Data structures and operations for geographical information
The topic of this thesis revolves around the organization of geographical information in permanent memory. Our premise is that a recognized and fully documented direct access storage technique called Multidimensional Paging or Multipaging would provide a well balanced storing structure for this cate...
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ndltd-LACETR-oai-collectionscanada.gc.ca-QMM.239452014-02-13T04:03:24ZData structures and operations for geographical informationToussaint, RichardInformation Science.Computer Science.The topic of this thesis revolves around the organization of geographical information in permanent memory. Our premise is that a recognized and fully documented direct access storage technique called Multidimensional Paging or Multipaging would provide a well balanced storing structure for this category of data. Since multipaging uses a multidimensional perspective on the information to allocate it to pages in secondary storage then spatial data, which is fundamentally multidimensional by nature, would surely offer a suitable profile.First, we attempt to evaluate the efficiency of multipaging on static files and to suggest possible modifications to the standard algorithm to better serve spatial data.Our solution to this problem consists in compressing the pages that overflow. Because geographical information is often a representation of occurences of Nature, we hypothesize that Fractal Geometry, which serves to formalize a mathematical description of such elements, could provide the theoretical background to derive an efficient fractal-based compression algorithm. An appreciable improvement is obtained by compressing the pages of the multipaged administrative regions data that exceed their capacity: $ alpha=0.7272$ and $ pi=1.0$.The outcome of these experiments led us to elaborate a mixed system based on two relatively different approaches: multipaging and fractal-based data compression. The first part consisted in the implementation of the standard static multipaging algorithm using a relational database management system named Relix. The other approach was developed using the C programming language to accommodate some particularities of the multipaged spatial data. The preliminary results were encouraging and allowed us to establish the parameters for a more formal implementation. Also, it brought out the limits of the compression method in view of the intended usage of the data. (Abstract shortened by UMI.)McGill UniversityMerrett, T. H. (advisor)1995Electronic Thesis or Dissertationapplication/pdfenalephsysno: 001486464proquestno: MM12281Theses scanned by UMI/ProQuest.All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated.Master of Science (School of Computer Science.) http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=23945 |
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Information Science. Computer Science. Toussaint, Richard Data structures and operations for geographical information |
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The topic of this thesis revolves around the organization of geographical information in permanent memory. Our premise is that a recognized and fully documented direct access storage technique called Multidimensional Paging or Multipaging would provide a well balanced storing structure for this category of data. Since multipaging uses a multidimensional perspective on the information to allocate it to pages in secondary storage then spatial data, which is fundamentally multidimensional by nature, would surely offer a suitable profile. === First, we attempt to evaluate the efficiency of multipaging on static files and to suggest possible modifications to the standard algorithm to better serve spatial data. === Our solution to this problem consists in compressing the pages that overflow. Because geographical information is often a representation of occurences of Nature, we hypothesize that Fractal Geometry, which serves to formalize a mathematical description of such elements, could provide the theoretical background to derive an efficient fractal-based compression algorithm. An appreciable improvement is obtained by compressing the pages of the multipaged administrative regions data that exceed their capacity: $ alpha=0.7272$ and $ pi=1.0$. === The outcome of these experiments led us to elaborate a mixed system based on two relatively different approaches: multipaging and fractal-based data compression. The first part consisted in the implementation of the standard static multipaging algorithm using a relational database management system named Relix. The other approach was developed using the C programming language to accommodate some particularities of the multipaged spatial data. The preliminary results were encouraging and allowed us to establish the parameters for a more formal implementation. Also, it brought out the limits of the compression method in view of the intended usage of the data. (Abstract shortened by UMI.) |
author2 |
Merrett, T. H. (advisor) |
author_facet |
Merrett, T. H. (advisor) Toussaint, Richard |
author |
Toussaint, Richard |
author_sort |
Toussaint, Richard |
title |
Data structures and operations for geographical information |
title_short |
Data structures and operations for geographical information |
title_full |
Data structures and operations for geographical information |
title_fullStr |
Data structures and operations for geographical information |
title_full_unstemmed |
Data structures and operations for geographical information |
title_sort |
data structures and operations for geographical information |
publisher |
McGill University |
publishDate |
1995 |
url |
http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=23945 |
work_keys_str_mv |
AT toussaintrichard datastructuresandoperationsforgeographicalinformation |
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1716644183985356800 |