2014-05-19 15:08 GMT+02:00 Glynn Clements <[email protected]>: > r60346 implements the following logic: > > For any aggregate, there are 2 factors affecting the output type: > > 1. Whether the input map is integer or floating-point. > 2. Whether the weighted or unweighted version of the aggregate is used. > > These combine to create 4 possibilities: > > type integer integer float float > weighted no yes no yes > > average float float float float > median [1] [1] float float > mode integer integer [2] [2] > minimum integer integer float float > maximum integer integer float float > range integer integer float float > stddev float float float float > sum integer float float float > count integer float integer float > variance float float float float > diversity integer integer integer integer > interspersion integer integer integer integer > quart1 [1] [1] float float > quart3 [1] [1] float float > perc90 [1] [1] float float > quantile [1] [1] float float > > [1] For integer input, quantiles may produce float results from > interpolating between adjacent values. > > [2] Calculating the mode of floating-point data is essentially > meaningless. > > With the current aggregates, there are 5 cases: > > 1. Output is always float: average, variance, stddev, quantiles (with > interpolation). > > 2. Output is always integer: diversity, interspersion. > > 3. Output is integer if unweighted, float if weighted: count. > > 4. Output matches input: minimum, maximum, range, mode (subject to > note 2 above), quantiles (without interpolation). > > 5. Output is integer for integer input and unweighted aggregate, > otherwise float: sum.
would be nice to put to the manual I guess. Martin -- Martin Landa * http://geo.fsv.cvut.cz/gwiki/Landa _______________________________________________ grass-dev mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/grass-dev
