[Talk-GB] Holes in modern England?

[Martin Wynne]

I think I have now worked this out.

The NLS historic 25" georeferenced map first looks on the server for 
tiles from the County Series maps.

If that returns a 404 Not Found error (presumably because the sheet 
wasn't available when the rest were scanned), it then looks on the 
server for the same tile from the "Holes England" map to fill in the gap.

These appear to be from later OS revisions, but are available only for 
the locations shown as blank patches at:

 
https://geo.nls.uk/mapdata3/os/25_inch/holes_england/#holes_england_new/ol3

Hopefully if/when they get enough of these scans, these later 25" 
revisions will become available as a separate map on the web site.

cheers,

Martin.