Creating GLT using ENVI
General steps for ENVI for orthorectification and georegistration for sample: 2015-02-01.190838.Cuprite.Line3-Run1-Segment01
- In ENVI open the Lat/Long data: 2015-02-01.190838.Cuprite.Line3-Run1-Segment01-110000-geo.dat - Note you must have the 2015-02-01.190838.Cuprite.Line3-Run1-Segment01-110000-geo.hdr file in the same folder, this tells ENVI the format of the file
- Create the GLT in ENVI following these general instructions. - Generally you can accept the default values in this step however you need to make sure that you select WGS-84 as the datum. When selecting the bands for the X and Y coordinates, use the notes from the geo metadata to guide you. One says "use for y" and one says "use for x".
- In ENVI, use the GLT created in the previous step to create a georeferenced image following these general instructions. - Again you can accept most of the default values. You'll just need to select what bands you want to use. For our L1 visuals we use band 150 (10.1 µm) for Red, band 100 (9.2 µm) for Green, and band 58 (8.5 µm) for blue. This step can take a while, especially with a large image.
In ENVI open the data you want to register: 2015-02-01.190838.Cuprite.Line3-Run1-Segment01-110000-level_1a.dat
- Again you need the associated .hdr file if this is a .dat file. Alternatively you could use the LST PNG, emissivity data, or similar visual here as long as it's the same width and height as the original image.
Once the processing on the last step is complete you'll have a georeferenced image in ENVI. ENVI also has a tool called something similar to "GLT and Georeference" (depending on the version of ENVI) that combines the GTL and georeference steps which you might find useful (since there's less clicking).