July 11 2017
Due to the USGS transition to Landsat Collection 1, the Landsat collections in Earth Engine are in various states of completeness. Specifically, since May 1, the USGS has stopped producing pre-collection data. As a result, the old Landsat image collections in Earth Engine can no longer be updated with new imagery. We have successfully downloaded all of the Collection 1 Tier 1 data for Landsat 5, 7 and 8, and have started ingesting the Tier 2 data. See Landsat Collections page for more info.
Sentinel-2 surface reflectance is not yet available. We are waiting for the results of the ESA Atmospheric Correction Inter-comparison Exercise to provide guidance on the best atmospheric correction method for S2 data.
August 8 2017
- The NSIDC datasets (MOD10A1 and MYD10A1) are not currently being updated due to interoperability issues with the NSIDC authentication.
October 1 2017
- Since transition to Landsat Collection 1, the old pre-collection Surface Reflectance (LANDSAT/LC8_SR etc) is not being updated. Users should switch to the new Collection 1 Surface Reflectance (LANDSAT/LC08/C01/T1_SR etc)
October 2 2017
- In order to save disk space, Sentinel-1 GRD preprocessing converts float32 values to 2-byte unsigned integers and, to avoid losing precision, only keeps the middle 99th percentile of values. This has the effect of discarding very bright outliers. However, these very high values are of interest to some researchers. We are planning to reprocess Sentinel-1 data, keeping all floats unchanged.
- We apply geometric terrain correction (orthorectification) to GRD images. Ideally, they should also undergo radiometric terrai correction (terrain flattening), but we are still working on finding the best way to do this.
- Sentinel-1 SLC data cannot currently be ingested, as Earth Engine does not support images with complex values due to inability to average them during pyramiding without losing phase information.