Acta Geodaetica et Cartographica Sinica ›› 2019, Vol. 48 ›› Issue (2): 226-237.doi: 10.11947/j.AGCS.2019.20180216

• Cartography and Geoinformation • Previous Articles     Next Articles

Run length coding and efficient compression of hexagonal raster data supported by Gosper curve

XIN Rui, AI Tinghua   

  1. School of Resource and Environmental Sciences, Wuhan University, Wuhan 430079, China
  • Received:2018-05-07 Revised:2018-10-31 Online:2019-02-20 Published:2019-03-02
  • Supported by:

    The National Natural Science Foundation of China (No. 41531180);The National Key Research and Development Program of China (No. 2017YFB0503500);The National High Technology Research and Development Program of China (863 Program) (No. 2015AA124103)

Abstract:

By introducing the Gosper curve into hexagonal grid, a new form of run length coding is established.Based on this, the lossless compression coding and loss compression coding of raster data are carried out. First, the bidirectional correspondence between Gosper curve and hexagonal raster data is established to provide guidance and support for data coding. Then, the Gosper coding value of each raster cell is determined. The lossless compression is realized by making run length coding for the coding set of target region. On this basis, loss compression utilizes the good spatial aggregation of Gosper curve to fuse adjacent regions and eliminate details. Under certain threshold constraints and following the direction of Gosper curve, the number of coding objects can be reduced by changing the ownership of partial raster units.The data is recoded through run length coding to simply the coding of target region. At last, the validity of this method is verified by experiment. Based on the realization of compression coding methods, data compression of multi-resolution and different fusion thresholds is explored.In addition, it is compared with other methodes to highlight its advantages.

Key words: grid coding, run length coding, data compression, hexagonal grids, Gosper curve

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