• 5 meter interval sampling of contours
• 5 meter interval sampling of terrain skeleton
• [5 10 15 20 25 30 40 50 60] meter thinning (snapping) radius

 
Compute SD of elevation on 50x50 meter grid

 
Site Description:

• Description on the US Forest Service site

Fig. 1

Fig. 2

Fig. 3

Fig. 4

Fig. 5

Initial classification of terrain based on 9 topographic parameters extracted from a 10 meter DEM. Slope, profile curvature, maximum curvature, minimum curvature, longitudinal curvature, and cross-sectional curvature were computed from a 15x15 moving window by r.param.scale. A 9x9 moving window was used to compute the hypsometric integral as defined by Wood and Snell (1960). These 7 parameters were extracted from a given region, and classified with the clara() function from the cluster package in R. Transferal of raster data between GRASS and R was made possible by the spgrass6 package. An excellent overview of some of the features in the spgrass6 package is included in the third volume of the GRASS newsletter. Some initial results are displayed in Figures 1 and 2. Terrain data is better visualized in 3 dimensions: Figure 3 contains a view of both Temblor and Volcanic lanforms near McCabe Canyon. Ideas for this type of classification technique came from Roger Bivand (Bivand, 2000).

http://www.uscgislab.net/incEngine/index.php?art=software

http://www.uscgislab.net/incEngine/index.php?art=theses

Example LiDAR dataset

Stream Network Detail

Raw LiDAR data is so detailed that localized flow routing algorithms often fail to produce meaningful results. The terraflow algorithm is one such method that appears to work well on such massive grid objects (Homepage).

GRASS Vectors

SSURGO cutaway

Slope class cutaway

Topomap

Panchromatic

Near infrared

Geomorphic features.

View of Mt. Defiance from Bear Valley, Pinnacles National Monument. Pan Chromatic 2m res.

Thanks to Markus Neteler for initial insight on how to build an appropriate POVRAY script file.

• Read more