I just downloaded the ASTER LT1 HDF file. How do I convert it to Geotiff using ENVI. Or do you know any conversion tools that are accessible to use for free. Previously, when I downloaded ASTER data from GloVis there was an option that allowed me to choose either HDF or Geotiff format, but apparently the system has changed and it automatically downloads ASTER data as HDF file.
-HDF ASTER files can be imported into ENVI using Open->EOS->ASTER. Then you can convert bands to Geotiff using the Save As -> (ENVI,TIF,NITF,DTED) command.
-You can still download Geotiff files for ASTER L1T images using USGS Earth Explorer instead of GloVis. Standard product option is HDF file (as its a stack of different multiple band rasters), but Visible and Thermal Products options gets you the Geotiff files. Possibly the same could apply to GloVis available options for download, but I've stopped using it after the rennovation as it became less practical to use and doesnt work most of the times. I suggest using Earth Explorer or NASA Earthdata instead (both offer ASTER L1T access).
-QGIS has the very useful Semi-Automatic Classification Plugin (SCP), which has the capability to search, download and convert (to geotiff) ASTER, Landsat, Sentinel-2, Sentinel-3 and MODIS images. It also offers some extra options in conversion, like temperature and simple atmospheric correction.