Elevation contour lines within the Wye catchment at 10 and 20 metre intervals. The contour lines have been digitised from a scanned topographic map.

Digital river network of the natural and artificial streams and rivers within the Plynlimon catchments.

The Land Classification 1998 is a classification of Great Britain into a set of 40 environmental strata, termed land classes, to be used as a basis for ecological survey, originally developed by the Institute of Terrestrial Ecology (ITE) in the late 1970s and building upon a previous 1990 version. The strata were created from the multivariate analysis of 75 environmental variables, including climatic data, topographic data, human geographical features and geology data. The Land Classification can be used to stratify a wide range of ecological and biogeographical surveys to improve the efficiency of collection, analysis and presentation of information derived from a sample. The Land Classification 1998 provided stratification for the Countryside Survey of Great Britain 2000 and was adjusted from the 1990 version as a consequence of needing to provide National Estimates for habitats for Scotland from Countryside Survey 2000 in addition to GB as a whole. The dataset was later modified in 2007 during Countryside Survey 2007. Both the 1990 version and the 2007 version are also available. Full details about this dataset can be found at https://doi.org/10.5285/971671a6-98b4-4d80-b165-21dace7373b9

Spot heights (elevation values in metres) for areas within the Plynlimon catchments; digitised from scanned topographic maps of Plynlimon Catchment Areas.

The Land Classification 1990 is a classification of Great Britain into a set of 32 environmental strata, termed land classes, to be used as a basis for ecological survey, originally developed by the Institute of Terrestrial Ecology (ITE) in the late 1970s. The strata were created from the multivariate analysis of 75 environmental variables, including climatic data, topographic data, human geographical features and geology data. The Land Classification can be used to stratify a wide range of ecological and biogeographical surveys to improve the efficiency of collection, analysis and presentation of information derived from a sample. The Land Classification 1990 provided stratification the Countryside Survey of Great Britain 1990. The dataset was later modified in 1998 and 2007 for successive Countryside Surveys, both versions of which are also available. Full details about this dataset can be found at https://doi.org/10.5285/ab320e08-faf5-48e1-9ec9-77a213d2907f