Rescale
rescale-functions rescale
syntax
- rescale(a, min, max)
definition
rescale(a, min, max) scales the attribute a between the literal / parameter min value and the literal / parameter max value.
The relative differences between the values in the new distribution are similar to the original distribution.
The resulting attribute has a new values-unit and the same domain-unit as attribute a.
description
To avoid rounding off errors in the rescale calculation, use a float32 of float64 value-type for the a, min and max arguments.
Be cautious in using rescales. The values unit / metric of the original attribute get’s lost, less checks can be applied and the results become more difficult to interpret.
conditions
The value type of attribute a and literal / parameter min and max must match.
example
attribute<float32> rescale_NrInh (City) := rescale(City/NrInhabitants, 0f, 1f);
| City/NrInhabitants | rescale_nrInh |
|---|---|
| 550 | 1 |
| 525 | 0.93 |
| 300 | 0.33 |
| 500 | 0.87 |
| 200 | 0.07 |
| 175 | 0 |
| null | null |
domain City, nr of rows = 7