Occultation Path Lines on Microsoft Streets and Trips Format Maps
General Method for Creating Asteroidal Occultation Path Lines on Microsoft Streets and Trips Format Maps
(Second draft 7-21-2005 by Tony George)
Special thanks to Geoff Hitchcox (Kiwi Geoff) for spearheading this project for IOTA, developing SHADOW.EXE and for giving me all the information needed to make this process work.
Download Kiwi Geoff's SHADOW program and associated files to your computer root drive. [you must use a root drive as the DOS program st2gpx does not recognize Windows expanded file structure]
This program must also be accompanied by file named 'path.txt'. See below.
Download the st2gpx program and it's associated files to the computers root drive.
This is a DOS program. It is not user friendly. You have to run it from a properly formatted Windows RUN prompt from a DOS batch file using the Windows RUN prompt. More on this below.
Once these programs are downloaded, use the following instructions to create the path.txt file, then the track.gpx file and finally the asteroid.ext file as follows:
1. Use the internet to access Steve Preston's asteroid occultation prediction files.
2. Choose (click on) an asteroid event you are interested in.
3. This will bring up the webpage with several links and maps on it. Find the link named 'Detailed Info' and click on it.
4. This will bring up a HTML text image of the data file for the predicted occultation event. Save this file as 'Path.txt' in the computer root directory. Another method is to right click on the 'Detailed Info' link and 'Save Target As'�and then save as Path.txt in the previously selected root directory
5. Run SHADOW.EXE - this will automatically create several files, one called TRACK.GPX is the output file that you will use in st2gpx below (unless you want dots instead of lines in which case you will use the file POINTS.GPX).
6. Next, create a Microsoft Street and Trips 'template' map file for the software to "add" the track data to. You only need to do this once. [A template map is basically an empty map for your version of Streets & Trips which has been formatted for pushpins. st2gpx can't import data into a map file unless it is formatted for pushpins.] Here is how you would do it. You start with a new map (file\new) in Streets & Trips. Create a single pushpin, then delete the pushpin (this formats the map structure for pushpins). Then save this file with a name like "occult.est".]
7. Once you have the template file you can use "st2gpx" to add the GPX data to it. Open the Windows RUN prompt (Press START and then RUN). In the RUN window type:
C[or E or F or whatever root directory letter you are using]:/st2gpx.exe -g track.gpx -F asteroid.est occult.est
-g indicates the file is a gpx format fiile. TRACK.GPX is the file that was created by SHADOW.EXE (or you could use POINTS.GPX is you wanted points on the map instead of lines).
-F indicates you are going to output thee track data in a modified Streets and Trips file using the "occult.est" file as the model file and the 'asteroid.est' as the output file. Instead of 'asteroid' you can insert the name of the occulting asteroid or any other file name you would like to use, but keep it at 8 characters since we are in DOS.
[If you would prefer to run a .BAT file instead of using the Microsoft RUN menu box, then follow the recipe for the GO.BAT file at the end of this file and just RUN that instead.]
8. Now, you should be able to open the 'asteroid.est' file you just created using Microsoft Street and Trips and see the asteroid path, including the centerline, northern and southern limits, and the northern and southern 1 sigma limits. The lines are in the same color as the pushpin you created in the occult.est file. You can change the color, but all the lines change at the same time.
If you don't like the lines, but instead would like a dot at each of the predicted line coordinate locations, then substitute the file 'POINTS.GPX' for the file 'TRACK.GPX' and you will only get lines of dots on your Microsoft Streets and Trips maps. You can then link those dots with lines if you wish and do any shading between the lines you prefer.
If you don't like to retype the run command each time, you can use the following BAT file to run all the above programs and commands:
(special thanks again to Kiwi Geoff for this routine):
rem ------------------ GO.BAT ----------------------------------
rem Call this batch file with Asteroid name e.g GO camelia
rem File creation for Asteroid %1
rem will return a file named camelia.est for processing in
rem Microsoft Streets and Trips
shadow
st2gpx.exe -g track.gpx -F %1.est occult.est
exit
rem ------------------------------------------------------------
Have fun!
Questions or comments on this process. Contact me
Tony George.