Principles of digital topographic map classification

In order not to be puzzled with a great variety of digital topographic maps, it is necessary to classify them, i.e. divide digital topographic maps into groups (sorts) according to some characteristics and features. Scientific classification of topographic maps facilitates the study of characteristics and features peculiar to distinct digital topographic maps, contributes to organization of cartographic manufacture, is necessary for digital topographic maps cataloging, systematic placing and finally, what is especially important is that scientific classification of topographic maps facilitates the search, distribution and download of necessary maps. Strict classification is a necessary condition for introduction of cartographic service automatization.

Possible criteria of digital topographic maps classification

Digital topographic maps can be distinguished or classified according to several criteria: scale, land coverage, subject (i.e. subject of content), purpose, mathematical basis, time, language, etc. The most significant are the first four mentioned criteria, which determine topographic map content and nature. Digital topographic maps classification according to other criteria is subsidiary; it can be applied in some specific needs. For example, digital topographic maps classification according to the time of issue is of great importance for historical maps storing.

Scientific topographic maps classification

Every scientific topographic maps classification should meet necessary logical conditions. First of all, sequence of passing from more general notion (e.g. class) to some more particular (subclass, sort, genus), i.e. course of general notion division into peculiar parts. For example, all topographic maps are divided into geographical and subject, but it wouldn’t be right to divide all digital topographic maps into geographical, subject and geological, because the last represent one sort of topographic map of nature phenomena, which in its turn is a class of subject maps. Secondly, in every stage of digital topographic map classification it is necessary to apply certain basis of division. For instance, it is known that geographical maps are divided into survey, survey-topographic, and topographic according to scale. It would be unreasonable to classify geographical maps into survey, survey-topographic, topographic, and educational, because two principles are used: scale and purpose. It is obvious that among educational maps, maps of any scale can be found, including survey and topographic one. It is quite sensible to use one criterion (e.g. subject of content) as a principle of division of all maps at all stages of classification. But this requirement doesn’t exclude the possibility of additional further internal division according to other principles, e.g. singling out educational maps among geographical one. What is more, it is necessary to bear in mind, that while dividing a general notion into some more peculiar the sum of the last must be equal to the general notion. For example, the division of geologic maps in to two groups - stratigraphic and tectonic is not enough, because these two groups do not comprise all the diversity of geologic maps that also include maps of overburden, hydrogeologic maps, maps of minerals, etc.

Groups singled out at every stage of classification, must be easily distinguished in order to avoid rating of one and the same map to different classes. The more unsystematic the classification is the harder is to apply it in practice.

Map storages, collecting all kinds of cartographic material, are primarily subdivided according to the form of cartographic material, where we are sure to find geographical maps, atlases, relief maps, globes, etc. In institutions dealing with cartography, that collect also textual sources, it is necessary to have separate place for geographical catalogues, instructions and specifications, sailing directions and other specific material, such as statistics, etc. Special place should also be provided for digital maps.

It is obvious that classification of digital topographic maps is changing and improving alongside with development of cartography. It is very important that classification of digital topographic maps reflects all the changes in classes, types, kind of maps without fundamental breaking of its structure.