An improved topographic database for King George Island: compilation, application and outlook

2001 ◽  
Vol 13 (1) ◽  
pp. 41-52 ◽  
Author(s):  
Matthias Braun ◽  
Jefferson C. Simões ◽  
Steffen Vogt ◽  
Ulisses F. Bremer ◽  
Norbert Blindow ◽  
...  

A new topographic database for King George Island, one of the most visited areas in Antarctica, is presented. Data from differential GPS surveys, gained during the summers 1997/98 and 1999/2000, were combined with up to date coastlines from a SPOT satellite image mosaic, and topographic information from maps as well as from the Antarctic Digital Database. A digital terrain model (DTM) was generated using ARC/INFO GIS. From contour lines derived from the DTM and the satellite image mosaic a satellite image map was assembled. Extensive information on data accuracy, the database as well as on the criteria applied to select place names is given in the multilingual map. A lack of accurate topographic information in the eastern part of the island was identified. It was concluded that additional topographic surveying or radar interferometry should be conducted to improve the data quality in this area. In three case studies, the potential applications of the improved topographic database are demonstrated. The first two examples comprise the verification of glacier velocities and the study of glacier retreat from the various input data-sets as well as the use of the DTM for climatological modelling. The last case study focuses on the use of the new digital database as a basic GIS (Geographic Information System) layer for environmental monitoring and management on King George Island.

2007 ◽  
Vol 11 (1) ◽  
pp. 516-531 ◽  
Author(s):  
S. M. Crooks ◽  
P. S. Naden

Abstract. This paper describes the development of a semi-distributed conceptual rainfall–runoff model, originally formulated to simulate impacts of climate and land-use change on flood frequency. The model has component modules for soil moisture balance, drainage response and channel routing and is grid-based to allow direct incorporation of GIS- and Digital Terrain Model (DTM)-derived data sets into the initialisation of parameter values. Catchment runoff is derived from the aggregation of components of flow from the drainage module within each grid square and from total routed flow from all grid squares. Calibration is performed sequentially for the three modules using different objective functions for each stage. A key principle of the modelling system is the concept of nested calibration, which ensures that all flows simulated for points within a large catchment are spatially consistent. The modelling system is robust and has been applied successfully at different spatial scales to three large catchments in the UK, including comparison of observed and modelled flood frequency and flow duration curves, simulation of flows for uncalibrated catchments and identification of components of flow within a modelled hydrograph. The role of such a model in integrated catchment studies is outlined.


2015 ◽  
Vol 28 (2) ◽  
pp. 135-149 ◽  
Author(s):  
U. Falk ◽  
H. Gieseke ◽  
F. Kotzur ◽  
M. Braun

AbstractChanges of glaciers and snow cover in polar regions affect a wide range of physical and ecosystem processes on land and in the adjacent marine environment. In this study, we investigated the potential of 11-day repeat high-resolution satellite image time series from the TerraSAR-X mission to derive glaciological and hydrological parameters on King George Island, Antarctica, between 25 October 2010 and 19 April 2011. The spatial pattern and temporal evolution of snow cover extent on ice-free areas can be monitored using multi-temporal coherence images. Synthetic aperture radar (SAR) coherence is used to map glacier extent of land-terminating glaciers with an average accuracy of 25 m. Multi-temporal SAR colour composites identify the position of the late summer snow line at ~220 m a.s.l. Glacier surface velocities are obtained from intensity feature-tracking. Surface velocities near the calving front of Fourcade Glacier were up to 1.8±0.01 m d-1. Using an intercept theorem based on fundamental geometric principles together with differential GPS field measurements, the ice discharge of Fourcade Glacier was estimated at 20 700±5500 m3 d-1 (corresponding to ~19±5 kt d-1). The rapidly changing surface conditions on King George Island and the lack of high-resolution digital elevation models for the region remain restrictions for the applicability of SAR data and the precision of derived products. Supplemental data are available at http://dx.doi.org/10.1594/PANGAEA.853954.


2012 ◽  
Vol 92 (4) ◽  
pp. 51-62
Author(s):  
Ivana Badnjarevic ◽  
Miro Govedarica ◽  
Dusan Jovanovic ◽  
Vladimir Pajic ◽  
Aleksandar Ristic

This research aims to describe the analysis of geoinformation technologies and systems and its usage in detection of terrain slope with reference to timely detection and mapping sites with a high risk of slope movement and activation of landslides. Special attention is referred to the remote sensing technology and data acquisition. In addition to acquisition, data processing is performed: the production of digital terrain model, calculating of the vegetation index NDVI (Normalized Difference Vegetation Index) based on satellite image and analyses of pedology maps. The procedures of processing the satellite images in order to identify locations of high risk of slope processes are described. Several factors and identifiers are analyzed and used as input values in automatic processing which is performed through a unique algorithm. Research results are presented in raster format. The direction of further research is briefly defined.


1997 ◽  
Vol 24 ◽  
pp. 314-319 ◽  
Author(s):  
Frank M. Jacobsen ◽  
Wilfred H. Theakstone

Recent developments of global positioning systems (GPS) have provided opportunities for rapid and frequent glacier mapping. The speed and accuracy of GPS techniques make them particularly suitable for repeated glacier mapping. Using two receivers in differential mode provides very high accuracy. In July 1995, a kinematic differential GPS survey of Austre Okstindbreen, one of the glaciers in the Norwegian national programme of mass-balance studies, provided three-dimensional positions of 2228 points in less than 6.5 h. Handling the data in a geographic information system permitted construction of a triangular irregular network digital terrain model (TIN DTM), which could be compared with TIN DTMs constructed from 1981 and 1993 surveys based on aerial photogrammetry and electronic distance measurement, respectively. A TIN DTM has advantages over the more usual grid-based DTM, which incorporates many interpolated values, although interpolation also is necessary if contours are to be derived from a TIN model. The aspect and gradient of triangular facets in the 1995 DTM have been used to produce a map which has considerable potential for detailed energy-balance studies of the glacier’s accumulation area.


Author(s):  
O. Yazidi Alaoui ◽  
S. Hamdoune ◽  
H. Zili ◽  
H. Boulassal ◽  
M. Wahbi ◽  
...  

Abstract. Mobile networks carrier gather and accumulate in their database system a considerable volume of data, that carries geographic information which is crucial for the growth of the company. This work aimed develop a prototype called Spatial On -Line Analytic Processing (SOLAP) to carry out multidimensional analysis and to anticipate the extension of the area of radio antennas.To this end, the researcher started by creating a Data warehouse that allows storing Big Data received from the Radio antennas. Then, doing the OLAP(online analytic processing) in order to perform multidimensional Analysis which used through GIS to represent the Data in different scales in satellite image as a topographic background). As a result, this prototype enables the carriers to receive continuous reports on different scales (Town, city, country) and to identify the BTS that works and performs well or shows the rate of its working (the way behaves) its pitfalls. By the end, it gives a clear image on the future working strategy respecting the urban planning, and the digital terrain model (DTM).


2021 ◽  
Author(s):  
Jan Hackenberg ◽  
Kim Calders ◽  
Miro Demol ◽  
Pasi Raumonen ◽  
Alexandre Piboule ◽  
...  

The here-on presented SimpleForest is written in C++ and published under GPL v3. As input data SimpleForest utilizes forestry scenes recorded as terrestrial laser scan clouds. SimpleForest provides a fully automated pipeline to model the ground as a digital terrain model, then segment the vegetation and finally build quantitative structure models of trees (QSMs) consisting of up to thousands of topologically ordered cylinders. These QSMs allow us to calculate traditional forestry metrics such as diameter at breast height, but also volume and other structural metrics that are hard to measure in the field. Our volume evaluation on three data sets with destructive volumes show high prediction qualities with concordance correlation coefficient CCC (r2 adj.) of 0.91 (0.87), 0.94 (0.92) and 0.97 (0.93) for each data set respectively. We combine two common assumptions in plant modeling The sum of cross sectional areas after a branch junction equals the one before the branch junction (Pipe Model Theory) and Twigs are self-similar (West, Brown and Enquist model). As even sized twigs correspond to even sized cross sectional areas for twigs we define the Reverse Pipe Radius Branchorder (RPRB) as the square root of the number of supported twigs. The prediction model radius = B 0 ∗ RP RB relies only on correct topological information and can be used to detect and correct overestimated cylinders. In QSM building the necessity to handle overestimated cylinders is well known. The RPRB correction performs better with a CCC (r2 adj.) of 0.97 (0.93) than former published ones 0.80 (0.88) and 0.86 (0.85) in our validation. We encourage forest ecologists to analyze output parameters such as the GrowthVolume published in earlier works, but also other parameters such as the GrowthLength, VesselVolume and RPRB which we define in this manuscript.


1997 ◽  
Vol 24 ◽  
pp. 314-319 ◽  
Author(s):  
Frank M. Jacobsen ◽  
Wilfred H. Theakstone

Recent developments of global positioning systems (GPS) have provided opportunities for rapid and frequent glacier mapping. The speed and accuracy of GPS techniques make them particularly suitable for repeated glacier mapping. Using two receivers in differential mode provides very high accuracy. In July 1995, a kinematic differential GPS survey of Austre Okstindbreen, one of the glaciers in the Norwegian national programme of mass-balance studies, provided three-dimensional positions of 2228 points in less than 6.5 h. Handling the data in a geographic information system permitted construction of a triangular irregular network digital terrain model (TIN DTM), which could be compared with TIN DTMs constructed from 1981 and 1993 surveys based on aerial photogrammetry and electronic distance measurement, respectively. A TIN DTM has advantages over the more usual grid-based DTM, which incorporates many interpolated values, although interpolation also is necessary if contours are to be derived from a TIN model. The aspect and gradient of triangular facets in the 1995 DTM have been used to produce a map which has considerable potential for detailed energy-balance studies of the glacier’s accumulation area.


2019 ◽  
Vol 632 ◽  
pp. L4 ◽  
Author(s):  
F. Preusker ◽  
F. Scholten ◽  
S. Elgner ◽  
K.-D. Matz ◽  
S. Kameda ◽  
...  

A high-resolution 3D surface model, map-projected to a digital terrain model (DTM), and precisely ortho-rectified context images (orthoimages) of MASCOT landing site area are important data sets for the scientific analysis of relevant data that have been acquired with MASCOT’s image camera system MASCam and other instruments (e.g., the radiometer MARA and the magnetometer MASMag). We performed a stereo-photogrammetric (SPG) analysis of 1050 images acquired from the Hayabusa2 Optical Navigation Camera system (ONC) during the asteroid characterization phase and the MASCOT release phase in early October 2018 to construct a photogrammetric control point network of asteroid (162173) Ryugu. We validated existing rotational parameters for Ryugu and improved the camera orientation (position and pointing) of the ONC images to decimeter accuracy using SPG bundle block adjustment. We produced a high-resolution DTM of the entire MASCOT landing site area. Finally, based on this DTM, a set of orthoimages from the highest-resolution ONC images around MASCOT’s final rest position complements the results of this analysis.


2011 ◽  
Vol 38 (2) ◽  
pp. 132
Author(s):  
Guilherme Garcia De OLIVEIRA ◽  
Dejanira Luderitz SALDANHA ◽  
Laurindo Antonio GUASSELLI

The study aims at developing models for the spatialization and forecasting of floods in the urban area of São Sebastião do Caí, RS, Brazil. For the calculation of return period (RP), and in order to analyze the seasonality of floods, streamflow data from the station located in the city were used. However, for the development of a mathematical model for flood forecasting, the time series of a station upstream was also used in order to perform a regression with the quotas recorded in both seasons. For the identification of flood plains, a digital terrain model was produced based on elevation data in scales between 1:2,000 and 1:10,000. The QuickBird satellite image (spatial resolution of 0.61 m) was used only for the spatialization of the land use and land cover reached by each flood scenario. Mapping and 3D simulation of the areas affected by flooding were obtained for RP of 2, 5, 10 and 30 years. The following results are most significant: i) the river water level rises between 9.28 m and 11.98 m for RP of 2 to 30 years; ii) along the historical series, 75% of floods have occurred between June and October; iii) the mathematical model for flood forecasting showed an average error of 0.72 m, and the accuracy varies between 0.62 m and 1.84 m, according to the expected magnitude; iv) it was observed that 93 hectares of urban area in São Sebastião do Caí are hit by floods with a RP of 30 years (23% of the urban area); v) modelling of a recent flood event dated of 24/09/2007 has resulted in similar values for the simulated and observed flooded area.


2019 ◽  
Vol 11 (17) ◽  
pp. 2052 ◽  
Author(s):  
Roland Perko ◽  
Hannes Raggam ◽  
Peter M. Roth

In this work, we introduce an end-to-end workflow for very high-resolution satellite-based mapping, building the basis for important 3D mapping products: (1) digital surface model, (2) digital terrain model, (3) normalized digital surface model and (4) ortho-rectified image mosaic. In particular, we describe all underlying principles for satellite-based 3D mapping and propose methods that extract these products from multi-view stereo satellite imagery. Our workflow is demonstrated for the Pléiades satellite constellation, however, the applied building blocks are more general and thus also applicable for different setups. Besides introducing the overall end-to-end workflow, we need also to tackle single building blocks: optimization of sensor models represented by rational polynomials, epipolar rectification, image matching, spatial point intersection, data fusion, digital terrain model derivation, ortho rectification and ortho mosaicing. For each of these steps, extensions to the state-of-the-art are proposed and discussed in detail. In addition, a novel approach for terrain model generation is introduced. The second aim of the study is a detailed assessment of the resulting output products. Thus, a variety of data sets showing different acquisition scenarios are gathered, allover comprising 24 Pléiades images. First, the accuracies of the 2D and 3D geo-location are analyzed. Second, surface and terrain models are evaluated, including a critical look on the underlying error metrics and discussing the differences of single stereo, tri-stereo and multi-view data sets. Overall, 3D accuracies in the range of 0 . 2 to 0 . 3 m in planimetry and 0 . 2 to 0 . 4 m in height are achieved w.r.t. ground control points. Retrieved surface models show normalized median absolute deviations around 0 . 9 m in comparison to reference LiDAR data. Multi-view stereo outperforms single stereo in terms of accuracy and completeness of the resulting surface models.


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