SK-42 Topos

The topographic maps or ‘topos’ are non-rectangular sheets based on sheet lines defined by lines of latitude and longitude and numbered in accordance with the nomenclature devised for the International Map of the World. Topos were produced at seven scales, classified by the Soviet authorities as:
• Small-scale / general terrain evaluation: 1:1,000,000
• Small-scale / operational: 1:500,000
• Medium-scale / operational-tactical: 1:200,000
• Medium-scale / tactical: 1:100,000
• Large-scale / tactical: 1:50,000, 1:25,000, 1:10,000

The security classifications of the topographic maps are in general as follows:
• Small-scale sheets are unclassified
• 1:200,000 scale maps are labelled Для Служебного Пользования (For Official Use)
• 1:100,000 and 1:50,000 scale maps of USSR territory are labelled ‘Секретно’ (Secret)
• those of the rest of the world are labelled Для Служебного Пользования (For Official Use)
• Larger scale topos and all city plans are labelled ‘Секретно’ (Secret).

SK-42 Topos of North America, Great Britain and other parts of the world are available to view here