Improving a digital elevation model of Antarctica using radar remote sensing data and GIS techniques1

1999 ◽  
Vol 23 (3) ◽  
pp. 185-200 ◽  
Author(s):  
Kenneth C. Jezek ◽  
Hongxing Liu ◽  
Zhiyuan Zhao ◽  
Biyan Li
2021 ◽  
Vol 70 (1) ◽  
pp. 29-38
Author(s):  
Robert Schiestl

Abstract. The Butic Canal – a Roman period transversal route across the northern Nile Delta – was the longest artificial watercourse in the Nile Delta, yet it remains very poorly understood. To date, the canal has not yet been verified by archeological excavations. The route of the eastern section of the canal has been indirectly identified based on a linear elevated feature most likely representing earth from the excavation of the canal. This study combines the analysis of historical sources and remote sensing data, such as satellite imagery and the TanDEM-X digital elevation model, in order to discuss its date of construction, route, and functions. Based on the data of the digital elevation model, new constructional features are visible in the eastern delta providing the first detailed route of a Roman-era artificial watercourse in Egypt. It is suggested that the canal's construction is placed in the context of imperial investments in the infrastructure of the eastern part of the Roman empire.


2007 ◽  
Vol 79 (4) ◽  
pp. 693-711 ◽  
Author(s):  
Clauzionor L. Silva ◽  
Norberto Morales ◽  
Alvaro P. Crósta ◽  
Solange S. Costa ◽  
Jairo R. Jiménez-Rueda

An investigation of the tectonic controls of the fluvial morphology and sedimentary processes of an area located southwest of Manaus in the Amazon Basin was conducted using orbital remote sensing data. In this region, low topographic gradients represent a major obstacle for morphotectonic analysis using conventional methods. The use of remote sensing data can contribute significantly to overcome this limitation. In this instance, remote sensing data comprised digital elevation model (DEM) acquired by the Shuttle Radar Topographic Mission (SRTM) and Landsat Thematic Mapper images. Advanced image processing techniques were employed for enhancing the topographic textures and providing a three-dimensional visualization, hence allowing interpretation of the morphotectonic elements. This led to the recognition of main tectonic compartments and several morphostructural features and landforms related to the neotectonic evolution of this portion of the Amazon Basin. Features such as fault scarps, anomalous drainage patterns, aligned ridges, spurs and valleys, are expressed in the enhanced images as conspicuous lineaments along NE-SW, NW-SE, E-W and N-S directions. These features are associated to the geometry of alternated horst and graben structures, the latter filled by recent sedimentary units. Morphotectonic interpretation using this approach has proven to be efficient and permitted to recognize new tectonic features that were named Asymmetric Ariaú Graben, Rombohedral Manacapuru Basin and Castanho-Mamori Graben.


Author(s):  
Valerii Kulygin ◽  
Samir Misirov

The study of the ridge systems’ morphology on accumulative coastal land forms makes it possible to reconstruct their development. The spatial orientation and height of the beach ridges provide information on the predominance of certain processes at different time intervals. The Dolgaya Spit, which is one of the largest accumulative forms of the Sea of Azov, is characterized by the presence of well-distinguishable generation of sand-shell ridges. The article discusses the possibility of using various remote sensing data to identify beach ridges on the Dolgaya Spit. In this study the data of ground measurements of elevation points performed during the expedition in the summer of 2020 are used. The statistical characteristics of the ridges on the investigated area of the spit are given. The analysis of the possibility of identifying beach ridges on the spit based on high-resolution satellite optical images has been done. It was concluded that it is impossible to unambiguously determine the ridges, since the optical characteristics of the soil and vegetation cover on the Dolgaya Spit do not allow separation of the microrelief forms. The second source of remote sensing data was aerial photography of a part of the Dolgaya Spit using the unmanned aerial vehicle “Phantom 3 PRO”, followed by photogrammetric processing of the obtained digital images. The stages of processing the survey results for the construction of a digital elevation model and an orthomosaic of the investigated area are considered. The quality of the obtained digital elevation model was assessed by comparison with ground measurements of elevation points. The article discusses the source of errors in the obtained digital elevation model. It is noted that the construction of a digital elevation model with acceptable quality is possible only for the spit’s regions with sparse vegetation cover.


Water ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1585
Author(s):  
Hong Cao ◽  
Zhao Pan ◽  
Qixin Chang ◽  
Aiguo Zhou ◽  
Xu Wang ◽  
...  

The hydrological information derived from a digital elevation model is very important in distributed hydrological modeling. As part of alpine hydrological research on stream network modeling using remote sensing data in the northeast of the Tibetan Plateau, three digital elevation model (DEM) datasets were obtained for the purpose of hydrological features, mainly including channel network, watershed extent and terrain character. The data sources include the airborne light detection and ranging (LiDAR) with point spacing of 1 m, the High Mountain Asia (HMA) DEM and the Shuttle Radar Topography Mission (SRTM) DEM. Mapping of the watershed and stream network was conducted using each of the three DEM datasets. The modeled stream networks using the different DEMs were verified against the actual network mapped in the field. The results show that the stream network derived from the LiDAR DEM was the most accurate representation of the network mapped in the field. The SRTM DEM overestimated the basin hypsometry relative to the LiDAR watershed at the lowest elevation, while the HMA DEM underestimated the basin hypsometry relative to the LiDAR watershed at the highest elevation. This may be because, compared with the SRTM DEM and the HMA DEM, the LiDAR DEM has higher initial point density, accuracy and resolution. It can be seen that the LiDAR data have great potential for the application in hydrologic modeling and water resource management in small alpine catchments.


Author(s):  
Andrew N. Beshentsev ◽  
◽  
Alexander A. Ayurzhanaev ◽  
Bator V. Sodnomov ◽  
◽  
...  

The article is aimed at the development of methodological foundations for the creation of geoin-formation resources of transboundary territories based on cartographic materials and remote sensing data, as well as physical and geographical zoning of the transboundary Russian-Mongolian territory. The methodological basis of the study is cartographic and statistical research methods, geoinformation technology, as well as processing and analysis of remote sensing data. As a result, the study deter-mines the features of geoinformation resources, presents their characteristics, develops a classification and substantiates their integrating value in making interstate territorial decisions. The article gives the physical and geographical characteristics of the territory, determines the scale of mapping, establishes the basic units of geoinformation mapping and modeling, creates the coverage of the basin division, and proposes a scheme for creating basic geoinformation resources for the physical and geographical zoning of the territory. Based on the analysis of the digital elevation model, the territory was zoned according to the morphometric parameters of the relief. As a result of processing and analysis of Landsat images at different times, the territory was zoned in terms of the amount of photosynthetically active biomass (NDVI). As a result of zoning, 6 physical-geographical regions and 33 physical-geographical areas were identified.


Geosciences ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 248 ◽  
Author(s):  
Mariaelena Cama ◽  
Calogero Schillaci ◽  
Jan Kropáček ◽  
Volker Hochschild ◽  
Alberto Bosino ◽  
...  

Soil erosion represents one of the most important global issues with serious effects on agriculture and water quality, especially in developing countries, such as Ethiopia, where rapid population growth and climatic changes affect widely mountainous areas. The Meskay catchment is a head catchment of the Jemma Basin draining into the Blue Nile (Central Ethiopia) and is characterized by high relief energy. Thus, it is exposed to high degradation dynamics, especially in the lower parts of the catchment. In this study, we aim at the geomorphological assessment of soil erosion susceptibilities. First, a geomorphological map was generated based on remote sensing observations. In particular, we mapped three categories of landforms related to (i) sheet erosion, (ii) gully erosion, and (iii) badlands using a high-resolution digital elevation model (DEM). The map was validated by a detailed field survey. Subsequently, we used the three categories as dependent variables in a probabilistic modelling approach to derive the spatial distribution of the specific process susceptibilities. In this study we applied the maximum entropy model (MaxEnt). The independent variables were derived from a set of spatial attributes describing the lithology, terrain, and land cover based on remote sensing data and DEMs. As a result, we produced three separate susceptibility maps for sheet and gully erosion as well as badlands. The resulting susceptibility maps showed good to excellent prediction performance. Moreover, to explore the mutual overlap of the three susceptibility maps, we generated a combined map as a color composite where each color represents one component of water erosion. The latter map yields useful information for land-use managers and planning purposes.


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