Geomorphometry Terms

Geomorphometric Parameters  

Parameter Formula Interpretation of Values Reference
Flatness Ln(S1/S2) Large values indicate flat terrain, low values rugged terrain.  Correlates strongly and negatively with slope or relief. Guth papers listed in Terrain organization
Organization Ln(S2/S3) Large values indicate a dominant linear fabric to the terrain, low values isotropic topography Guth papers listed in Terrain organization
Orientation Trend of S3 Dominant trend to the terrain fabric, direction between 0 and 180. Used in eigenvector analysis of SSO diagrams. Guth papers listed in Terrain organization
Strength, c Ln(S1/S3) Large values indicate flat terrain, low values rugged terrain.  Very similar to the flatness parameter.  Correlates strongly and negatively with slope or relief. Used in eigenvector analysis of SSO diagrams. Fisher, Lewis, and Embleton, p.159
Shape, k Ln(S1/S2)/Ln(S2/S3) Large values indicate a dominant linear fabric to the terrain, low values isotropic topography.  Correlates moderately with organization. Fisher, Lewis, and Embleton, p.159
Ghost ratio (Percentage points on contour lines) / (Percentage elevations that are contour lines) Indicates the overrepresentation of contour line elevations in the DEM, an artifact of the digitizing process if the ghost ratio exceeds 1.  The ghost ratio is never significantly less than 1. Guth, 1999

S1, S2, and S3 are the eigenvalues from the 3x3 matrix of the sums of the cross products of the direction cosines for all points in the analysis region.

S1> S2> S3.

 


Last modified 5/24/2006