Editing Geographers' A–Z Street Atlas (section)

==Dating old maps==
[[File:Geographers London Map 1957 Cover.jpg|thumb|right|upright|The cover of the ''Authentic Map of London'' of 1957]]
Until relatively recently,{{when|date=July 2021}} maps produced by the Geographers' (A–Z) Map Company did not include a publication date. It is possible to determine a date range for publication due to the following:
* their first map was published in 1936;
* the only maps produced by them during [[World War II]] (1939–1945) were war maps of Europe;
* until his death in 1958, the front cover stated "Produced under the direction of Alexander Gross";<ref name="Berthoud">{{cite web |last1=Berthoud |first1=Peter |title=The Real Story of A-Z Maps by Phyllis Pearsall |url=https://www.peterberthoud.co.uk/post/the-real-story-of-a-z-maps-by-phyllis-pearsall |website=Peter Berthoud |access-date=12 February 2025 |language=en |date=19 May 2014}}</ref>
* until 1962, the publication address was "28 [[Gray's Inn Road]], [[Holborn]], London";
* from 1962 to 1992, the publication address was "[[Sevenoaks]], Kent";
* in 1972, the company name was changed from "Geographers' Map Company" to "Geographers' A–Z Map Company";
* from 1992 to 2019, the publication address is "[[Borough Green]], Kent".

===Date codes===
On all A–Z maps, there is a three or four letter code in one of the corners, often the one containing the key. These letters represent numbers, which are the cartographic date, in the form (M)MYY. There was at least one scheme used, and perhaps a second.

In one scheme, the letters JIHGFEDCBA represent the digits 1 to 9 and 0, so that HFD would be 357, indicating a publication date of March 1957.<ref>{{cite web |last1=Dyke |first1=Kevin |last2=Hoehn |first2=Phil |last3=Zellmer |first3=Linda |title=Date Codes for Maps |url=https://waml.org/resources/toolbox/maps/date-codes-for-maps/#articleTOC_7 |website=Western Association of Map Libraries |access-date=12 February 2025 |date=February 26, 2024}} Source: ''Biblio'' (University of Illinois Map and Geography Library), 1987-1.</ref> This seems to have been used on all the company's folding maps, and possibly also those in book form.

If a second scheme was used, if might have been that of [[Geographia Map Company]], also founded by Alexander Gross. In that case, the letters CUMBERLAND represent the digits 1 to 9 and 0.<ref>{{cite web |last1=Dyke |first1=Kevin |last2=Hoehn |first2=Phil |last3=Zellmer |first3=Linda |title=Date Codes for Maps |url=https://waml.org/resources/toolbox/maps/date-codes-for-maps/#articleTOC_8 |website=Western Association of Map Libraries |access-date=12 February 2025 |date=February 26, 2024}} Source: {{cite journal |title=Geographia Date Codes |journal=Bulletin - Association of Canadian Map Libraries and Archives |date=1981 |issue=40 |page=57 |url=https://openjournals.uwaterloo.ca/index.php/acmla/issue/view/84/95 |format=pdf}}</ref>