG:27700"
+ source "/data/imagery/gb/os-sv/ossv-diff-2010-04-2011-11-combined.vrt"
+ copyright "Contains Ordnance Survey data © Crown copyright and database right 2011"
+ extension "os_sv_diff_png"
+ url_aliases ["/sv-diff-2010-04-2011-11"]
+ overlay true
+ revision 2
+end
+
+imagery_layer "gb_os_sv_diff_2010_04_2012_05" do
+ site "os.openstreetmap.org"
+ projection "EPSG:27700"
+ source "/data/imagery/gb/os-sv/ossv-diff-2010-04-2012-05-combined.vrt"
+ copyright "Contains Ordnance Survey data © Crown copyright and database right 2012"
+ extension "os_sv_diff_png"
+ url_aliases ["/sv-diff-2010-04-2012-05"]
+ overlay true
+ revision 2
+end
+
+imagery_layer "gb_os_sv_diff_2010_04_2012_11" do
+ site "os.openstreetmap.org"
+ projection "EPSG:27700"
+ source "/data/imagery/gb/os-sv/ossv-diff-2010-04-2012-11-combined.vrt"
+ copyright "Contains Ordnance Survey data © Crown copyright and database right 2012"
+ extension "os_sv_diff_png"
+ url_aliases ["/sv-diff-2010-04-2012-11"]
+ overlay true
+ revision 1
+end
+
+imagery_layer "gb_os_sv_diff_2010_04_2013_05" do
+ site "os.openstreetmap.org"
+ projection "EPSG:27700"
+ source "/data/imagery/gb/os-sv/ossv-diff-2010-04-2013-05-combined.vrt"
+ copyright "Contains Ordnance Survey data © Crown copyright and database right 2013"
+ extension "os_sv_diff_png"
+ url_aliases ["/sv-diff-2010-04-2013-05"]
+ overlay true
+ revision 1
+end
+
+imagery_layer "gb_os_sv_diff_2010_04_2013_11" do
+ site "os.openstreetmap.org"
+ projection "EPSG:27700"
+ source "/data/imagery/gb/os-sv/ossv-diff-2010-04-2013-11-combined.vrt"
+ copyright "Contains Ordnance Survey data © Crown copyright and database right 2013"
+ extension "os_sv_diff_png"
+ url_aliases ["/sv-diff-2010-04-2013-11"]
+ overlay true
+ revision 1
+end
+
+imagery_layer "gb_os_sv_diff_2010_04_2014_04" do
+ site "os.openstreetmap.org"
+ projection "EPSG:27700"
+ source "/data/imagery/gb/os-sv/ossv-diff-2010-04-2014-04-combined.vrt"
+ copyright "Contains Ordnance Survey data © Crown copyright and database right 2014"
+ extension "os_sv_diff_png"
+ url_aliases ["/sv-diff-2010-04-2014-04"]
+ overlay true
+end
+
+# imagery_layer "gb_os_sv_diff_2010_04_2014_10" do
+# site "os.openstreetmap.org"
+# projection "EPSG:27700"
+# source "/data/imagery/gb/os-sv/ossv-diff-2010-04-2014-10-combined.vrt"
+# copyright "Contains Ordnance Survey data © Crown copyright and database right 2014"
+# extension "os_sv_diff_png"
+# url_aliases ["/sv-diff-2010-04-2014-10"]
+# overlay true
+# end
+#
+# imagery_layer "gb_os_sv_diff_2010_04_2015_05" do
+# site "os.openstreetmap.org"
+# projection "EPSG:27700"
+# source "/data/imagery/gb/os-sv/ossv-diff-2010-04-2015-05-combined.vrt"
+# copyright "Contains Ordnance Survey data © Crown copyright and database right 2015"
+# extension "os_sv_diff_png"
+# url_aliases ["/sv-diff-2010-04-2015-05"]
+# overlay true
+# end
+#
+# imagery_layer "gb_os_sv_diff_2010_04_2015_11" do
+# site "os.openstreetmap.org"
+# projection "EPSG:27700"
+# source "/data/imagery/gb/os-sv/ossv-diff-2010-04-2015-11-combined.vrt"
+# copyright "Contains Ordnance Survey data © Crown copyright and database right 2015"
+# extension "os_sv_diff_png"
+# url_aliases ["/sv-diff-2010-04-2015-11"]
+# overlay true
+# end
+#
+# imagery_layer "gb_os_sv_diff_2010_04_2016_04" do
+# site "os.openstreetmap.org"
+# projection "EPSG:27700"
+# source "/data/imagery/gb/os-sv/ossv-diff-2010-04-2016-04-combined.vrt"
+# copyright "Contains Ordnance Survey data © Crown copyright and database right 2016"
+# extension "os_sv_diff_png"
+# url_aliases ["/sv-diff-2010-04-2016-04"]
+# overlay true
+# end
+#
+# imagery_layer "gb_os_sv_diff_2010_11_2011_05" do
+# site "os.openstreetmap.org"
+# projection "EPSG:27700"
+# source "/data/imagery/gb/os-sv/ossv-diff-2010-11-2011-05-combined.vrt"
+# copyright "Contains Ordnance Survey data © Crown copyright and database right 2011"
+# extension "os_sv_diff_png"
+# url_aliases ["/sv-diff-2010-11-2011-05"]
+# overlay true
+# end
+#
+# imagery_layer "gb_os_sv_diff_2010_11_2011_11" do
+# site "os.openstreetmap.org"
+# projection "EPSG:27700"
+# source "/data/imagery/gb/os-sv/ossv-diff-2010-11-2011-11-combined.vrt"
+# copyright "Contains Ordnance Survey data © Crown copyright and database right 2011"
+# extension "os_sv_diff_png"
+# url_aliases ["/sv-diff-2010-11-2011-11"]
+# overlay true
+# end
+#
+# imagery_layer "gb_os_sv_diff_2010_11_2012_05" do
+# site "os.openstreetmap.org"
+# projection "EPSG:27700"
+# source "/data/imagery/gb/os-sv/ossv-diff-2010-11-2012-05-combined.vrt"
+# copyright "Contains Ordnance Survey data © Crown copyright and database right 2012"
+# extension "os_sv_diff_png"
+# url_aliases ["/sv-diff-2010-11-2012-05"]
+# overlay true
+# end
+#
+# imagery_layer "gb_os_sv_diff_2010_11_2012_11" do
+# site "os.openstreetmap.org"
+# projection "EPSG:27700"
+# source "/data/imagery/gb/os-sv/ossv-diff-2010-11-2012-11-combined.vrt"
+# copyright "Contains Ordnance Survey data © Crown copyright and database right 2012"
+# extension "os_sv_diff_png"
+# url_aliases ["/sv-diff-2010-11-2012-11"]
+# overlay true
+# end
+#
+# imagery_layer "gb_os_sv_diff_2010_11_2013_05" do
+# site "os.openstreetmap.org"
+# projection "EPSG:27700"
+# source "/data/imagery/gb/os-sv/ossv-diff-2010-11-2013-05-combined.vrt"
+# copyright "Contains Ordnance Survey data © Crown copyright and database right 2013"
+# extension "os_sv_diff_png"
+# url_aliases ["/sv-diff-2010-11-2013-05"]
+# overlay true
+# end
+#
+# imagery_layer "gb_os_sv_diff_2010_11_2013_11" do
+# site "os.openstreetmap.org"
+# projection "EPSG:27700"
+# source "/data/imagery/gb/os-sv/ossv-diff-2010-11-2013-11-combined.vrt"
+# copyright "Contains Ordnance Survey data © Crown copyright and database right 2013"
+# extension "os_sv_diff_png"
+# url_aliases ["/sv-diff-2010-11-2013-11"]
+# overlay true
+# end
+#
+# imagery_layer "gb_os_sv_diff_2010_11_2014_04" do
+# site "os.openstreetmap.org"
+# projection "EPSG:27700"
+# source "/data/imagery/gb/os-sv/ossv-diff-2010-11-2014-04-combined.vrt"
+# copyright "Contains Ordnance Survey data © Crown copyright and database right 2014"
+# extension "os_sv_diff_png"
+# url_aliases ["/sv-diff-2010-11-2014-04"]
+# overlay true
+# end
+#
+# imagery_layer "gb_os_sv_diff_2010_11_2014_10" do
+# site "os.openstreetmap.org"
+# projection "EPSG:27700"
+# source "/data/imagery/gb/os-sv/ossv-diff-2010-11-2014-10-combined.vrt"
+# copyright "Contains Ordnance Survey data © Crown copyright and database right 2014"
+# extension "os_sv_diff_png"
+# url_aliases ["/sv-diff-2010-11-2014-10"]
+# overlay true
+# end
+#
+# imagery_layer "gb_os_sv_diff_2010_11_2015_05" do
+# site "os.openstreetmap.org"
+# projection "EPSG:27700"
+# source "/data/imagery/gb/os-sv/ossv-diff-2010-11-2015-05-combined.vrt"
+# copyright "Contains Ordnance Survey data © Crown copyright and database right 2015"
+# extension "os_sv_diff_png"
+# url_aliases ["/sv-diff-2010-11-2015-05"]
+# overlay true
+# end
+#
+# imagery_layer "gb_os_sv_diff_2010_11_2015_11" do
+# site "os.openstreetmap.org"
+# projection "EPSG:27700"
+# source "/data/imagery/gb/os-sv/ossv-diff-2010-11-2015-11-combined.vrt"
+# copyright "Contains Ordnance Survey data © Crown copyright and database right 2015"
+# extension "os_sv_diff_png"
+# url_aliases ["/sv-diff-2010-11-2015-11"]
+# overlay true
+# end
+#
+# imagery_layer "gb_os_sv_diff_2010_11_2016_04" do
+# site "os.openstreetmap.org"
+# projection "EPSG:27700"
+# source "/data/imagery/gb/os-sv/ossv-diff-2010-11-2016-04-combined.vrt"
+# copyright "Contains Ordnance Survey data © Crown copyright and database right 2016"
+# extension "os_sv_diff_png"
+# url_aliases ["/sv-diff-2010-11-2016-04"]
+# overlay true
+# end
+#
+# imagery_layer "gb_os_sv_diff_2011_05_2011_11" do
+# site "os.openstreetmap.org"
+# projection "EPSG:27700"
+# source "/data/imagery/gb/os-sv/ossv-diff-2011-05-2011-11-combined.vrt"
+# copyright "Contains Ordnance Survey data © Crown copyright and database right 2011"
+# extension "os_sv_diff_png"
+# url_aliases ["/sv-diff-2011-05-2011-11"]
+# overlay true
+# end
+#
+# imagery_layer "gb_os_sv_diff_2011_05_2012_05" do
+# site "os.openstreetmap.org"
+# projection "EPSG:27700"
+# source "/data/imagery/gb/os-sv/ossv-diff-2011-05-2012-05-combined.vrt"
+# copyright "Contains Ordnance Survey data © Crown copyright and database right 2012"
+# extension "os_sv_diff_png"
+# url_aliases ["/sv-diff-2011-05-2012-05"]
+# overlay true
+# end
+#
+# imagery_layer "gb_os_sv_diff_2011_05_2012_11" do
+# site "os.openstreetmap.org"
+# projection "EPSG:27700"
+# source "/data/imagery/gb/os-sv/ossv-diff-2011-05-2012-11-combined.vrt"
+# copyright "Contains Ordnance Survey data © Crown copyright and database right 2012"
+# extension "os_sv_diff_png"
+# url_aliases ["/sv-diff-2011-05-2012-11"]
+# overlay true
+# end
+#
+# imagery_layer "gb_os_sv_diff_2011_05_2013_05" do
+# site "os.openstreetmap.org"
+# projection "EPSG:27700"
+# source "/data/imagery/gb/os-sv/ossv-diff-2011-05-2013-05-combined.vrt"
+# copyright "Contains Ordnance Survey data © Crown copyright and database right 2013"
+# extension "os_sv_diff_png"
+# url_aliases ["/sv-diff-2011-05-2013-05"]
+# overlay true
+# end
+#
+# imagery_layer "gb_os_sv_diff_2011_05_2013_11" do
+# site "os.openstreetmap.org"
+# projection "EPSG:27700"
+# source "/data/imagery/gb/os-sv/ossv-diff-2011-05-2013-11-combined.vrt"
+# copyright "Contains Ordnance Survey data © Crown copyright and database right 2013"
+# extension "os_sv_diff_png"
+# url_aliases ["/sv-diff-2011-05-2013-11"]
+# overlay true
+# end
+#
+# imagery_layer "gb_os_sv_diff_2011_05_2014_04" do
+# site "os.openstreetmap.org"
+# projection "EPSG:27700"
+# source "/data/imagery/gb/os-sv/ossv-diff-2011-05-2014-04-combined.vrt"
+# copyright "Contains Ordnance Survey data © Crown copyright and database right 2014"
+# extension "os_sv_diff_png"
+# url_aliases ["/sv-diff-2011-05-2014-04"]
+# overlay true
+# end
+#
+# imagery_layer "gb_os_sv_diff_2011_05_2014_10" do
+# site "os.openstreetmap.org"
+# projection "EPSG:27700"
+# source "/data/imagery/gb/os-sv/ossv-diff-2011-05-2014-10-combined.vrt"
+# copyright "Contains Ordnance Survey data © Crown copyright and database right 2014"
+# extension "os_sv_diff_png"
+# url_aliases ["/sv-diff-2011-05-2014-10"]
+# overlay true
+# end
+#
+# imagery_layer "gb_os_sv_diff_2011_05_2015_05" do
+# site "os.openstreetmap.org"
+# projection "EPSG:27700"
+# source "/data/imagery/gb/os-sv/ossv-diff-2011-05-2015-05-combined.vrt"
+# copyright "Contains Ordnance Survey data © Crown copyright and database right 2015"
+# extension "os_sv_diff_png"
+# url_aliases ["/sv-diff-2011-05-2015-05"]
+# overlay true
+# end
+#
+# imagery_layer "gb_os_sv_diff_2011_05_2015_11" do
+# site "os.openstreetmap.org"
+# projection "EPSG:27700"
+# source "/data/imagery/gb/os-sv/ossv-diff-2011-05-2015-11-combined.vrt"
+# copyright "Contains Ordnance Survey data © Crown copyright and database right 2015"
+# extension "os_sv_diff_png"
+# url_aliases ["/sv-diff-2011-05-2015-11"]
+# overlay true
+# end
+#
+# imagery_layer "gb_os_sv_diff_2011_05_2016_04" do
+# site "os.openstreetmap.org"
+# projection "EPSG:27700"
+# source "/data/imagery/gb/os-sv/ossv-diff-2011-05-2016-04-combined.vrt"
+# copyright "Contains Ordnance Survey data © Crown copyright and database right 2016"
+# extension "os_sv_diff_png"
+# url_aliases ["/sv-diff-2011-05-2016-04"]
+# overlay true
+# end
+#
+# imagery_layer "gb_os_sv_diff_2011_11_2012_05" do
+# site "os.openstreetmap.org"
+# projection "EPSG:27700"
+# source "/data/imagery/gb/os-sv/ossv-diff-2011-11-2012-05-combined.vrt"
+# copyright "Contains Ordnance Survey data © Crown copyright and database right 2012"
+# extension "os_sv_diff_png"
+# url_aliases ["/sv-diff-2011-11-2012-05"]
+# overlay true
+# end
+#
+# imagery_layer "gb_os_sv_diff_2011_11_2012_11" do
+# site "os.openstreetmap.org"
+# projection "EPSG:27700"
+# source "/data/imagery/gb/os-sv/ossv-diff-2011-11-2012-11-combined.vrt"
+# copyright "Contains Ordnance Survey data © Crown copyright and database right 2012"
+# extension "os_sv_diff_png"
+# url_aliases ["/sv-diff-2011-11-2012-11"]
+# overlay true
+# end
+#
+# imagery_layer "gb_os_sv_diff_2011_11_2013_05" do
+# site "os.openstreetmap.org"
+# projection "EPSG:27700"
+# source "/data/imagery/gb/os-sv/ossv-diff-2011-11-2013-05-combined.vrt"
+# copyright "Contains Ordnance Survey data © Crown copyright and database right 2013"
+# extension "os_sv_diff_png"
+# url_aliases ["/sv-diff-2011-11-2013-05"]
+# overlay true
+# end
+#
+# imagery_layer "gb_os_sv_diff_2011_11_2013_11" do
+# site "os.openstreetmap.org"
+# projection "EPSG:27700"
+# source "/data/imagery/gb/os-sv/ossv-diff-2011-11-2013-11-combined.vrt"
+# copyright "Contains Ordnance Survey data © Crown copyright and database right 2013"
+# extension "os_sv_diff_png"
+# url_aliases ["/sv-diff-2011-11-2013-11"]
+# overlay true
+# end
+#
+# imagery_layer "gb_os_sv_diff_2011_11_2014_04" do
+# site "os.openstreetmap.org"
+# projection "EPSG:27700"
+# source "/data/imagery/gb/os-sv/ossv-diff-2011-11-2014-04-combined.vrt"
+# copyright "Contains Ordnance Survey data © Crown copyright and database right 2014"
+# extension "os_sv_diff_png"
+# url_aliases ["/sv-diff-2011-11-2014-04"]
+# overlay true
+# end
+#
+# imagery_layer "gb_os_sv_diff_2011_11_2014_10" do
+# site "os.openstreetmap.org"
+# projection "EPSG:27700"
+# source "/data/imagery/gb/os-sv/ossv-diff-2011-11-2014-10-combined.vrt"
+# copyright "Contains Ordnance Survey data © Crown copyright and database right 2011"
+# extension "os_sv_diff_png"
+# url_aliases ["/sv-diff-2011-11-2014-10"]
+# overlay true
+# end
+#
+# imagery_layer "gb_os_sv_diff_2011_11_2015_05" do
+# site "os.openstreetmap.org"
+# projection "EPSG:27700"
+# source "/data/imagery/gb/os-sv/ossv-diff-2011-11-2015-05-combined.vrt"
+# copyright "Contains Ordnance Survey data © Crown copyright and database right 2015"
+# extension "os_sv_diff_png"
+# url_aliases ["/sv-diff-2011-11-2015-05"]
+# overlay true
+# end
+#
+# imagery_layer "gb_os_sv_diff_2011_11_2015_11" do
+# site "os.openstreetmap.org"
+# projection "EPSG:27700"
+# source "/data/imagery/gb/os-sv/ossv-diff-2011-11-2015-11-combined.vrt"
+# copyright "Contains Ordnance Survey data © Crown copyright and database right 2015"
+# extension "os_sv_diff_png"
+# url_aliases ["/sv-diff-2011-11-2015-11"]
+# overlay true
+# end
+#
+# imagery_layer "gb_os_sv_diff_2011_11_2016_04" do
+# site "os.openstreetmap.org"
+# projection "EPSG:27700"
+# source "/data/imagery/gb/os-sv/ossv-diff-2011-11-2016-04-combined.vrt"
+# copyright "Contains Ordnance Survey data © Crown copyright and database right 2016"
+# extension "os_sv_diff_png"
+# url_aliases ["/sv-diff-2011-11-2016-04"]
+# overlay true
+# end
+#
+# imagery_layer "gb_os_sv_diff_2012_05_2012_11" do
+# site "os.openstreetmap.org"
+# projection "EPSG:27700"
+# source "/data/imagery/gb/os-sv/ossv-diff-2012-05-2012-11-combined.vrt"
+# copyright "Contains Ordnance Survey data © Crown copyright and database right 2012"
+# extension "os_sv_diff_png"
+# url_aliases ["/sv-diff-2012-05-2012-11"]
+# overlay true
+# end
+#
+# imagery_layer "gb_os_sv_diff_2012_05_2013_05" do
+# site "os.openstreetmap.org"
+# projection "EPSG:27700"
+# source "/data/imagery/gb/os-sv/ossv-diff-2012-05-2013-05-combined.vrt"
+# copyright "Contains Ordnance Survey data © Crown copyright and database right 2013"
+# extension "os_sv_diff_png"
+# url_aliases ["/sv-diff-2012-05-2013-05"]
+# overlay true
+# end
+#
+# imagery_layer "gb_os_sv_diff_2012_05_2013_11" do
+# site "os.openstreetmap.org"
+# projection "EPSG:27700"
+# source "/data/imagery/gb/os-sv/ossv-diff-2012-05-2013-11-combined.vrt"
+# copyright "Contains Ordnance Survey data © Crown copyright and database right 2013"
+# extension "os_sv_diff_png"
+# url_aliases ["/sv-diff-2012-05-2013-11"]
+# overlay true
+# end
+#
+# imagery_layer "gb_os_sv_diff_2012_05_2014_04" do
+# site "os.openstreetmap.org"
+# projection "EPSG:27700"
+# source "/data/imagery/gb/os-sv/ossv-diff-2012-05-2014-04-combined.vrt"
+# copyright "Contains Ordnance Survey data © Crown copyright and database right 2014"
+# extension "os_sv_diff_png"
+# url_aliases ["/sv-diff-2012-05-2014-04"]
+# overlay true
+# end
+#
+# imagery_layer "gb_os_sv_diff_2012_05_2014_10" do
+# site "os.openstreetmap.org"
+# projection "EPSG:27700"
+# source "/data/imagery/gb/os-sv/ossv-diff-2012-05-2014-10-combined.vrt"
+# copyright "Contains Ordnance Survey data © Crown copyright and database right 2014"
+# extension "os_sv_diff_png"
+# url_aliases ["/sv-diff-2012-05-2014-10"]
+# overlay true
+# end
+#
+# imagery_layer "gb_os_sv_diff_2012_05_2015_05" do
+# site "os.openstreetmap.org"
+# projection "EPSG:27700"
+# source "/data/imagery/gb/os-sv/ossv-diff-2012-05-2015-05-combined.vrt"
+# copyright "Contains Ordnance Survey data © Crown copyright and database right 2015"
+# extension "os_sv_diff_png"
+# url_aliases ["/sv-diff-2012-05-2015-05"]
+# overlay true
+# end
+#
+# imagery_layer "gb_os_sv_diff_2012_05_2015_11" do
+# site "os.openstreetmap.org"
+# projection "EPSG:27700"
+# source "/data/imagery/gb/os-sv/ossv-diff-2012-05-2015-11-combined.vrt"
+# copyright "Contains Ordnance Survey data © Crown copyright and database right 2015"
+# extension "os_sv_diff_png"
+# url_aliases ["/sv-diff-2012-05-2015-11"]
+# overlay true
+# end
+#
+# imagery_layer "gb_os_sv_diff_2012_05_2016_04" do
+# site "os.openstreetmap.org"
+# projection "EPSG:27700"
+# source "/data/imagery/gb/os-sv/ossv-diff-2012-05-2016-04-combined.vrt"
+# copyright "Contains Ordnance Survey data © Crown copyright and database right 2016"
+# extension "os_sv_diff_png"
+# url_aliases ["/sv-diff-2012-05-2016-04"]
+# overlay true
+# end
+#
+# imagery_layer "gb_os_sv_diff_2012_11_2013_05" do
+# site "os.openstreetmap.org"
+# projection "EPSG:27700"
+# source "/data/imagery/gb/os-sv/ossv-diff-2012-11-2013-05-combined.vrt"
+# copyright "Contains Ordnance Survey data © Crown copyright and database right 2013"
+# extension "os_sv_diff_png"
+# url_aliases ["/sv-diff-2012-11-2013-05"]
+# overlay true
+# end
+#
+# imagery_layer "gb_os_sv_diff_2012_11_2013_11" do
+# site "os.openstreetmap.org"
+# projection "EPSG:27700"
+# source "/data/imagery/gb/os-sv/ossv-diff-2012-11-2013-11-combined.vrt"
+# copyright "Contains Ordnance Survey data © Crown copyright and database right 2013"
+# extension "os_sv_diff_png"
+# url_aliases ["/sv-diff-2012-11-2013-11"]
+# overlay true
+# end
+#
+# imagery_layer "gb_os_sv_diff_2012_11_2014_04" do
+# site "os.openstreetmap.org"
+# projection "EPSG:27700"
+# source "/data/imagery/gb/os-sv/ossv-diff-2012-11-2014-04-combined.vrt"
+# copyright "Contains Ordnance Survey data © Crown copyright and database right 2014"
+# extension "os_sv_diff_png"
+# url_aliases ["/sv-diff-2012-11-2014-04"]
+# overlay true
+# end
+#
+# imagery_layer "gb_os_sv_diff_2012_11_2014_10" do
+# site "os.openstreetmap.org"
+# projection "EPSG:27700"
+# source "/data/imagery/gb/os-sv/ossv-diff-2012-11-2014-10-combined.vrt"
+# copyright "Contains Ordnance Survey data © Crown copyright and database right 2014"
+# extension "os_sv_diff_png"
+# url_aliases ["/sv-diff-2012-11-2014-10"]
+# overlay true
+# end
+#
+# imagery_layer "gb_os_sv_diff_2012_11_2015_05" do
+# site "os.openstreetmap.org"
+# projection "EPSG:27700"
+# source "/data/imagery/gb/os-sv/ossv-diff-2012-11-2015-05-combined.vrt"
+# copyright "Contains Ordnance Survey data © Crown copyright and database right 2015"
+# extension "os_sv_diff_png"
+# url_aliases ["/sv-diff-2012-11-2015-05"]
+# overlay true
+# end
+#
+# imagery_layer "gb_os_sv_diff_2012_11_2015_11" do
+# site "os.openstreetmap.org"
+# projection "EPSG:27700"
+# source "/data/imagery/gb/os-sv/ossv-diff-2012-11-2015-11-combined.vrt"
+# copyright "Contains Ordnance Survey data © Crown copyright and database right 2015"
+# extension "os_sv_diff_png"
+# url_aliases ["/sv-diff-2012-11-2015-11"]
+# overlay true
+# end
+#
+# imagery_layer "gb_os_sv_diff_2012_11_2016_04" do
+# site "os.openstreetmap.org"
+# projection "EPSG:27700"
+# source "/data/imagery/gb/os-sv/ossv-diff-2012-11-2016-04-combined.vrt"
+# copyright "Contains Ordnance Survey data © Crown copyright and database right 2016"
+# extension "os_sv_diff_png"
+# url_aliases ["/sv-diff-2012-11-2016-04"]
+# overlay true
+# end
+#
+# imagery_layer "gb_os_sv_diff_2013_05_2013_11" do
+# site "os.openstreetmap.org"
+# projection "EPSG:27700"
+# source "/data/imagery/gb/os-sv/ossv-diff-2013-05-2013-11-combined.vrt"
+# copyright "Contains Ordnance Survey data © Crown copyright and database right 2013"
+# extension "os_sv_diff_png"
+# url_aliases ["/sv-diff-2013-05-2013-11"]
+# overlay true
+# end
+#
+# imagery_layer "gb_os_sv_diff_2013_05_2014_04" do
+# site "os.openstreetmap.org"
+# projection "EPSG:27700"
+# source "/data/imagery/gb/os-sv/ossv-diff-2013-05-2014-04-combined.vrt"
+# copyright "Contains Ordnance Survey data © Crown copyright and database right 2014"
+# extension "os_sv_diff_png"
+# url_aliases ["/sv-diff-2013-05-2014-04"]
+# overlay true
+# end
+#
+# imagery_layer "gb_os_sv_diff_2013_05_2014_10" do
+# site "os.openstreetmap.org"
+# projection "EPSG:27700"
+# source "/data/imagery/gb/os-sv/ossv-diff-2013-05-2014-10-combined.vrt"
+# copyright "Contains Ordnance Survey data © Crown copyright and database right 2014"
+# extension "os_sv_diff_png"
+# url_aliases ["/sv-diff-2013-05-2014-10"]
+# overlay true
+# end
+#
+# imagery_layer "gb_os_sv_diff_2013_05_2015_05" do
+# site "os.openstreetmap.org"
+# projection "EPSG:27700"
+# source "/data/imagery/gb/os-sv/ossv-diff-2013-05-2015-05-combined.vrt"
+# copyright "Contains Ordnance Survey data © Crown copyright and database right 2015"
+# extension "os_sv_diff_png"
+# url_aliases ["/sv-diff-2013-05-2015-05"]
+# overlay true
+# end
+#
+# imagery_layer "gb_os_sv_diff_2013_05_2015_11" do
+# site "os.openstreetmap.org"
+# projection "EPSG:27700"
+# source "/data/imagery/gb/os-sv/ossv-diff-2013-05-2015-11-combined.vrt"
+# copyright "Contains Ordnance Survey data © Crown copyright and database right 2015"
+# extension "os_sv_diff_png"
+# url_aliases ["/sv-diff-2013-05-2015-11"]
+# overlay true
+# end
+#
+# imagery_layer "gb_os_sv_diff_2013_05_2016_04" do
+# site "os.openstreetmap.org"
+# projection "EPSG:27700"
+# source "/data/imagery/gb/os-sv/ossv-diff-2013-05-2016-04-combined.vrt"
+# copyright "Contains Ordnance Survey data © Crown copyright and database right 2016"
+# extension "os_sv_diff_png"
+# url_aliases ["/sv-diff-2013-05-2016-04"]
+# overlay true
+# end
+#
+# imagery_layer "gb_os_sv_diff_2013_11_2014_04" do
+# site "os.openstreetmap.org"
+# projection "EPSG:27700"
+# source "/data/imagery/gb/os-sv/ossv-diff-2013-11-2014-04-combined.vrt"
+# copyright "Contains Ordnance Survey data © Crown copyright and database right 2014"
+# extension "os_sv_diff_png"
+# url_aliases ["/sv-diff-2013-11-2014-04"]
+# overlay true
+# end
+#
+# imagery_layer "gb_os_sv_diff_2013_11_2014_10" do
+# site "os.openstreetmap.org"
+# projection "EPSG:27700"
+# source "/data/imagery/gb/os-sv/ossv-diff-2013-11-2014-10-combined.vrt"
+# copyright "Contains Ordnance Survey data © Crown copyright and database right 2014"
+# extension "os_sv_diff_png"
+# url_aliases ["/sv-diff-2013-11-2014-10"]
+# overlay true
+# end
+#
+# imagery_layer "gb_os_sv_diff_2013_11_2015_05" do
+# site "os.openstreetmap.org"
+# projection "EPSG:27700"
+# source "/data/imagery/gb/os-sv/ossv-diff-2013-11-2015-05-combined.vrt"
+# copyright "Contains Ordnance Survey data © Crown copyright and database right 2015"
+# extension "os_sv_diff_png"
+# url_aliases ["/sv-diff-2013-11-2015-05"]
+# overlay true
+# end
+#
+# imagery_layer "gb_os_sv_diff_2013_11_2015_11" do
+# site "os.openstreetmap.org"
+# projection "EPSG:27700"
+# source "/data/imagery/gb/os-sv/ossv-diff-2013-11-2015-11-combined.vrt"
+# copyright "Contains Ordnance Survey data © Crown copyright and database right 2015"
+# extension "os_sv_diff_png"
+# url_aliases ["/sv-diff-2013-11-2015-11"]
+# overlay true
+# end
+#
+# imagery_layer "gb_os_sv_diff_2013_11_2016_04" do
+# site "os.openstreetmap.org"
+# projection "EPSG:27700"
+# source "/data/imagery/gb/os-sv/ossv-diff-2013-11-2016-04-combined.vrt"
+# copyright "Contains Ordnance Survey data © Crown copyright and database right 2016"
+# extension "os_sv_diff_png"
+# url_aliases ["/sv-diff-2013-11-2016-04"]
+# overlay true
+# end
+#
+# imagery_layer "gb_os_sv_diff_2014_04_2014_10" do
+# site "os.openstreetmap.org"
+# projection "EPSG:27700"
+# source "/data/imagery/gb/os-sv/ossv-diff-2014-04-2014-10-combined.vrt"
+# copyright "Contains Ordnance Survey data © Crown copyright and database right 2014"
+# extension "os_sv_diff_png"
+# url_aliases ["/sv-diff-2014-04-2014-10"]
+# overlay true
+# end
+#
+# imagery_layer "gb_os_sv_diff_2014_04_2015_05" do
+# site "os.openstreetmap.org"
+# projection "EPSG:27700"
+# source "/data/imagery/gb/os-sv/ossv-diff-2014-04-2015-05-combined.vrt"
+# copyright "Contains Ordnance Survey data © Crown copyright and database right 2015"
+# extension "os_sv_diff_png"
+# url_aliases ["/sv-diff-2014-04-2015-05"]
+# overlay true
+# end
+#
+# imagery_layer "gb_os_sv_diff_2014_04_2015_11" do
+# site "os.openstreetmap.org"
+# projection "EPSG:27700"
+# source "/data/imagery/gb/os-sv/ossv-diff-2014-04-2015-11-combined.vrt"
+# copyright "Contains Ordnance Survey data © Crown copyright and database right 2015"
+# extension "os_sv_diff_png"
+# url_aliases ["/sv-diff-2014-04-2015-11"]
+# overlay true
+# end
+#
+# imagery_layer "gb_os_sv_diff_2014_04_2016_04" do
+# site "os.openstreetmap.org"
+# projection "EPSG:27700"
+# source "/data/imagery/gb/os-sv/ossv-diff-2014-04-2016-04-combined.vrt"
+# copyright "Contains Ordnance Survey data © Crown copyright and database right 2016"
+# extension "os_sv_diff_png"
+# url_aliases ["/sv-diff-2014-04-2016-04"]
+# overlay true
+# end
+#
+# imagery_layer "gb_os_sv_diff_2014_10_2015_05" do
+# site "os.openstreetmap.org"
+# projection "EPSG:27700"
+# source "/data/imagery/gb/os-sv/ossv-diff-2014-10-2015-05-combined.vrt"
+# copyright "Contains Ordnance Survey data © Crown copyright and database right 2015"
+# extension "os_sv_diff_png"
+# url_aliases ["/sv-diff-2014-10-2015-05"]
+# overlay true
+# end
+#
+# imagery_layer "gb_os_sv_diff_2014_10_2015_11" do
+# site "os.openstreetmap.org"
+# projection "EPSG:27700"
+# source "/data/imagery/gb/os-sv/ossv-diff-2014-10-2015-11-combined.vrt"
+# copyright "Contains Ordnance Survey data © Crown copyright and database right 2015"
+# extension "os_sv_diff_png"
+# url_aliases ["/sv-diff-2014-10-2015-11"]
+# overlay true
+# end
+#
+# imagery_layer "gb_os_sv_diff_2014_10_2016_04" do
+# site "os.openstreetmap.org"
+# projection "EPSG:27700"
+# source "/data/imagery/gb/os-sv/ossv-diff-2014-10-2016-04-combined.vrt"
+# copyright "Contains Ordnance Survey data © Crown copyright and database right 2016"
+# extension "os_sv_diff_png"
+# url_aliases ["/sv-diff-2014-10-2016-04"]
+# overlay true
+# end
+#
+# imagery_layer "gb_os_sv_diff_2015_05_2015_11" do
+# site "os.openstreetmap.org"
+# projection "EPSG:27700"
+# source "/data/imagery/gb/os-sv/ossv-diff-2015-05-2015-11-combined.vrt"
+# copyright "Contains Ordnance Survey data © Crown copyright and database right 2015"
+# extension "os_sv_diff_png"
+# url_aliases ["/sv-diff-2015-05-2015-11"]
+# overlay true
+# end
+#
+# imagery_layer "gb_os_sv_diff_2015_05_2016_04" do
+# site "os.openstreetmap.org"
+# projection "EPSG:27700"
+# source "/data/imagery/gb/os-sv/ossv-diff-2015-05-2016-04-combined.vrt"
+# copyright "Contains Ordnance Survey data © Crown copyright and database right 2016"
+# extension "os_sv_diff_png"
+# url_aliases ["/sv-diff-2015-05-2016-04"]
+# overlay true
+# end
+#
+# imagery_layer "gb_os_sv_diff_2015_11_2016_04" do
+# site "os.openstreetmap.org"
+# projection "EPSG:27700"
+# source "/data/imagery/gb/os-sv/ossv-diff-2015-11-2016-04-combined.vrt"
+# copyright "Contains Ordnance Survey data © Crown copyright and database right 2016"
+# extension "os_sv_diff_png"
+# url_aliases ["/sv-diff-2015-11-2016-04"]
+# overlay true
+# end
+#