2141	 Algorithmic Selection of the Best Method for Compressing Map Data Strings	 The best of a dozen different methods for compressing map data is illustrated. The choices are generated by encoding data strings-sequence of like codes-by three methods and in four directions. Relationships are developed between compression alternatives to avoid comparing all of them. The technique has been used to compress data from forest resource maps but is widely applicable to map and photographic data reduction. data compression map storage information retrieval input output run coding data reduction
