Зольников И.Д.   Лямина В.А.   Chupina D.A.   Selyatickay N.A.  

GIS mapping of a geomorphical basis of the Chu steppe landscapes.

Reporter: Chupina D.A.

The current stage of a geomorphological research is characterized by active using of GIS technologies for mapping forms and types of terrain. However, the degree of GIS methods introduction in the geomorphological mapping are differ among various scientific and educational organizations and there are no standard methodologies for replication them to solve production problems (in particular for geological and landscape mapping). So, development of complex technologies of geoinformation mapping of relief types on a basis of morphometric parameters seems to be relevant and meaningful, at least in the applied aspect. We have developed such technology on the example of the Chu basin (Gorny Altai) relief complexes.
The foundation of the work was digital elevation model SRTM. On its basis the series of morphometric parameters was built, each of them was evaluated in terms of efficiency for the detection of morphogenetic complex terrain. It turned out that many traditional settings, effective for neotectonic constructions (altitude, exposure and slope, basin hudrologic models, etc.) are not suitable for direct comparison of erosion and accumulation types of Quaternary terrain that are distributed on a bottom intermountain basin. We used ratios averaged by the “sliding window” method on some neighborhood (vertical and horizontal dissection of a relief, slopes range, azimuth range). To calculate relative azimuth characteristics a two measures of deviation from  eastward (sublatitudinal projection) and northward (sublongitudinal projection) have been constructed. These relative density parameters allowed to detect  similarity of relief the same origin for earth's surface located at different altitudes neotectonic blocks with different exposures. To reduce the influence of mountain  contrasting relief, composed of Paleozoic bedrock, a mask was used.
These selected morphometric parameters were processed by methods of controlled classifications typically used for object recognition in multispectral satellite images. For this purpose a ground-based observations at the reference sites geodatabase was used. As a result, we have managed to allocate these Chu steppes relief types: glacial trough-ridge, limnetic at the aleurite-sand base, limnetic at the moraine base, limnetic with a bars, talus-proluvial, thermokarst, alluvial of the Chu river valley, alluvial of tributaries, solifluction. Application of relative density morphometric indices, calculated for a particular area by the “sliding window” method, allowed us to move from mapping landforms and their elements to mapping of relief types that are the natural combination of typical geomorphological sites. These studies have shown expediency complexing of the methods of raster processing and of grid modeling for the Quaternary morphogenetic types of relief mapping. In our opinion, proven technology is promising for the medium-scale geomorphological map construction at the landscape and geological mapping.


Abstracts file: И.Д. Зольников, В.А. Лямина, Д.А. Чупина, Н.А. Селятицкая..rtf

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