How to identify a first printing
- Maps are dated by printed MARGINAL CODES: an edition letter or number, a revision/survey date, and a magnetic-variation diagram date; the marginalia is the identifier, not a copyright page.
- 19th century-1945: Old Series / New Series one-inch sheets are identified by sheet number, survey date and a printing code in the margin; reprints carry railway and road revision dates that bracket the printing.
- 1945-1970s: Seventh Series one-inch maps use an edition letter (A, B, C and so on) plus a 'fully revised' year in the lower margin to identify the printing.
- 1974-present: metric Landranger (1:50,000) and Explorer (1:25,000) sheets each carry an edition letter/number and a survey/revision year, with the credits panel listing the publication year; the latest revision year present marks the printing.
Notable points & cautions
- Identified by MARGINAL CODES (edition letter plus survey/revision year) rather than book points, the cartographic-house convention.
- Series names bracket the era: Old/New Series and the Seventh Series one-inch (pre-metric) versus Landranger/Explorer (metric, from 1974).
- The magnetic-variation diagram date is a useful internal dating clue.
- National mapping agency (founded 1791; first one-inch sheet 1801); historic county sheets are heavily collected.
Imprints
First editions also appear under: OS Landranger (1:50,000), OS Explorer / Outdoor Leisure (1:25,000), OS One-Inch / Seventh Series (historic), OS Tourist Maps. Each generally follows the house convention above.
Frequently asked questions
How do I know if my Ordnance Survey book is a first edition?
Check the copyright page. Maps are dated by printed MARGINAL CODES: an edition letter or number, a revision/survey date, and a magnetic-variation diagram date; the marginalia is the identifier, not a copyright page. 19th century-1945: Old Series / New Series one-inch sheets are identified by sheet number, survey date and a printing code in the margin; reprints carry railway and road revision dates that bracket the printing.
Does Ordnance Survey use a number line?
19th century-1945: Old Series / New Series one-inch sheets are identified by sheet number, survey date and a printing code in the margin; reprints carry railway and road revision dates that bracket the printing.
Is a book-club edition a Ordnance Survey first edition?
No. Book-club editions reprint the text but are not the true first edition. Identified by MARGINAL CODES (edition letter plus survey/revision year) rather than book points, the cartographic-house convention.
What era does this cover?
This covers Ordnance Survey (1801-present). Conventions changed over time, so confirm the era of your copy.