The following instructions describe how to open ASTER data using the ENVI 5.x Standard interface. You can perform the same steps in ENVI Classic under the Basic Tools menu. ASTER data sets and products are distributed in the hierarchical data format (HDF). Use the following method to properly open and calibrate these data in ENVI.
- In ENVI 5.3, from the ENVI menu select File | Open As | Optical Sensors | EOS | ASTER.
- In prior versions of ENVI 5.x, from the ENVI menu select File | Open As | EOS | ASTER.
ASTER scenes contain files with three different spatial resolutions. When you open the HDF file the ENVI software creates up to four virtual files for these data. The first contains three VNIR bands with 15m resolution. The second, for L1B data only, is the backward viewing NIR band, also at 15m resolution and rarely used. The next file contains six SWIR bands at 30m resolution. Note that images acquired after April 2008 do not have the SWIR data. Finally the last file contains the five TIR bands at 90m resolution.
In most cases ASTER products have been scaled before archiving at the USGS. Please read the USGS product documentation to determine if these data must be rescaled, and what is the appropriate value.
ASTER L1B data and ASTER products (as of this writing) are delivered in along track orientation and should be rotated to north-up orientation. This is described in the Image Rotation FAQ on this site.