Computes the long and short term trends of a time series or optionally, the trends of the ratio of the time series and a covariate. The long term trend is estimated from the linear term of a regression on the full time series. The short term trend is computed as the windowed minimum over the time series.
The time series and covariate series are expected to contain a single band each, and the time series is expected to be evenly spaced in time. The output is 4 float bands: the long and short term trends, the t-test of the long term trend against the time series, and the Bruce Hansen test of parameter stability.
| Usage | Returns |
|---|---|
ImageCollection.formaTrend(covariates, windowSize) | Image |
| Argument | Type | Details |
|---|---|---|
this: timeSeries | ImageCollection | Collection from which to extract trends. |
covariates | ImageCollection, default: null | Cofactors to use in the trend analysis. |
windowSize | Integer, default: 6 | Short term trend analysis window size, in images. |