AI-generated Key Takeaways
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The Vegetation Change Tracker (VCT) automatically reconstructs forest disturbance history using dense Landsat time series stacks.
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VCT identifies disturbances by analyzing changes in spectral indices like NDVI, dNBR, and UD composite over time.
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The output provides a per-pixel disturbance magnitude for each year within the analyzed Landsat time series.
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Users can customize parameters like maximum UD composite value and minimum NDVI for forest detection.
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VCT requires input Landsat time series collections with specific bands, including B3, B4, B5, B7, thermal, NDVI, DNBR, and COMP.
The output is a 2D array per pixel containing 6 rows x N years. The output rows contain: input years, VCT landcover mask, magnitude in term of the UD composite, magnitude of distubance in B4, magnitude of distubance in NDVI, magnitude of distubance in dNBR.
See: Huang, C., Goward, S.N., Masek, J.G., Thomas, N., Zhu, Z. and Vogelmann, J.E., 2010. An automated approach for reconstructing recent forest disturbance history using dense Landsat time series stacks. Remote Sensing of Environment, 114(1), pp.183-198.
| Usage | Returns |
|---|---|
ee.Algorithms.TemporalSegmentation.VCT(timeSeries, landCover, maxUd, minNdvi, forThrMax, nYears) | Image |
| Argument | Type | Details |
|---|---|---|
timeSeries | ImageCollection | Collection from which to extract VCT disturbances, containing the bands: B3, B4, B5, B7, thermal, NDVI, DNBR, and COMP. This collection is expected to contain 1 image for each year, sorted by time. |
landCover | ImageCollection | Collection from which to extract VCT masks. This collection is expected to contain 1 image for each image in the timeSeries, sorted by time. |
maxUd | Float, default: 4 | Maximum Z-score composite value for detecting forest. |
minNdvi | Float, default: 0.45 | Minimum NDVI value for forest. |
forThrMax | Float, default: 3 | Maximum threshold for forest. |
nYears | Integer, default: 30 | Maximum number of years. |