Discussion
SEPAL vs. GEE
SEPAL | GEE |
pro - quick to learn | con - takes more time to learn |
pro - no programming experience needed | con - requires understanding of programming basics |
con - complicated workflow using multiple different tools | pro - simple worflow that can be done in 2 scripts |
con - limited choices for input data | pro - can import any data sets from personal computer or GEE Data Catalogue (PALSAR, Harmonized Landsat Sentinel) |
con - limited choices for pre- and post-processing | pro - can access all pre- and post-processing GEE tools (smoothing, cloud masking, calculating indices) |
con - limited options for altering model parameters | pro - many options for altering model parameters (multiprobability mode, variable importance) |
con - difficult to rerun to test out different versions | pro - easy to rerun to test out different versions |
Ways to Improve Accuracy
1. Preprocessing
- increase the number of training and testing points
- overall and/or using a stratified approach with more points in classes with low accuracies
- change or combine cloud masking strategies
- composite imagery for more than 1 year
- merge or separate classes of interest (e.g. one combined forest class instead of separated forest classes, separate wetlands class)
2. Model Development
- add and remove predictor variables based on variable importance and accuracy (e.g. different combinations of imagery sources or indices)
- increase the number of trees in the random forest model
- generate more training points in the areas of highest uncertainty and retrain the model with the addition of these new points
3. Postprocessing
- change smoothing functions
- overlay with hand-digitized data