Digital maps can best stored and distributed electronically using compressed raster image formats.We introduce as to rage system for the

map images that supports compact storage size,decompression of partial image,and smooth transitions between various scales.The main

objective of the proposed storage system is to provide map images for real-time applications that use portable devices with low memory and

computing resources.Compact storage size is achieved by dividing the maps into binary layers,which are compressed using context-based

statistical modeling and arithmetic coding.Partial image decompression is supported by tiling the image into block sand implementing direct

access to the compressed blocks.In this paper,we give overview of the system architecture,describe the compression technique,and discuss

implementation aspects.Experimental result sare given both in terms of compression ratio sand image retrieval timings.