Module Topographic Openness
Topographic openness expresses the dominance (positive) or enclosure (negative) of a landscape location. See Yokoyama et al. (2002) for a precise definition. Openness has been related to how wide a landscape can be viewed from any position. It has been proven to be a meaningful input for computer aided geomorphological mapping.
References:
Anders, N. S. / Seijmonsbergen, A. C. / Bouten, W. (2009): Multi-Scale and Object-Oriented Image Analysis of High-Res LiDAR Data for Geomorphological Mapping in Alpine Mountains. Proceedings of Geomorphometry 2009. online at geomorphometry.org.
Prima, O.D.A / Echigo, A. / Yokoyama, R. / Yoshida, T. (2006): Supervised landform classification of Northeast Honshu from DEM-derived thematic maps. Geomorphology, vol.78, pp.373-386.
Yokoyama, R. / Shirasawa, M. / Pike, R.J. (2002): Visualizing topography by openness: A new application of image processing to digital elevation models. Photogrammetric Engineering and Remote Sensing, Vol.68, pp.251-266. online at ASPRS.
- Author: O.Conrad (c) 2012
- Specification: grid
- Menu: Terrain Analysis|Lighting
Parameters
| | Name | Type | Identifier | Description | Constraints |
|---|
| Input | Elevation | Grid (input) | DEM | - | - |
| Output | Positive Openness | Grid (output) | POS | - | - |
| Negative Openness | Grid (output) | NEG | - | - |
| Options | Radial Limit | Floating point | RADIUS | - | Minimum: 0.000000
Default: 10000.000000 |
| Method | Choice | METHOD | - | Available Choices:
[0] multi scale
[1] sectors
Default: 1 |
| Multi Scale Factor | Floating point | DLEVEL | - | Minimum: 1.250000
Default: 3.000000 |
| Number of Sectors | Integer | NDIRS | - | Minimum: 2
Default: 8 |
Command-line
Usage: saga_cmd ta_lighting 5 [-DEM <str>] [-POS <str>] [-NEG <str>] [-RADIUS <str>] [-METHOD <str>] [-DLEVEL <str>] [-NDIRS <num>]
-DEM:<str> Elevation
Grid (input)
-POS:<str> Positive Openness
Grid (output)
-NEG:<str> Negative Openness
Grid (output)
-RADIUS:<str> Radial Limit
Floating point
Minimum: 0.000000
Default: 10000.000000
-METHOD:<str> Method
Choice
Available Choices:
[0] multi scale
[1] sectors
Default: 1
-DLEVEL:<str> Multi Scale Factor
Floating point
Minimum: 1.250000
Default: 3.000000
-NDIRS:<num> Number of Sectors
Integer
Minimum: 2
Default: 8