Matching two flight lines by applying Boresight corrections

This page summarises how to match two flight lines together if they do not line up, by using boresight corrections.

---

Usage

The IDL script getboresight.pro will take 2 images and utilise either a feature match or area-based match to generate tie-points, or will use tie-points given in a separate file. When IDL is started, at the prompt type:

envi, /restore_base_save_files

This will setup the ENVI functionality. Then (if the getboresight.pro script is not in your current directory include the path to the file) type:

.compile getboresight.pro

to compile the script. To run the script type the following command, replacing the $words with their respective values:

getboresight, '$basefilename' ,'$warpfilename','$matchtype','$height','$HORIZONTAL','$headdir','$outputdirectory'

where

• $basefilename is the master/base file (tif image you want to match to)
• $warpfilename is the slave/warp file (tif you want to match to the basefile)
• $matchtype is either 'feature', 'area' or '<filename>' where filename is GCP file in ENVI format
• $height is the height of the aircraft when the warpimage was acquired
• $HORIZONTAL is either 'horiz' or 'nothoriz' depending on the heading of the aircraft. Suggest 'horiz' if heading is in ranges 355-005, 085-095, 175-185 or 265-275.
• $headdir depends on heading direction: '+' if heading 0->179 else '-'
• $outputdirectory is the name of a directory to spit out jpgs and txt files