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Map scales, Legends & Conventional Signs


With a paper map, the marked scale can reliably be used to measure or at least estimate a scaled distance on the map. When that map is scanned and shown on screens of various sizes at various zoom levels, that is no longer possible; the true scale aspect has been lost.

The real importance of retaining the map scale in the metadata for the map is to determine the level of detail.
It has long been a cartographer's dilemma, how much data to include on a map? Too much and it becomes cluttered, too little and it loses the point of producing it so all maps are a compromise between those opposing requirements.

Large scale maps show a lot of detail, the standard Great War large scale map was the 1:10,000 series, known as large scale because its representative fraction (RF), 1/10,000, is larger than the RF of a small scale map such as the 1:1,000,000 series whose RF is 1/1,000,000. Many of these 1:10,000 maps had the term Trench Map printed on the cover, a term that is not defined for 1:10,000 maps but is the most common in general usage. Some 1:20,000 maps had the same description whilst very few 1:40,000 maps shewed trenches in any detail. Smaller scale maps sometimes show just the front line.

Many 1:10,000 trench maps were produced photographically from 1:20,000 maps and vice versa, where this is true the map detail is identical.

See page on this map collection.

Map legends, also known as Conventional Signs

British including those for attack, defence and situation maps

German and French from US sources

German as employed on the Siegfried Line. Issued by Second German Army in the Spring of 1917

German signs from captured maps and documents

French when different from British

Conventional signs for map illustration (Includes British and German Siegried Line and French mapping symbols

Turkish including those on Şevki Paşa post evacuation maps





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