readers' comments

p.36 – corrected paragraph on deriving coordinates from the city plans:

Deriving coordinates from the grid shown on the city plans is not as straightforward as it might seem. Coordinates on maps are conventionally called Eastings and Northings (these are measured along the X- and Y-axes, west to east and south to north respectively). The Northing figure on the Soviet plans is the number of kilometers from the equator (e.g. 6050 in the northeast corner of the plan of Darlington in fig 2.24), while the Easting figure is a composite of a zone number and a distance. The first one or two digits of the Easting refer to the number of the zone counted east from the Greenwich meridian (which is different from the standard G-K numbering), so that zone 1 is 0° to 6°E, zone 2 is 6°E to 12°E and so on, around to zone 60, which is 6°W to 0°. The last three digits of the Easting refer to the number of kilometers east from the 'false meridian' (introduced to avoid negative coordinates), which is located 500 km west from the principal meridian of the map zone (i.e. 3°W for the zone M-30). The number 60607 in the NW corner of the plan of Southampton therefore means that the point is located in zone 60 (G-K zone 30), at a distance of 107 km (607 - 500) to the east from the principal meridian (3°W for this zone). The number 1384 in the NW corner of the plan of Dover means that the point is located in zone 1 (G-K zone 31) at a distance of 116 km (384 - 500) to the west from the principal meridian (3°E for this zone).

Charles Aylmer, emails 24 Oct and 25 Oct, 2017
I've checked the Beijing 1:25,000 town plan and objective 181 is listed as "Sobranie narodnykh predstavitelei vsekitaiskoe" i.e. National People's Congress, which is the body that convenes in the Great Hall of the People. I don't know where the alleged misattribution you cite has come from.
p. 49: Schischova > Shishova, Olienikova > Oleinikova, Schlyago > Shlyago
p. 89: Flughaven > Flughafen
p. 127: Lomondsov > Lomonosov
p. 138: Militärtopographicgraphischer > Militärtopographischer
p. 215: [a] > a

Bernard Anderson, email 23 Oct
I fully appreciate the particular interest there is in the City plans, so I would not quibble too much about the decision to focus on larger scale mapping in preference to the 1:50 000 and 1:100 0000, although personally I think these are equally fascinating. Like the large scale plans these also include items which were deleted for security reasons from OS maps – the two naval depots on the Stour Estuary in North Essex for instance.
One possible error, plate A1.14. I have a copy of the Liverpool Sheets and these were among those rapidly extracted for further inspection. You are correct about the date for the closure of the Liverpool Overhead Railway, however, directly beneath this and running for almost the entire length of the dock estate was another set of tracks belonging to the Mersey Dock Board, these remained in situ and in some places in use into the early 1970s. They were far less prominent and as they only carried freight traffic were less well known. When I moved to Liverpool in 1975 they were no longer in use but still there, the parallel road was crossed at numerous points by links between them and the national network as is shown on the plan. Not on your chosen extract but on the original, there is an error at the northern end as it does show the original Seaforth Station of the Overhead but that had certainly gone by the time I lived in the area. Interestingly, the same error is present on my A-Z streetmap.