====== Blank geo...unw Output File ====== This most frequently occurs when ROI_PAC starts unwrapping the image in a decorrelated area. To correct this problem, edit the ''param.txt'' file giving a good seed point to start the unwrapping: - Use mdx.pl to open the file ''phase_var_ODR_4rlks.msk'' from the ''INT'' directory - View the phase image channel by clicking RMG_Hgt button. You may need to change the color scale mode in the RMG-Hgt Parameters box in order to see the correlated areas if the image is very decorrelated. (On a Mac this box is accessed by holding the Apple key and clicking the RMG-Hgt button.) - Clicking a point in the image will display the X and Y coordinates at the top left of the display, followed by the amplitude value, and finally the correlation value. Choose a point that has a high correlation (at least 0.7, 0.9 is better) within a generally well-correlated region and note the coordinates. - Add the following lines to the ''param.txt'' file, substituting the coordinates of the chosen point:\\ ''unw_seedx=//(x coordinate)//'' \\ ''unw_seedy=//(y coordinate)//'' - Delete any ''*.flg'' files in the ''INT'' directory - Run ''process_2pass'' starting at 'filtered':\\ ''$ process_2pass.pl param.txt filtered done'' - New output files will be created.