Incremental harvesting model of distributed geospatial data registry center based on CSW

This paper aims at providing an incremental harvesting model used in distributed geospatial data registry centers, which is more efficiency than overall harvesting model. Compared with overall harvesting model, it pays more attention to the incremental items which are created, modified and deleted. As incremental items are only a few of the totals, they save the time on fetching and processing changed items. The whole harvest process is mainly composed of three steps. Firstly, retrieve time and incremental items from remote server. Secondly, processing fetched items with UUID. Finally, post updates and log the harvest time obtained from step 1. The model is implemented by extending CSW protocol and GeoNetwork. The experiment of comparing the time cost by incremental harvesting model and overall harvesting model shows that incremental harvesting model is much more efficient and applicable.