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Recently updated Collect Earth to v 1.21.8 and noticed that sometimes, the Google Earth Engine (GEE) application (no sign-in) loads an additional widget that shows the temporal segmentation output from Continuous Change Detection and Classification (CCDC) on the Normalized Difference Fraction Index (NDFI). This is a great additional feature that supported the validation, but it only shows in a minority of cases. I am curious to know what affects when it shows up. Does the spatial resolution of the sample assessment unit matter? Does it only show when there are enough valid observations across the Landsat archive? Are there any resources that I can refer to know more about how CCDC is parameterized for use in Collect Earth (e.g., segmentation parameters)? I wasn't able to find any, so any help would be greatly appreciated. Here is an example screenshot of the CCDC plot. LINK: https://ibb.co/4ZLT2Dwz Wasn't able to attach the picture in-line due to low rep points. Thanks! |
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The CCDC widget should generally appear for all plots. However, processing images with the CCDC algorithm is computationally heavy, which can cause the graph to take longer to load—typically between 15 to 30 seconds after the rest of the graphs have been displayed. If you wait a little longer, you should see the graph appear below the Burned Area monthly data section. Examples of Calling the Collect Earth Integrated GEE AppHere are some example links demonstrating how the Collect Earth integrated GEE App is called when a plot is clicked: Important NoteThe interpreter should use the CCDC results as additional support for assessment. The algorithm may not detect all land-use changes present in the plots. For example, certain types of changes may not be captured effectively by the CCDC algorithm. If you are interested in using your own algorithm or customizing the GEE App displayed in Collect Earth, feel free to let us know. We can guide you through the process, although it can be a bit complex right now. |
