In this paper

a real-time compression algorithm for spatial data was proposed to improve the quality of spatial information service.The algorithm includes two key points.Firstly

the coding rules of RLE were developed.Only if the number of repeated byte reaches to 3or more

the stream segment is allowed to code with the two bytes

one is the repeated number

another is the repeated byte.Otherwise

the stream segment is output directly after the number of uncoded bytes.Secondly

self-adaptive interval run length coding was put forward.The intervals of 24

16and 4are used to test the compression ratio of the origin spatial data stream.The interval of the highest compression ratio is used as the final coding strategy.It was proved that the algorithm of this paper can be used to the spatial data transmission and make real-time transmission of spatial data possible.