scholarly journals Visual mining of moving flock patterns in large spatio-temporal data sets using a frequent pattern approach

2014 ◽  
Vol 28 (10) ◽  
pp. 2013-2029 ◽  
Author(s):  
Ulanbek Turdukulov ◽  
Andres Oswaldo Calderon Romero ◽  
Otto Huisman ◽  
Vasilios Retsios
2020 ◽  
pp. 42-49
Author(s):  
І. Savchyn ◽  
◽  
Ye. Shylo ◽  

Due to global warming, the glaciers and ice systems of Antarctica and the Antarctic Peninsula have been significantly changing in shape and size in recent decades. Therefore, to control, forecast and prevent such processes, it is necessary to constantly monitor and analyse changes in the basic parameters of glaciers and ice systems. This paper proposes a study of changes in the area of ice caps located on the Galindez, Winter and Skua islands (Argentine Islands, West Antarctica). The study is based on the integration of different spatio-temporal datasets into a single system for retrospective geographical monitoring of changes in the area of Galindez, Winter and Skua islands ice caps. The system for integrating space-time datasets is the UTM coordinate system (zone 20, South). Using transformed archival cartographic materials, as well as recently obtained orthophotos, the boundaries of the glaciers in different periods of research were digitized. Based on the identified boundaries, the significance of changes in the area of island glaciers, as well as the rate of their change during 1935–2019, were determined. Based on the integration of different spatio-temporal datasets into a single system, retrospective-geographical monitoring of changes in icecaps area during 1935–2019 was performed. The ice caps were found to be experiencing systematic decrease in area with average linear rate of decrease from –0.30%/year to –0.37%/year. A detailed analysis of all integrated spatio-temporal data sets including determination of the cause of changes in the area of the Galindez, Winter and Skua islands' ice caps is a promising topic for further research.


Polar Record ◽  
2007 ◽  
Vol 43 (4) ◽  
pp. 331-343 ◽  
Author(s):  
Franz J. Meyer

ABSTRACTThis paper describes a new technique simultaneously to estimate topography and motion of polar glaciers from multi-temporal SAR interferograms. The approach is based on a combination of several SAR interferograms in a least-squares adjustment using the Gauss-Markov model. For connecting the multi-temporal data sets, a spatio-temporal model is proposed that describes the properties of the surface and its temporal evolution. Rigorous mathematical modelling of functional and stochastic relations allows for a systematic description of the processing chain. It is also an optimal tool to set parameters for the statistics of every individual processing step, and the propagation of errors into the results. Within the paper theoretical standard deviations of the unknowns are calculated depending on the configuration of the data sets. The influence of gross errors in the observations and the effect of non-modelled error sources on the unknowns are estimated. A validation of the approach based on real data concludes the paper.


2020 ◽  
Author(s):  
Jan Schulte ◽  
Laura Helene Zepner ◽  
Stephan Mäs ◽  
Simon Jirka ◽  
Petra Sauer

<p><span>Over the last few years, a broad range of open data portals has been set-up. The aim of these portals is to improve the discoverability of open data resources and to strengthen the re-use of data generated by public agencies as well as research activities.</span></p><p><span>Often, such open data portals offer an immense amount of different types of data that may be relevant for a user. Thus, in order to facilitate the efficient and user-friendly exploration of available data sets, it is essential to visualize the data as quickly and easily as possible. While the visuali</span><span>z</span><span>ation of static data sets is already well covered, selecting appropriate visuali</span><span>z</span><span>ation approaches for potentially highly-dynamic spatio-temporal data sets is often still a challenge.</span></p><p><span>Within our contribution, we will introduce a preliminary study conducted by the mVIZ project which is funded by the German Federal Ministry of Transport and Digital Infrastructure as part of the mFUND programm. This project </span><span>introduces</span> <span>a </span><span>methodology to support the selection and creation of user-friendly visualizations for data discoverable via the open data portals such as the mCLOUD. During this process, specific consideration </span><span>are </span><span>given to properties and metadata of the datasets as input for a decision workflow to suggest appropriate visuali</span><span>z</span><span>ation types. A resulting guideline will describe the methodology and serve as a basis for the conception, extension or improvement of visualization tools or for their further development and integration into open data portals.</span></p><p><span>The project focuses particularly on the creation of an inventory of open spatiotemporal data in open data portals as well as an overview of available visualization and analysis tools, the development of a methodology for selecting appropriate visualizations for the spatio-temporal data, and the development of a demonstrator for supporting the visualization of selected data sets.</span></p>


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