[GRASS-dev] G7: r.neighbors changes data type from CELL to DCELL

[Martin Landa]

2014-05-19 15:08 GMT+02:00 Glynn Clements <glynn at gclements.plus.com>:
> 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