Now that the data file has been registerd, and the volcanic cloud identified, the data values can be subset for use in the volcanic cloud retrieval. The first step is to select the general region of the volcanic cloud. This is done using the Select/Locations function. If you choose this, a window like the one on the right appears. Select an output filename, whether you want the region to be a box or an outline, and make sure that the lat/lon coordinates are select on the bottom. First click "run" button
To define a box, click with the left mouse button, and drag the window over the desired region, hit the middle button to anchor the window, and then the right button to write the file.
To define an outline, click around the perimeter with the left button, close the polygon with the middle button, and hit the right button to write the file.
Now that the location is selected, subset the point in that region using the Select/Point List function of xvu. Select the filename (registered TDF file), variables to be output (in this case, latitude, longitude, achrr_ch4 and avhrr_ch5) and the name of the point file (box or outline file). Specify the output filename, and whether the point file is an outline or a box. Finally, answer yes to the save coords question. Once this is done, the data file is ready to be exported out of Terascan and into the volcanic cloud retrieval.
This page maintained by Dave Schneider (email@example.com)