Aesthetic 3D-Index
By means of a volumetric GIS we can even quantitatively characterise
the structure of landscape units regarding the 3rd dimension.
The quotient of the planimetric surface area and the real surface area
is a measure to describe the roughness of a landscape. It is vital to use
DEM data, that considers all landscape elements with a z-value (like the
modified surface models above). The 3D index represents the structure of
a landscape corresponding to the graphical illustration of it.
We finally state that areas, which are well structured
have a lower index (< 0,95) than poorly structured landscapes (0.95
and higher). The 3D index changes with the increment of forests and buildings.
Many isolated forests with a high edge effect depress the index, extended
compact forest areas increase the index.
.
PF = Planimetric Area
GF = Surface Area
GV = Relief Volume
3D-Index = PF/GF
.
Abb. 5.33: Relief im Norden des Untersuchungsgebietes.
PF = 2031 ha, GF = 2117 ha, GV = 1,96 km3,
3D-index = 0,96
Abb. 5.34: Relief im Süden des Untersuchungsgebiet.
PF = 2348 ha, GF = 2533 ha, GV = 1,61 km3,
3D-Index = 0,93
Abb. 5.35: Relief von strukturarmen Flächen.
PF = 664 ha, GF = 675 ha, GV = 0,24 km3,
3D-Index = 0,98
Abb. 5.36: Relief von strukturreichen Flächen.
PF = 1748 ha, GF = 1950 ha, GV = 1,60 km3,
3D-Index = 0,90