Landform and Topography

Historically, terrain information has been represented and visualized as couture lines, i.e. lines connecting points with identical elevation values. This was primary because of the way this information was collected, first through field mapping and later through stereoscopic Stereoscopic photogrammetry. While couture lines are still used for terrain visualisation on many maps, they are unsuitable for digital representation aimed at 3d visualisation and modelling. For these purposes, a Raster Data-based representation or a 2.5D Triangulation model [TIN model]

Representation of Buildings and Tunnels

There are several problems in relation to the representation of bridges and tunnels namely:

• How do bridges influence the terrain model, and how does this affect hydrological modelling

Topography related to the shape and elevation of the Earth’s land surface and ocean/lake floors (e.g., Digital surface Models (DSM’s), Digital Terrain Models (DTM’s), bathymetry charts, derived slope, aspect, and curvature maps, geomorphological features).

Derived surface properties

Properties computed from the terrain surface, or describing the surface as a boundary for water and air, also belong here. They were previously the Toposphere twigs Surface Physical and Surface Radiative and Thermal.

• Terrain derivatives: Slope, aspect, curvature, flow direction, and flow accumulation
• Solar exposure: Insolation, hillshade, and sky-view factor computed from the DSM/DTM
• Surface roughness: Aerodynamic roughness length (z₀) for wind modelling, and hydraulic roughness for overland flow
• Albedo and emissivity: Surface reflectivity and thermal emission characteristics

Related properties sit elsewhere in the network:

• Land surface temperature links to atmosphere_climate.
• Sea surface temperature belongs to hydrosphere_marine.
• Infiltration capacity belongs to geosphere_soil_properties.
• Impervious surface is land cover, so it belongs to anthroposphere_perception_thematics.

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