ALOS Kyoto & Carbon Mosaics by JAXA#

This module was adapted to the SEPAL environment from this script by Vollrath.

Designed on top of the interactive framework sepal_ui, this module allows users to extract ALOS K&C mosaics.

Necessary inputs include:

  • an area of interest (AOI)

  • a year

  • select filters

The user will be able to display the mosaic in an interactive map and export it as a Google Earth Engine (GEE) asset and/or SEPAL .tif file.

The three-step process is described in the sections below, as well as presented in the following video tutorial.

Select an AOI#

Using the provided AOI selector, select an AOI of your choice between the different methods available in the tool. We provide three administrative descriptors (from level 0 to 2) and three custom shapes (drawn directly on the map, asset or shapefile).

https://raw.githubusercontent.com/lecrabe/alos_mosaics/main/doc/img/aoi_select.png

AOI selector#

Note

If a custom AOI from a shape or drawing is selected, you will be able to use it directly. The upload to GEE will be launched in the background.

Process mosaic#

In the Process tile, set the different parameters of your mosaic:

  • Year: the year of interest

  • Speckle filter: the speckle filter to use during the process - no filter - refined lee: speckle noise removal technique based on the Lee Filter (for more information, see A.S. Yommy et al.). - Quegan filter: See Quegan et al.

  • Shadow masking: activate or deactivate shadow masking

  • Db: whether or not to scale the output to Db

After setting your parameters, select the button. The dataset will be automatically sent to the Vizualization tile.

https://raw.githubusercontent.com/lecrabe/alos_mosaics/main/doc/img/parameters.png

Dataset parameters#

Display dataset#

The dataset is automatically displayed on the interactive map, allowing you to zoom in and out.

Choose from three diplay options:

  • Backscatter RGB (HH, HV, HH/HV power ratio)

  • Radar Forest Degradation Index (RFDI, Mitchard et al., 2012)

  • Forest/Non-Forest

https://raw.githubusercontent.com/lecrabe/alos_mosaics/main/doc/img/display.png

Display information#

Export dataset#

When you’re satified with the information displayed, it can be exported for further use in GIS software or in a GEE process. The tool provides two main exportation options: as an asset (in GEE) or a .tif file (in SEPAL).

Both use the GEE export system and share the same set of parameters:

  • Export backscatter (HH, HV, HH/HV power ratio)

  • Export/add Radar Forest Degradation Index (RFDI, Mitchard et al., 2012)

  • Export/add GLCM texture layers for HH and HV polarizations (Variance, Homogeneity, Dissimilarity)

  • Export/add auxiliary metadata layers (Acq. Date, LIA, QA layer)

  • Export K&C forest/non-forest map (separate file)

  • Set the resolution as an integer number

Note

The default export parameters include: 25 metre resolution with backscatter and RFDI.

https://raw.githubusercontent.com/lecrabe/alos_mosaics/main/doc/img/export.png

Export#

Attention

When exporting images to SEPAL, do not quit the application until the downloading process is complete.