Suimnary 



250. In this section, measured data were examined for systematic order 

 at the level of directional distribution shapes. Using unimodal distributions 

 where low energy cases were excluded as a basis for examination, it was found 

 that the shapes were readily classified by parameters of directional spread 

 and asymmetry. Similar distributions were observed at all frequencies. 

 Classes with low asymmetry were found to conform reasonably well to a one- 

 parameter mathematical function proposed by Longuet-Higgins , Cartwright, and 

 Smith (1963), at least in the low- to- intermediate ranges of spread. Strongly 

 asymmetric distributions, for which this model could not work well, were found 

 to occur in at least half the observations. 



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