Информационная система "Конференции"

Abstracts

The article considers new file formats designed for storage of large amounts of static spatial data. The file format MRG has been designed for storage of large amounts of integer raster data. This format supports fast extraction of raster fragments of different detail levels due to representation of both the most detailed data and grids of lower resolution. A data structure is proposed, which allows not only not to spend additional disk memory for storing rasters of lower resolution, but, conversely, to decrease the overall memory usage. To store effectively the data under consideration an original compression algorithm has been developed, which is especially designed for packing integer difference sequences, and allows not only to increase the compression ratio but also to reduce the compression time (in comparison with the popular data compression library ZLib). A dynamic link library for reading data from MRG files has been developed, which allows to use the information in third-party applications. The software developed for reading MRG files is capable to work under memory usage limit down to 16Mb of RAM. To store effectively vector data an effective technique for representation of static data structures has been developed, which allows to reduce memory expense and shorten the time required to load the data from file. Using the suggested approach has been designed a new file format SMD for representation of static vector maps. An extension of Web-server IIS has been developed, which allows to publish in Internet/Intranet the vector maps, represented in SMD. A map data converters into SMD have been developed for the file formats of GIS Panorama, ArcView and MapInfo. The converters import into SMD files not only the semantic and metric information, but also the information about object presentation. So, for Web-publishing of a vector map stored in one of the above mentioned file formats, it’s enough to convert it into SMD, and the capability to import object presentation allows to obtain the map appearance, which is close to the original one.

Note. Abstracts are published in author's edition

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