Module Terrain Map View
This module allows one to create different terrain visualisations from an elevation dataset:
* Topography: a simple map with an analytical hillshading of the terrain
* Morphology: a map which visualizes the terrain by combining positive and negative openess (Yokoyama et al. 2002) with terrain slope in a single map. In contrast to conventional shading methods this has the advantage of being independent from the direction of the light source.
References:
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: Copyrights (c) 2014 by Volker Wichmann
- Specification: grid
- Menu: Visualization|Grid
Parameters
| | Name | Type | Identifier | Description | Constraints |
|---|
| Input | DEM | Grid (input) | DEM | Digital elevation model. | - |
| Output | Shade (*) | Grid (optional output) | SHADE | The shaded DTM. | - |
| Openness (*) | Grid (optional output) | OPENNESS | The difference of positive and negative openness. | - |
| Slope (*) | Grid (optional output) | SLOPE | The calculated terrain slope [radians]. | - |
| Contours (*) | Shapes (optional output) | CONTOURS | The generated contour lines. | - |
| Options | Method | Choice | METHOD | Choose the map type to generate. | Available Choices:
[0] Topography
[1] Morphology
Default: 0 |
| Radial Limit | Floating point | RADIUS | Radial search limit for openness calculation. | Minimum: 0.000000
Default: 1000.000000 |
| Contour Lines | Boolean | CONTOUR_LINES | Derive contour lines. | Default: 1 |
| Equidistance | Floating point | EQUIDISTANCE | Contour lines equidistance [map units]. | Minimum: 0.000000
Default: 50.000000 |
| (*) optional |
Command-line
Usage: saga_cmd grid_visualisation 8 -DEM <str> [-SHADE <str>] [-OPENNESS <str>] [-SLOPE <str>] [-CONTOURS <str>] [-METHOD <str>] [-RADIUS <str>] [-CONTOUR_LINES <str>] [-EQUIDISTANCE <str>]
-DEM:<str> DEM
Grid (input)
-SHADE:<str> Shade
Grid (optional output)
-OPENNESS:<str> Openness
Grid (optional output)
-SLOPE:<str> Slope
Grid (optional output)
-CONTOURS:<str> Contours
Shapes (optional output)
-METHOD:<str> Method
Choice
Available Choices:
[0] Topography
[1] Morphology
Default: 0
-RADIUS:<str> Radial Limit
Floating point
Minimum: 0.000000
Default: 1000.000000
-CONTOUR_LINES:<str> Contour Lines
Boolean
Default: 1
-EQUIDISTANCE:<str> Equidistance
Floating point
Minimum: 0.000000
Default: 50.000000