The datasets in this series represent the Countryside Information System (CIS) and contain habitat and landscape information and a wide range of environmental data, including landscape features, vegetation habitats and topography. The CIS can be linked to kilometre resolution grid references and stored, manipulated and presented in graphical and tabular format. The Ordnance Survey and Ordnance Survey of Northern Ireland grid reference systems mean that CIS runs in two modes, one to describe Great Britain, the other Northern Ireland (NI). Both modes are components of the standard system.
CIS handles three types of data: census, sample and region.
A census dataset stores one value for every land square that has data. The values stored for each square may be either numerical values (such as area of deciduous woodland or mean summer temperature) or attributes (such as name of predominant county).
A sample dataset also supplies a value for every land square that has data, but the values are calculated from sampled data. A special census file called a landclass file is created that allocates one of up to 80 landclasses to every land square and also optionally indicates the applicable area on every land square. The sampled data then consists only of one value for each of the landclasses - a maximum of 80 different values, depending on the exact classification used. CIS calculates the value applicable for each square as it is needed.
Finally, a CIS region is merely a set of land squares. For example, a region may consist of all the squares containing Sites of Special Scientific Interest (SSSIs), all the squares with more than 90% urban cover, all the squares with a mean altitude over 500m and so on. A region file holds a single region.
One of the important features of the CIS is its ability to handle sample information using stratification. The system is supplied with data collected using the Institute of Terrestrial Ecology (ITE) Land Classification and the Northern Ireland (NI) Land Classification, but it can be used with any classification that divides the kilometre cells into different strata. The stratifications need not be complete, but only cover the region of interest, so for example a classification for Wales can be derived and used in the system.
The datasets in this series are available to download. Links to individual datasets can be found at piece level.