The last step of the Terascan processing is to export the volcanic cloud region
in ascii format using the Utilities/Export Ascii function of XVU. Select the
filename of the file made in select point listi,
and the variables to be exported (in this case latitude, longitude, avhrr_ch4 and avhrr_ch5). Furnish an output filename and make sure to select the
"no" option for list dims. Hit the run button, and wait a minute or two for the
data to be exported. Note that the cloud retrieval use a *.asc filter in the
program, so if you supplu a .asc suffix to the filename. the software will
be able to find it easier.
If your subsetted Terascan data file had "bad data points" (missing or no data),
these must be removed before the file is imported in the cloud retrieval
code. Bad data points are written out as 5 asterisks (*****), and can be
easily removed with the following unix sed command:
sed '/\*/d' filename> newfile
This command will deleat everyline that contains an asterisk in it. The
resulting data file is ready for use in the cloud retrieval.