162 lines
4.6 KiB
Markdown
162 lines
4.6 KiB
Markdown
# Processing NetCDF file
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Other than ENVI and HDF5, NetCDF support is added for reading and writing. Meanwhile, Geographic Lookup Table (GLT) of raster image can be used to reproject input image.
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Configuration json file is slightly different from the basic configuration (an example for topo correction: [nc_topo_correct_config.json](../examples/configs/nc_topo_correct_config.json)).
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## Topograhic Correction
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NetCDF and its OBS files can be accessed to implement the basic normalization like topographic correction. Configuration file can be setup like below. anc_files can be either nc format or envi format.
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```json
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"anc_files": {
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"/data/EMIT/EMIT_L2A_RFL_001_20231101T024133_2330502_014.nc": {
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"path_length": [
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"/data/EMIT/EMIT_L1B_OBS_001_20231101T024133_2330502_014.nc",
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0
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],
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"sensor_az": [
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"/data/EMIT/EMIT_L1B_OBS_001_20231101T024133_2330502_014.nc",
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1
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],
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"sensor_zn": [
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"/data/EMIT/EMIT_L1B_OBS_001_20231101T024133_2330502_014.nc",
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2
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],
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"solar_az": [
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"/data/EMIT/EMIT_L1B_OBS_001_20231101T024133_2330502_014.nc",
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3
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],
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"solar_zn": [
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"/data/EMIT/EMIT_L1B_OBS_001_20231101T024133_2330502_014.nc",
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4
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],
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"phase": [
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"/data/EMIT/EMIT_L1B_OBS_001_20231101T024133_2330502_014.nc",
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5
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],
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"slope": [
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"/data/EMIT/EMIT_L1B_OBS_001_20231101T024133_2330502_014_nc_warp_v1.bsq",
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0
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],
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"aspect": [
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"/data/EMIT/EMIT_L1B_OBS_001_20231101T024133_2330502_014_nc_warp_v1.bsq",
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1
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],
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"cosine_i": [
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"/data/EMIT/EMIT_L1B_OBS_001_20231101T024133_2330502_014_nc_warp_v1.bsq",
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2
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],
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"utc_time": [
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"/data/EMIT/EMIT_L1B_OBS_001_20231101T024133_2330502_014.nc",
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9
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]
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}
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},
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```
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There is a sample image correct script for nc files and GLT ( [image_correct_export_nc.py](../scripts/image_correct_export_nc.py)).
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```bash
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python ./scripts/image_correct_with_glt.py path/to/the/configuration/json/file
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```
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Before and after topo correction
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## External GLT
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Many NetCDF files have internal GLT, but sometime a geo-rectification is needed, and a new corrected GLT can be used for warping the pixels to new geographic positions.
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If internal GLT is used, set a blank glt file path
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```json
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... ...
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},
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"glt_files": { },
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"export": {
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... ...
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```
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External GLT can be specified in the configuration file, it should have at least two bands: GLT_X and GLT_Y
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```json
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... ...
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},
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"glt_files": {
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"/data/EMIT/EMIT_L2A_RFL_001_20231101T024133_2330502_014.nc": {
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"glt_x": ["/data/EMIT/EMIT_L2A_RFL_001_20231101T024133_2330502_014_glt.bsq",1],
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"glt_y": ["/data/EMIT/EMIT_L2A_RFL_001_20231101T024133_2330502_014_glt.bsq",0]
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}
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},
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"export": {
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... ...
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```
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To use GLT to warp image or not is controlled by ```use_glt``` in ```export```.
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```json
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"export": {
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...
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"image": true,
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"use_glt":true,
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...
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},
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```
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Export without using GLT
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Export warped image with GLT
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To export NetCDF image or not is controlled by ```image_format``` in ```export```. ```"envi"``` is the default output format, if ```image_format``` is not set. If ```"netcdf"``` is selected, information from ```"outside_metadata"``` will be written in the output. Information can either be in a dictionary in the config file or a json file.
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```json
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"export": {
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...
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"image_format": "netcdf",
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...
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},
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...
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"outside_metadata":{ "XXX":"XXXXX", ... },
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...
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```
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Alternatively, it can be
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```json
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"export": {
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...
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"image_format": "netcdf",
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...
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},
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...
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"outside_metadata":"XXX/XXXX.json",
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...
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```
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## Trait Prediction
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Output format of trait prediction image file can also be ```"netcdf"```, which is ```"envi"``` by default.
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There is a sample trait export script for nc files and GLT ( [trait_estimate_nc.py](../scripts/trait_estimate_nc.py)).
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Accordingly, several items in the trait configuration file has to be set for this purpose.
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```json
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{
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"file_type": "ncav",
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"export_type":"netcdf",
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"use_glt":false,
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"output_dir": "...",
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"outside_metadata": "...",
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...
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}
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``` |