Correlation - ObjectVision/GeoDMS GitHub Wiki
Aggregation functions correlation
- corr(a, b)
- corr(a, b, relation)
- corr(a, b) results in the correlation coefficient of attributes a and b.
- corr(a, b, relation) results in the correlation coefficient of attributes a and b, grouped by relation. The domain unit of the resulting attribute is the values unit of the relation.
The value type of the resulting data item is float32 or float64.
- attribute a and b with Numeric value type
- relation with value type of the group CanBeDomainUnit
- The value type of the arguments a and b must match.
- The domain of arguments a, b and relation must match.
1. parameter<float32> corrNrInhabitantsTemp :=
corr(float32(City/NrInhabitants), City/avgDailyTemperature); result = -0.89948
2. attribute<float32> corrNrInhabitantsTempRegion (Region) :=
corr(
float32(City/NrInhabitants)
,City/avgDailyTemperature
,City/RegionNr
);
| City/NrInhabitants | City/avgDailyTemperature | City/Region_rel |
|---|---|---|
| 550 | 12 | 0 |
| 525 | 11 | 1 |
| 300 | null | 2 |
| 500 | 11 | 1 |
| 200 | 14 | 3 |
| 175 | null | null |
| null | 14 | 3 |
domain City, nr of rows = 7
| corrNrInhabitantsTempRegion |
|---|
| null |
| null |
| null |
| null |
| null |
domain Region, nr of rows = 5