Datenpaket: Geomorphological Landform Classification of Bavaria

Geomorphon-based classification of landforms across Bavaria at 5 m spatial resolution, derived from the Bavarian Digital Terrain Model (DGM5). The classification characterizes local relief geometry using a search distance of 250 m and an angular threshold of 1°. No additional hydrological conditioning of the DGM5 was applied prior to geomorphon classification. Consequently, terrain structures represented in the DGM5, including anthropogenic features, may be reflected in the resulting landform classes.

This dataset provides a Bavaria-wide classification of landforms based on the geomorphon approach developed by Jasiewicz & Stepinski (2013). Geomorphons are geomorphological phenotypes that characterize local terrain forms based on the relative elevation relationships between a raster cell and its surrounding terrain.
The classification was derived from the Digital Terrain Model of Bavaria (DGM5) with a spatial resolution of 5 m. Landforms are identified by evaluating the local relief geometry around each raster cell and are assigned to ten geomorphon classes: flat, summit, ridge, shoulder, spur, slope, hollow, footslope, valley, and depression.
The geomorphon analysis was performed using a search distance of 250 m, corresponding to 50 raster cells at 5 m spatial resolution, an angular threshold of 1°, and line tracing in eight directions. The angular threshold controls the sensitivity of the classification to differences in local terrain geometry.
The DGM5 used as input is a preprocessed digital terrain model. No additional hydrological conditioning was applied prior to the geomorphon classification. In particular, the terrain was not modified specifically to enforce hydrological connectivity or drainage patterns for the purpose of this analysis.
Consequently, the resulting geomorphon classes describe the terrain geometry represented by the DGM5 rather than a hydrologically conditioned terrain surface. Terrain structures represented in the DGM5, including anthropogenic features such as embankments, dams, cuttings, or other artificial modifications of the terrain, may therefore be reflected in the resulting landform classification.
The dataset provides a spatially comprehensive characterization of topographic heterogeneity across Bavaria. The mapped classes represent a relief-geometric classification of the terrain surface represented in the DGM5. They should not be interpreted as direct evidence of landform genesis, hydrological connectivity, or currently active geomorphological processes.

INPUT DATA
Digital Terrain Model of Bavaria (DGM5)
• Spatial resolution: 5 m
• Data provider: Bavarian Surveying Administration / Bayerische Vermessungsverwaltung
• Product: Digitales Geländemodell 5 m (DGM5)
• License: CC BY 4.0
• Source: Open Data Bayern

DATASET SPECIFICATIONS
• Spatial extent: Bavaria, Germany
• Spatial resolution: 5 m
• Unit: categorical classes; dimensionless
• Number of classes: 10
• Data type: raster
• File format: GeoTIFF / Cloud Optimized GeoTIFF (COG)
• Coordinate reference system: ETRS89 / UTM zone 32N
• EPSG: 25832

PROCESSING
Input: Digital Terrain Model of Bavaria (DGM5), 5 m spatial resolution.
Method: Geomorphon classification according to Jasiewicz & Stepinski (2013).

Geomorphons classify terrain based on patterns of relative elevation within a defined surrounding area. The method compares the central raster cell with its surrounding terrain along multiple search directions and derives characteristic terrain forms from the resulting pattern.

The DGM5 used as input is a preprocessed digital terrain model. No additional hydrological conditioning of the terrain was applied prior to geomorphon classification.
The geomorphon classification therefore represents the relief geometry contained in the DGM5 rather than a hydrologically conditioned representation of the terrain. Anthropogenic terrain structures represented in the DGM5 may consequently influence the assigned geomorphon classes.
The search distance defines the spatial neighborhood considered for identifying terrain forms. With a radial limit of 50 cells and a raster resolution of 5 m, terrain geometry is evaluated over a search distance of 250 m. The threshold angle of 1° determines the sensitivity of the classification to differences in relative terrain geometry.

CLASSIFICATION
The raster contains ten geomorphon classes English / German: 1 – Flat / Ebene (Flachland), 2 – Summit (Peak) / Gipfel, 3 – Ridge / Rücken (Grat), 4- Shoulder / Hangschulter (Hangoberkante), 5 – Spur (convex slope) / Hang (Sporn), 6 – Slope / Hang, 7 – Hollow (concave slope) / Hohlform (Mulde), 8 – Footslope / Hangfuß, 9 – Valley / Tal, 10 – Depression (pit) / Senke (Grube)

INTERPRETATION AND LIMITATIONS
The dataset represents a geometric classification of terrain morphology and should be interpreted accordingly.
In particular:
• The classification is derived from the terrain geometry represented in the DGM5.
• The input DGM5 is a preprocessed digital terrain model.
• No additional hydrological conditioning was performed specifically.
• The dataset therefore does not represent a hydrologically conditioned terrain model.
• Anthropogenic terrain structures represented in the DGM5, including embankments, dams, cuttings, and similar features, may be expressed in the geomorphon classification.
• Classes such as valley, hollow, or depression describe terrain-geometric forms and do not necessarily represent hydrologically connected drainage structures.
• Likewise, the geomorphon classes do not provide information about the genesis of individual landforms.
• The classes should not be interpreted as direct indicators of currently active geomorphological or hydrological processes.
• The spatial characteristics of the classification depend on the selected geomorphon parameters, particularly the 250 m search distance and the 1° angular threshold.
The dataset is therefore intended primarily for the characterization and spatial differentiation of terrain morphology and topographic heterogeneity.

RECOMMENDED USE
The dataset can be used as a terrain-related spatial variable in regional and Bavaria-wide analyses, including environmental modelling, landscape characterization, ecological analyses, agricultural applications, biodiversity studies, and other analyses requiring information on local terrain morphology.
For applications requiring explicit representation of surface runoff, drainage networks, flow accumulation, or hydrological connectivity, hydrologically conditioned elevation data and dedicated hydrological terrain derivatives should be used instead.

REFERENCES
Jasiewicz, J., & Stepinski, T. F. (2013). Geomorphons — A pattern recognition approach to classification and mapping of landforms. Geomorphology, 182, 147–156. DOI: 10.1016/j.geomorph.2012.11.005.
Bogaart, P. W., & Troch, P. A. (2006). Curvature distribution within hillslopes and catchments and its effect on the hydrological response. Hydrology and Earth System Sciences, 10, 925–936.

DATA SOURCE
Digitales Geländemodell 5 m (DGM5), Bavarian Surveying Administration / Bayerische Vermessungsverwaltung, Open Data Bayern, licensed under CC BY 4.0.