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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.
[[["Easy to understand","easyToUnderstand","thumb-up"],["Solved my problem","solvedMyProblem","thumb-up"],["Other","otherUp","thumb-up"]],[["Missing the information I need","missingTheInformationINeed","thumb-down"],["Too complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2024-07-13 UTC."],[[["\u003cp\u003eCalculates long-term and short-term trends of a time series, optionally considering a covariate for ratio trends.\u003c/p\u003e\n"],["\u003cp\u003eLong-term trends are determined through linear regression over the entire series, while short-term trends use a windowed minimum approach.\u003c/p\u003e\n"],["\u003cp\u003eOutputs include the long and short-term trends, a t-test for the long-term trend's significance, and a stability test.\u003c/p\u003e\n"],["\u003cp\u003eRequires an evenly spaced time series ImageCollection and an optional covariate ImageCollection.\u003c/p\u003e\n"],["\u003cp\u003eUsers can customize the short-term trend analysis by adjusting the window size.\u003c/p\u003e\n"]]],[],null,["# ee.ImageCollection.formaTrend\n\nComputes 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.\n\n\u003cbr /\u003e\n\nThe 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.\n\n| Usage | Returns |\n|---------------------------------------------------------------|---------|\n| ImageCollection.formaTrend`(`*covariates* `, `*windowSize*`)` | Image |\n\n| Argument | Type | Details |\n|--------------------|--------------------------------|---------------------------------------------------|\n| this: `timeSeries` | ImageCollection | Collection from which to extract trends. |\n| `covariates` | ImageCollection, default: null | Cofactors to use in the trend analysis. |\n| `windowSize` | Integer, default: 6 | Short term trend analysis window size, in images. |"]]
