Study on Geomorphologic Spatial Information Mining and Application

2011 ◽  
Vol 250-253 ◽  
pp. 1236-1242
Author(s):  
Li Heng Liang ◽  
Li Xin Xing ◽  
Tong Lin Li ◽  
Hong Yan Jiang ◽  
Li Jun Jiang
Keyword(s):  
Land Surface ◽  
Spatial Information ◽  
Digital Elevation Models ◽  
Three Dimensional ◽  
Shuttle Radar Topography Mission ◽  
Digital Elevation ◽  
Elevation Data ◽  
Local Relief ◽  
Local Window ◽  
Three Dimensional Coordinate

Digital Elevation Models (DEM) implies numbers of geomorphologic spatial information. It not only includes the three-dimensional coordinate but also has unique texture information, which can describe the ‘true’ land surface adequately at relation of neighbors (plan) and relative (amplitude). We will use a method to study the wavelength characters by data mining and distribution of slope and local relief on the altitude steps through a local window. The Shuttle Radar Topography Mission (SRTM) collect detailed Digital Elevation Models(DEM) data between 60°N and 57°S, 80 percent for all land masses, and it provides reliable, high precision surface elevation data for us, suits to analyze efficiently landscape pattern. SRTM-DEM data simulate three-dimensional land surface with regular gridded matrix, and these discrete points are fit for spatial neighbors’ analysis and statistics, and convenient to geomorphologic pattern computation and analysis in digital computer. Geomorphologic pattern is influenced by Physical properties and human activities in a most direct way, but whilst it record numbers of geological evolution evidence, and these records provide some important information for climate change, geological and geographical processes and ecological environment researches in science. In this study, making the whole Jilin province as study object, we propose a fourth-order equation to approximate land as a continuous curved surface, association neighbors’ analysis method, utilize digital elevation matrix to validate an optimal statistic window, and subsequent study the area spatial distribution by parameterization and classification, get a satisfactory effect.

scholarly journals COMPARING ICESAT/GLAS BASED ELEVATION HEIGHTS WITH PHOTOGRAMMETRIC TERRAIN HEIGHTS FROM UAV-IMAGERY ON THE EAST TIBETAN PLATEAU

2015 ◽  
Vol XL-3/W3 ◽  
pp. 385-390 ◽  
Author(s):  
F. Enßle ◽  
A. Fritz ◽  
B. Koch
Keyword(s):  
Tibetan Plateau ◽  
Digital Elevation Models ◽  
Shuttle Radar Topography Mission ◽  
Aerial Images ◽  
Laser Altimeter ◽  
Ice Cloud ◽  
Digital Elevation ◽  
Surface Models ◽  
Elevation Data ◽  
Data Source

Digital elevation models (DEMs) and height measurements are broadly used in environmental studies. Two common elevation sources are the Ice Cloud and land elevation Satellite (ICESat), which acquired laser range measurements with the Geoscience Laser Altimeter System (GLAS) across the globe and elevation data from the Shuttle Radar Topography Mission (SRTM). Current developments of small unmanned aerial vehicles (UAV) provide the opportunity to collect aerial images of remote areas at a high spatial resolution. These can be further processed to digital surface models by stereophotogrammetry and provide a reliable data source to evaluate coarse scale Digital Elevation Models (DEMs). <br><br> This study compares ICESat/GLAS and SRTM90 elevation data against photogrammetric terrain heights within GLAS footprints on high altitudes on the East Tibetan Plateau. Without vegetation-bias, we were able to examine height differences under different topographic conditions and of different acquisition dates. Several resampling techniques were applied to SRTM90 data and averaged height within each footprint was calculated. ICESat/GLAS heights (n = 148) are most similar to UAV data based elevations with an averaged difference of &minus;0.8m ±3.1m. Results furthermore indicate the validity of ICESat/GLAS heights, which are usually removed from analyses by applying different quality flags. Smallest difference of SRTM90 to UAV based heights could be observed by a natural neighbour resampling technique (averaged 3.6m ±14m), whereat other techniques achieved quite similar results. It can be confirmed that within a range of 3,800&ndash;4,200m above mean sea level the ICESat/GLAS heights are a precise source to determine elevation at footprint geolocation.

scholarly journals A Relief Dependent Evaluation of Digital Elevation Models on Different Scales for Northern Chile

2019 ◽  
Vol 8 (10) ◽  
pp. 430 ◽  
Author(s):  
Kramm ◽  
Hoffmeister
Keyword(s):  
High Resolution ◽  
Laser Scanning ◽  
Thermal Emission ◽  
Comprehensive Evaluation ◽  
Digital Elevation Models ◽  
Shuttle Radar Topography Mission ◽  
Northern Chile ◽  
Digital Elevation ◽  
Elevation Data ◽  
Position Index

Many geoscientific computations are directly influenced by the resolution and accuracy of digital elevation models (DEMs). Therefore, knowledge about the accuracy of DEMs is essential to avoid misleading results. In this study, a comprehensive evaluation of the vertical accuracy of globally available DEMs from Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER), Shuttle Radar Topography Mission (SRTM), Advanced Land Observing Satellite (ALOS) World 3D and TanDEM-X WorldDEM™ was conducted for a large region in Northern Chile. Additionally, several very high-resolution DEM datasets were derived from Satellite Pour l’Observation de la Terre (SPOT) 6/7 and Pléiades stereo satellite imagery for smaller areas. All datasets were evaluated with three reference datasets, namely elevation points from both Ice, Cloud, and land Elevation (ICESat) satellites, as well as very accurate high-resolution elevation data derived by unmanned aerial vehicle (UAV)-based photogrammetry and terrestrial laser scanning (TLS). The accuracy was also evaluated with regard to the existing relief by relating the accuracy results to slope, terrain ruggedness index (TRI) and topographic position index (TPI). For all datasets with global availability, the highest overall accuracies are reached by TanDEM-X WorldDEM™ and the lowest by ASTER Global DEM (GDEM). On the local scale, Pléiades DEMs showed a slightly higher accuracy as SPOT imagery. Generally, accuracy highly depends on topography and the error is rising up to four times for high resolution DEMs and up to eight times for low-resolution DEMs in steeply sloped terrain compared to flat landscapes.

scholarly journals An algorithm for delineating and extracting hillslopes and hillslope width functions from gridded elevation data

2011 ◽  
Vol 8 (5) ◽  
pp. 8865-8901
Author(s):  
P. Noel ◽  
A. N. Rousseau ◽  
C. Paniconi
Keyword(s):  
Three Dimensional ◽  
Rainfall Runoff ◽  
Dimensional Representation ◽  
New Approach ◽  
One Dimensional ◽  
Digital Elevation ◽  
Elevation Data ◽  
Average Profile ◽  
Elevation Model ◽  
Digital Elevation Model Resolution

Abstract. Subdivision of catchment into appropriate hydrological units is essential to represent rainfall-runoff processes in hydrological modelling. The commonest units used for this purpose are hillslopes (e.g. Fan and Bras, 1998; Troch et al., 2003). Hillslope width functions can therefore be utilised as one-dimensional representation of three-dimensional landscapes by introducing profile curvatures and plan shapes. An algorithm was developed to delineate and extract hillslopes and hillslope width functions by introducing a new approach to calculate an average profile curvature and plan shape. This allows the algorithm to be independent of digital elevation model resolution and to associate hillslopes to nine elementary landscapes according to Dikau (1989). This algortihm was tested on two flat and steep catchments of the province of Quebec, Canada. Results showed great area coverage for hillslope width function over individual hillslopes and entire watershed.

scholarly journals Bag of Geomorphological Words: A Framework for Integrating Terrain Features and Semantics to Support Landform Object Recognition from High-Resolution Digital Elevation Models

2020 ◽  
Vol 9 (11) ◽  
pp. 620
Author(s):  
Xiran Zhou ◽  
Xiao Xie ◽  
Yong Xue ◽  
Bing Xue ◽  
Kai Qin ◽  
...  
Keyword(s):  
Object Recognition ◽  
High Resolution ◽  
Feature Vector ◽  
Dimensional Space ◽  
Digital Elevation Models ◽  
Three Dimensional ◽  
Slope Aspect ◽  
Digital Elevation ◽  
Great Possibility ◽  
High Level

High-resolution digital elevation models (DEMs) and its derivatives (e.g., curvature, slope, aspect) offer a great possibility of representing the details of Earth’s surface in three-dimensional space. Previous research investigations concerning geomorphological variables and region-level features alone cannot precisely characterize the main structure of landforms. However, these geomorphological variables are not sufficient to represent a complex landform object’s whole structure from a high-resolution DEM. Moreover, the amount of the DEM dataset is limited, including the landform object. Considering the challenges above, this paper reports an integrated model called the bag of geomorphological words (BoGW), enabling automatic landform recognition via integrating point and linear geomorphological variables, region-based features (e.g., shape, texture), and high-level landform descriptions. First, BoGW semantically characterizes the composition of geomorphological variables and meaningful parcels of each type of landform. Based on a landform’s semantics, the proposed method then integrates geomorphological variables and region-level features (e.g., shape, texture) to create the feature vector for the landform. Finally, BoGW classifies a region derived from high-resolution DEM into a predefined type of landform by the feature vector. The experimental results on crater and cirque detection indicated that the proposed BoGW could support landform object recognition from high-resolution DEMs.

scholarly journals Investigating the Impact of Digital Elevation Models on Sentinel-1 Backscatter and Coherence Observations

2020 ◽  
Vol 12 (18) ◽  
pp. 3016
Author(s):  
Ignacio Borlaf-Mena ◽  
Maurizio Santoro ◽  
Ludovic Villard ◽  
Ovidiu Badea ◽  
Mihai Andrei Tanase
Keyword(s):  
Remote Sensing ◽  
Laser Scanning ◽  
Digital Elevation Models ◽  
Shuttle Radar Topography Mission ◽  
Synthetic Aperture ◽  
Mountainous Regions ◽  
Aerial Laser Scanning ◽  
Digital Elevation ◽  
The Difference ◽  
The Impact

Spaceborne remote sensing can track ecosystems changes thanks to continuous and systematic coverage at short revisit intervals. Active remote sensing from synthetic aperture radar (SAR) sensors allows day and night imaging as they are not affected by cloud cover and solar illumination and can capture unique information about its targets. However, SAR observations are affected by the coupled effect of viewing geometry and terrain topography. The study aims to assess the impact of global digital elevation models (DEMs) on the normalization of Sentinel-1 backscattered intensity and interferometric coherence. For each DEM, we analyzed the difference between orbit tracks, the difference with results obtained with a high-resolution local DEM, and the impact on land cover classification. Tests were carried out at two sites located in mountainous regions in Romania and Spain using the SRTM (Shuttle Radar Topography Mission, 30 m), AW3D (ALOS (Advanced Land Observation Satellite) World 3D, 30 m), TanDEM-X (12.5, 30, 90 m), and Spain national ALS (aerial laser scanning) based DEM (5 m resolution). The TanDEM-X DEM was the global DEM most suitable for topographic normalization, since it provided the smallest differences between orbital tracks, up to 3.5 dB smaller than with other DEMs for peak landform, and 1.4–1.9 dB for pit and valley landforms.

On computing topographic characteristics of a mountainous catchment

1981 ◽  
Vol 11 (4) ◽  
pp. 768-774 ◽  
Author(s):  
Stanislaw J. Tajchman
Keyword(s):  
Land Surface ◽  
Three Dimensional ◽  
Mountain Regions ◽  
Topographic Analysis ◽  
Mountainous Catchment ◽  
Surface Configuration ◽  
Mountain Catchment ◽  
Topographic Characteristics ◽  
Automatic Reading ◽  
Three Dimensional Coordinate

This report provides a theory and results of its application for a topographic analysis of a mountain catchment in the Appalachian Mountains, U.S.A. The catchment was divided into triangular segments ([Formula: see text]; 1 acre = 0.405 ha) that were analyzed in the three-dimensional coordinate system; topographic parameters of each triangle were computed and their distribution was represented by isolines. Areas included in specified ranges of inclination and azimuth are given in a tabular form in hectares, and they can be located on maps with isolines of azimuth and inclination.The average gradient of slope inclination is greater on northeast- and north-facing slopes (0.32°/m) than on southwest- and south-facing slopes (0.17°/m).The method has potential for application in land ecological, hydrological, and meteorological studies where a mathematical description of land-surface configuration is needed. The development of a system for automatic reading the coordinates from maps and storing them for computer processing would bring nearer the possibility of using this method for detailed biogeophysical analyses of large mountain regions.

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