Later in the Royal Tank Regiment his work was as a field artist to produce maps and drawings of battle zones to aid the movements of troops in difficult terrain and for aiming heavy artillery accurately.

[7] A three-man committee under Sir Sydney Oliver was set up to investigate the matter and it recognised that new leisure pursuits such as cycling and motoring would lead to a considerable demand for small-scale maps, such as 1 inch to 1 mile (1:63360).

[9] Taking the advice of his commanding officer (who possibly knew of the work of the Oliver Committee), in 1918 Martin applied for a job by submitting a watercolour and crayon design for a Christmas card – the building depicted is the headquarters of the Ordnance Survey in Southampton.

[14][4] Martin designed the cover for a 1921 official report, one copy of which was sent by the Survey's Central Bureau, led by Harold Winterbotham,[note 2] to Arthur Hinks, the rather irascible secretary of the Royal Geographical Society.

[17][18] Martin's work was primarily to create the covers for Ordnance Survey maps for which he was the person mainly responsible from 1919 to when he retired in 1940.

[21] What is often considered Martin's finest work is his 1923 painting for The Middle Thames set at Boulter's Lock at Maidenhead.

When it was succeeded by the Fifth Edition of 1931, Martin's cover showed the figure wearing a shirt with rolled-up sleeves and a slipover – but the same view.

These covers adorned the standard OS maps until the end of the Second World War and succeeded because Martin had reflected changing social attitudes.

[note 5][27] In 1969 Country Life opined[28] The picture contains six sensible people; one young hiker, three cyclists and the two locals standing outside a pub.

[31][32] The Cairngorms cover shows no people at all – to illustrate the Scots pine trees Martin decided to paint what he thought were better specimens on Southampton Common.

[33] When World War II broke out the Survey stopped producing new tourist maps and there were financial stringencies.

[34] Sven Berlin described the Ordnance Survey maps of the 1920s and 1930s as "old friends who guided you to unknown places" and John Paddy Brown wrote that "after the Second World War, the covers "were bereft of the innovation and imaginative flair which characterised the inter-War years.