That special air maps might be necessary was realised as long ago as 1909 when the use of maps in connection with balloons was being discussed: but there was little progress and Bleriot's flight in the same year imposed a completely new outlook. At first, with the air speeds common in the early days, it was possible for the aviator to use standard topographical maps on scales such as half or one inch to one mile and navigate by the identification of prominent landmarks. It was soon realised however that certain features were more outstanding than others and this observation was incorporated in one of the very first attempts to produce an "aero" map made in 1912. In this the roads, railways and lakes were emphasised by hand colouring on a photoprint of the one inch Ordnance Survey sheet. The practice of using, or hand amending, existing topographical maps continued in the early days of the 1914-18 war but the growth of the R.F.C. and the R.N.A.S. emphasised the need for specific air maps. By the end of the war the R.N.A.S. had special air charts for use over the coastal areas of the British Isles, and a special aviation map of France had been produced for the R.F.C. These maps were probably the first ever made in quantity for use in the air but they did not differ radically from the existing topographical series except in the simplification of certain detail and the showing of additional data of value to the airman -aerodrolnes, landing grounds, dangers etc. Air speeds were still not very high and flying was largely confined to fine weather so that the main form of navigation continued to be by the direct reading of maps.
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