A map series is a group of topographic or thematic charts or maps usually having the same scale and cartographic specifications, and with each sheet appropriately identified by its publisher as belonging to the same series.
Map series occur when an area is to be covered by a map that, due to its scale, must be spread over several sheets. Nevertheless, the individual sheets of a map series can also be used quite independently, as they generally have full map surround details and legends. If a publisher produces several map series at different scales, for instance 1:25,000, 1:50,000 and 1:100,000, then these series are called scale series.
According to 2007/2/EC European directive, national mapping agencies of European Union countries must have publicly available services for searching, viewing and downloading their official map series. Maps produced by some of them are available under a free license that allows re-use, such as a Creative Commons license.
The concept of a map series
In everyday use, individual maps and atlases are sometimes described as being part of a "map series". However, that is not a correct use of the technical language of cartography, in which the term map series refers exclusively to the phenomenon described here, namely a map published over several sheets. The scope of a map series can range from as few as two sheets to at least tens of thousands of sheets.
Obsolete maps, especially of the 19th century, are often named Topographic Atlases, because their small-sized sheets were also bound into atlases. An example of such a map series is the Topographic Atlas of the Kingdom of Hanover and the Duchy of Brunswick.
A map series is not to be confused with a map collection, which is a map storage site and its contents, usually forming part of a library, archive, museum, or held at the premises of a map publisher or public authority.
Publication forms
It is technically very difficult, and it would be highly impractical, to print, e.g., the National Map of Switzerland on a single sheet at a scale of 1:25,000 (that particular map would be about high and wide). For that reason, map series are issued and preserved in loose-leaf form. In extreme cases, a map series can include thousands of sheets. Probably the greatest map series ever created is the 1:25,000 topographic map of the Soviet Union, with about 300,000 sheets, completed in 1987.
Occasionally, smaller map series will be compiled by the buyer into a bound volume, without thereby incorporating into the bound work the otherwise typical features of an atlas.
The sheets of a map series can also be glued by the buyer to their neighbouring sheets, especially as a wall decoration. So, for example, the National Map of Switzerland (1:100,000), which consists of 22 sheets, can be seen as a wall decoration in the Federal Palace of Switzerland and in the Swiss National Library.
Features
Map series are divided into particular systems of single sheets named and numbered according to common principles. Thus, the characteristics of a particular sheet in a map series apply equally to all the other sheets of the map series. So, for example, all sheets normally have the same cartographic projections, geodetic datums, scale, and a uniform content and cartographic design.
Sheet network designs
Theoretically, almost any sheet network design can be used. In practice, variants of the mercator projection are the most widely used today, frequently in conjunction with the UTM coordinate system.
Organization
All sheets of a map series are created in the same way. Thus, they bear all of the common map series titles, have the same author and copyright notices, use the same map legend and, with the exception of any possible edge sheets, are usually printed on paper of a uniform size. An individual sheet's title and number identifies and locates that sheet's place in the map series.
Nature of the sheet divisions
The sheets are divided from each other either square to the map grid, or along the meridians and parallels. In the first case, the sheets will all be the same size. In the second case, the sheet size will decrease towards the north (for a northern hemisphere map) or the south (for a southern hemisphere map).
Regardless of the selected type of division, there is a convention that four sheets of a particular scale map are used to depict the same area as one sheet of the next smaller scale map series produced by the same publisher.