Georeferencing EMIT L2B Mineral Maps

The emit_tools Pyton workflow currently doesn't support georeferencing EMIT L2B mineral maps, so here is a workaround:

1. Open a terminal/PowerShell and activate a conda environment with GDAL

2. Extract all the layers from the NetCDF file using the following command, replacing input and output file names with your data:

gdal_translate -of ENVI -sds /Users/dan.sousa/Downloads/EMIT_L2B_MIN_001_20230601T202647_2315214_005.nc /Users/dan.sousa/Downloads/EMIT_L2B_MIN_001_20230601T202647_2315214_005_e

3. This should create 9 files (1 for each subdataset in the NetCDF file). Their meaning is as follows:

  SUBDATASET_1_NAME=group_1_band_depth

  SUBDATASET_2_NAME=group_1_mineral_id

  SUBDATASET_3_NAME=group_2_band_depth

  SUBDATASET_4_NAME=group_2_mineral_id

  SUBDATASET_5_NAME=location/lon

  SUBDATASET_6_NAME=location/lat

  SUBDATASET_7_NAME=location/elev

  SUBDATASET_8_NAME=location/glt_x

  SUBDATASET_9_NAME=location/glt_y

4. In ENVI Classic, go to: Map > Georeference from Input Geometry > Build GLT

5. For "Input X Geometry Band", select File 5 that you created in the previous step (lon)

6. For "Input Y Geometry Band", select File 6 that you created in the previous step (lat)

7. Make sure that the "Input Projection of Geometry Bands" is set to "Geographic Lat/Lon", "WGS-84", "Degrees" 

8. Make sure that the "Output Projection for Georeferencing is what you'd like it to be (usually a UTM projection)

9. Click OK

10. Make sure pixel size is about right (usually about 63 meters, if using UTM)

11. Enter output filename for GLT file (append _GLT)

12. Click OK and allow to run

13. In ENVI Classic, open bands 1 through 4 of your dataset

14. Save these 4 bands as an ENVI meta file (File > Save File As > ENVI Meta > Import bands > remember to reorder them correctly > save with sensible filename)

15. In ENVI Classic, go to: Map > Georeference from Input Geometry > Georeference from GLT

16. Select the GLT file (that you just created) and click OK

17. Select the ENVI meta file with the first 4 bands (that you just created), and click OK

18. Enter output filename for orthorectified mineral map (append _MinGeo)

19. Geolocation complete.