I have recently downloaded some data from the official SpecTIR website for some personal research interests. The website says that the ZIP file contains information about how to geo-reference the image sets. Appropriate information is given in the webpage and the links to download the data as well. I downloaded the Gulf of Mexico Wetland Sample (Lower Suwannee NWR) dataset, which are in ENVI Header file format.

Can anyone provide any insight into this? Else, can anyone at least point to the right forum, in case this is not appropriate for GIS-SE.


Found an answer myself... It so happens that SpecTIR releases these GLT (Geographic Lookup Table) and IGM (Input Geometry) files along with the Radiance image file for georeferencing, as a georeferenced image is much heavier than the available 100-150 MB files on the website.

The datasets are fantastic, for freely available information.

Georeferencing can be done using either the GLT or the IGM file depending on the application you are using. However, ENVI supports the use of both files...

Detailed methodologies for using the GLT and IGM files is given here (link) (also illustrated is how to 'build' these GLT files), and descriptions with a HyMap dataset is described here (pdf).

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