Common soil maps (basic maps and evaluation maps) and soil data in pedographic information systems mainly contain the regionalisation of the genetic soil type or the soil series and their associations. All information about soil characteristics are referred to mapped areas. The area content is supposed to be homogeneous. In reality the different soil characteristics (as granular soil structure, hydromorphic characteristics) are developed as a continuum without sharp boundaries. Besides there are too many blurs in the area content due to the required (discretisation) classification of the metrical soil characteristics. Therefore the practical use of common soil maps is often afflicted with problems because other spacial distribution pattern are relevant than the ones common soil maps contain for answering questions like the endanger through soil erosion.
Whereas the functional soil maps regionalise the "soil functions" or soil characteristics (as substrate distribution, development deepness (depth), water balance, erosivity). "Functional mapping" indicates the computerised models to predict the distribution of soil characteristics. The regionalised soil characteristics are unclassified and will be classified to solve particular problems (as erosivity-classes). Using the data being available for large areas (see: left column of the following table or "basic data") about soil relevant geo factors and selective soil survey (soil profiles) is the base for making (creating) functional soil maps being mainly digital. The following table shows the most important differences between common soil maps and functional soil maps:
Some differences between common soil maps and functional soil maps
| Common soil maps (analogue and digital) | Functional soil mapping (done by SAGA) | |
| data origin |
Available soil relevant data (like: soil evaluation, geological maps, terrain maps, historical maps) Soil survey (soil profiles) |
Available data for huge areas: Digital Terrain Models, climatic models, land-use and vegetation data Available selective data: Climatic tables, hydrological data Available soil profiles or soil survey |
| Preparing the mapping |
evaluating the available soil relevant data (see above) Partly with computing: producing soil relevant data sets as "layer" |
- |
| Producing the soil maps |
Converting the available data (partly using computerised support) Partly GIS oriented cutting of the soil relevant layers (see above) for homogenous "smallest areas" Predicting soil contribution (conceptional maps) with the help of expert systems based on homogenous "smallest areas" Producing the soil maps: Deductive mainly subjective evaluation of the available data and soil surveys as well as showing the mapping units of a map
|
Producing soil relevant area-data sets by converting the data referring the large areas or points: geo factor terrain (catchment area and -inclinations), climate (precipitation, temperature), etc. and processes (water balance and transport) with the help of deterministic, physical and geo statistical methods Inductive investigation of the coherence between (punctual) soil characteristics and soil relevant area-data sets Regionalisation of different soil characteristics Maybe: manual correction |
| Form of data storage | Classified, based on mapping units (vector data), analogue and digital | Unclassified, based on grid cells (grid data), digital |
| Substance of the soil map |
Genetic oriented soil map (soil types or soil series) based on mapped areas Maybe: evaluation maps based on mapped areas |
Unclassified grid data sets of different soil characteristics and regionalised soil relevant geo factors and processes Usable (classified) evaluation maps (i. e. erosivity, ground water recharge) |
There are several functional soil maps within the products "Soil": "Soil Textures", "Soil Water" and "Soil Erosion". Please choose within the navigation (left frame).