Topographic Dectrac chart Northern Ireland.
Ordnance Survey of Northern Ireland.
[London] : D. Survey, Ministry of Defence United Kingdom,
1971.
Relief shown by contour lines, hypsometric tinting and spot heights.
"Decca chain 3, frequency group 3B"
Overprinted on: "the one-inch map (third series)" military ed.
Sheet 1. North Coast -- Sheet 2. Londonderry -- Sheet 3. Mid Antrim -- Sheet 4. Omagh -- Sheet 5. East Tyrone -- Sheet 6. Belfast -- Sheet 7. Enniskillin -- Sheet 8. Armagh -- Sheet 9. South Down.