Topographic Signatures in Geology
| T.G. Farr, D.L. Evans
||Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA USA
Topographic information is required for many Earth Science investigations.
For example, topography is an important element in regional and
global geomorphic studies because it reflects the interplay between
the climate-driven processes of erosion and the tectonic processes
of uplift. A number of techniques have been developed to analyze
digital topographic data, including Fourier texture analysis.
A Fourier transform of the topography of an area allows the spatial
frequency content of the topography to be analyzed. Band-pass
filtering of the transform produces images representing the amplitude
of different spatial wavelengths. These are then used in a multi-band
classification to map units based on their spatial frequency content.
Results using a radar image instead of digital topography showed
good correspondence to a geologic map, however brightness variations
in the image unrelated to topography caused errors. An additional
benefit to the use of Fourier band-pass images for the classification
is that the textural signatures of the units are quantitative
measures of the spatial characteristics of the units that may
be used to map similar units in similar environments. * Work performed
under contract to NASA.
Keywords: Topography, Geology, Texture, Fourier analysis
Keywords: ESA European
Space Agency - Agence spatiale europeenne,
observation de la terre, earth observation,
satellite remote sensing,
teledetection, geophysique, altimetrie, radar,
chimique atmospherique, geophysics, altimetry, radar,