The Design And Realization Of Raster Data Engine In Embedded Gis

Embedded equipment exists everywhere, embedded GIS is widely applied at various fields, and then, raster data become one of the most important data sources of embedded GIS. We named these maps the raster data map, which express special geographical elements or phenomena distributing through regular pels array, such as remote sensing image, terrain scan image. Raster data map file's data amount is large, format is multiple, at the same time, embedded system limit its hardware and software resource as few as possible for controlling its cost, volume and energy consuming, this brings trouble for using raster data map in embedded GIS. How to provide an interface to use raster data becomes an important question for embedded GIS, and then,"Raster data engine in embedded GIS", which studied by this treatise, is brought up based on this question.Embedded GIS raster data engine (called EGIS-RDEngine for short hereinafter) is an application interface, which can display, zoom in, zoom out, pan, rotate raster map in embedded system. It conceals raster map file's format, and data's organization and management way, supplies an interface for using raster data, can realize raster map's quickly displaying and browsing, and can combining vector data for commixed displaying, special analysis, and querying. Detailed works as follows:1,Through an integrative organization and management way, builds up a raster database, supplies a data source for embedded GIS.2,Designs the OODM( object oriented data model) based on database's structure, designs GIS's data accessing module and map displaying and controlling module, as GIS's data accessing and map drawing interface.3,Designs the mode of memory management and the strategy of raster data attemperment for embedded GIS, in the limited software and hardware resource surrounding, realizes the raster map's displaying, zooming in, zooming out, panning, and other basal operation.4,Discusses the technique of coordinate matching, puts forward a thought for combining raster data and vector data to display, to query and analyze.5,Develops an embedded geographical information system in VxWorks operation system, validates the designed EGIS-RDEngine's feasibility and usability.This treatise study production are: the first is a data prepare tool which can predeal with raster data and import it to database and run in Windows system, the second is an application interface of raster data, can run in multi embedded systems.