Landsat 8 and 9 (from USGS)
Description
Landsat 8 and 9 images are optical and thermal images measured every 8 days, with a resolution of 30 meters. Supported images and levels are:
Optical |
Thermal |
|
Level 1 |
✗ |
✓ |
Level 2 |
✓ |
✓ |
These images are available to download here. Additional information can be found here and here for level 2 products and here for level 1 products.
Usage
To use these images as iota2 input two ways are available:
General sensor
The simplest way is to use one general sensor, called Landsat8USGS. It uses all provided images and processes them identically. chain.l8_usgs_path is the parameter to enable the use of Landsat 8 and 9 products by iota2.
chain:
{
...
l8_usgs_path:"/absolute/path/to/Storage_directory"
...
}
Warning
While simpler to use, this method may introduce processing errors, due to the differing nature of the images: thermal images shouldn’t be processed exactly like optical images.
Differentiated sensors
The ideal way of dealing with Landsat 8 and 9 images is using multiple sensors, one for each type of supported images:
chain:
{
...
l8_usgs_optical_path:"/absolute/path/to/Storage_directory_optical"
l8_usgs_thermal_path:"/absolute/path/to/Storage_directory_thermal"
l8_usgs_infrared_path:"/absolute/path/to/Storage_directory_infrared"
...
}
With:
- Optical:
Level 2 optical products (bands 1 to 7):
["B1", "B2", "B3", "B4", "B5", "B6", "B7"]- Thermal:
Level 2 thermal product (band 10) and emissivity map:
["B10", "EMIS"]
Warning
The use of the emissivity is supported but not activated by default, as it doesn’t seem to add pertinent information.
- Infrared:
Level 1 thermal products (bands 11 and 12):
["B10", "B11"]
Image files can be stored either across multiple different directories or within a single directory (much simpler solution):
└── Storage_directory
├── tile199029
│ ├── LC08_L2SP_199029_20230309_20230320_02_T1
│ │ ├── LC08_L2SP_199029_20230309_20230320_02_T1_SR_B1.TIF # Level 2, band 1 (optical)
│ │ ├── LC08_L2SP_199029_20230309_20230320_02_T1_ST_B10.TIF # Level 2, band 10 (LST)
│ │ ├── LC08_L1TP_199029_20230309_20230320_02_T1_B10.TIF # Level 1, band 10 (infrared)
│ │ ├── ...
│ │ └── *.tif
│ ├── LC08_L2SP_199029_20230325_20230404_02_T1
│ │ └── *.tif
│ └── ...
├── tile199030
│ └── ...
└── ...
Note
Each sensor has a dedicated section in the configuration file, each containing three parameters:
keep_bands: selects which band(s)/product(s) to useenable_sensor_gapfilling: enables or disables temporal gapfilling (useful for thermal and IR images)temporal_resolution: sets the resolution for the gapfilling
Example:
chain:
{
...
}
Landsat8_usgs_thermal:
{
temporal_resolution = 16
keep_bands = ["B2", "B3", "B4", "B7"]
enable_sensor_gapfilling = True
}
Landsat8_usgs_thermal:
{
temporal_resolution = 16
keep_bands = ["B10", "EMIS"]
enable_sensor_gapfilling = False
}
Landsat8_usgs_infrared:
{
temporal_resolution = 16
enable_sensor_gapfilling = False
}...
Required images
In order to run using a landsat 8 sensor, the chain also requires at least 3 masks (included in downloadable products):
Cloud mask, called
QA_PIXEL(pixel quality assessment)Saturation mask, called
QA_RADSAT(radiometric saturation quality assessment)Metadata file, called
MTL
Usage with other sensors
It is also possible to use this (these) sensor(s) with other ones available in iota2 (i.e. Sentinel-2). Sentinel-2 and Landsat 8/9 data (provided by the USGS) use different tiling systems, so you first need to use a specific builder in order to re-tile one of the two datasets you are using. The process (for one tile) is the following:
Download landsat and sentinel images
Use iota2’s tiler builder (to the builder’s documentation for more details) with a first configuration file:
chain :
{
output_path : '/path/to/tiled/images'
first_step : 'tiler'
last_step : 'tiler'
proj : 'EPSG:2154'
rasters_grid_path : '/path/to/reference/images'
list_tile : 'T30TXQ'
features_path : '/path/to/images/to/be/tiled/'
spatial_resolution : 10 # mandatory but not used in this case. The output spatial resolution will be the one found in 'rasters_grid_path' directory.
}
builders:
{
builders_class_name : ["i2_features_to_grid"]
}
Place the images as expected by iota2. Images from different sensors don’t need to be in the same directory, but need to be in a directory with the same name, corresponding to the tile. For example:
├── landsat_data
│ └── T30TXQ # tile (common name for all sensors)
│ ├── LC08_L2SP_199029_20230309_20230320_02_T1 # date 1 directory
│ │ ├── LC08_L2SP_199029_20230309_20230320_02_T1_SR_B1.TIF
│ │ ├── LC08_L2SP_199029_20230309_20230320_02_T1_ST_B10.TIF
│ │ └── ...
│ ├── LC08_L2SP_199029_20230325_20230404_02_T1 # date 2 directory
│ │ └── *.tif
│ └── ...
└── sentinel_data
└── T30TXQ # tile (common name for all sensors)
├── SENTINEL2A_20230217-110844-292_L2A_T30TXQ_D_V3-1 # date 1 directory
│ ├── MASKS
│ │ └── SENTINEL2A_20230217-110844-292_L2A_T30TXQ_D_V3-1_*.tif
│ ├── SENTINEL2A_20230217-110844-292_L2A_T30TXQ_D_V3-1_FRE_B*.tif
│ ├── SENTINEL2A_20230217-110844-292_L2A_T30TXQ_D_V3-1_FRE_STACK.tif
│ └── ...
├── SENTINEL2B_20230304-110849-778_L2A_T30TXQ_D_V3-1
│ └── *.tif
└── ...
Run iota2 as usual, with two sensors. For example, in order to use thermal images from Landsat 8 and optical images from Sentinel-2:
chain :
{
output_path : '/path/to/output/'
remove_output_path : True
nomenclature_path : '/path/to/file'
list_tile : 'T30TXQ'
l8_usgs_thermal_path = '/path/to/landsat/images/'
s2_path : '/path/to/sentinel/images/'
ground_truth : '/path/to/file'
data_field : 'id'
spatial_resolution : 10
color_table : '/path/to/file'
proj : 'EPSG:32630'
first_step: "init"
last_step: "validation"
}
arg_train :
{
classifier : 'sharkrf'
otb_classifier_options : {"classifier.sharkrf.nbtrees" : 100 }
sample_selection: {"sampler": "random",
"strategy": "percent",
"strategy.percent.p": 0.1}
random_seed: 1234
}
arg_classification :
{
classif_mode : 'separate'
}
sensors_data_interpolation :
{
write_outputs: False
}