Research on the lowest-value cache replacement algorithm of geospatial data in Network GIS
Dongying Zhang · 2012
The network transmission cost of geospatial data is an important factor influencing the quality of network GIS service.The data cache mechanism completes the data response rapidly.In this way,the quality of GIS service has been significantly improved.The commonly used replacement algorithms such as FIFO,LRU,LFU,only take the access time and the access frequency into account,failing to cover the location features of geospatial data.The author proposed a cache replacement algorithm for geospatial data called GDLVF(Lowest Value First Cache Replacement for Geospatial Data) according to the network GIS.Other than the access time and the access frequency,GDLVF also takes the factor of the size and location of geospatial data into consideration.Data distance and valid scope area which are both related with the view scope are used to calculate the value of data.Additionally,the weighted data size is also applied to GDLVF to reduce the influence of the value calculation caused by the data size differences.At the end,an experiment is taken to measure the hit ratio and the bytes hit ratio of GDLVF in 1000Mbps LAN.The research shows that GDLVF is capable to handle well both the request hit ratio and the bytes hit ratio,thus reducing the data transmission network and improving the quality of GIS service significantly.