TTools, airports.txt compile/decompile file changes

[Guest]

I am experiencing what seems like some kind of rounding errors from TTools. Try to follow me here.If I decompile traffic.bgl, and then right way compile it back from the files it just created without making any changes, and once again decompile it, the airports.txt file will have different values for the fix latitude and fix longitude the second time.For example, this is a line from my airports.txt after I just decompiled it from traffic.bgl for the first time.AYMD,S5* 11.93',E145* 46.64',10 This next line is the same airport after one compile/decompile cycle.AYMD,S5* 11.92',E145* 46.63',10Airports.txt or any other file was not touched in any way. I found out about this error after I received an error from Tcompiler about airports.txt. One of the airports fix longitude value had incresed or decreased (don't remember which) past the allowed range.Could someone else please test this and confirm that this is not just my system :)Why was I doing so many decompile/compile cycles in a row you may ask ? I am writing an Installation program for AI aircraft that is almost ready for beta. Anyone can create installation packages for it, and it will work alot better than Project AI's installer. You can for example reinstall same airliners with modified files, and not have double entries etc, delete installed airlines, and other neat stuff. I got the idea from tens of unofficial project AI files floating around, I got tired of adding them manually. With my installer, all you have to do is create a small config file, copy stuff into right directories and start the installer.

[tgibson 11]

Yes, TTols does have rounding errors, and you will compound them by repetitive compile and decompile cycles.Hope this helps,-- Tom GibsonCalifornia Classic Propliners: http://www.calclassic.com/Cal Classic Alco Page: http://www.calclassic.com/alco/Freeflight Design Shop: http://www.freeflightdesign.com/ San Diego Model RR Museum: http://www.sdmodelrailroadm.com/Drop by! ___x_x_(")_x_x___

[Guest 727Fan]

So Tom, what does this all mean, anyway? How does this fact alter the TTools operations?I'm asking because over the past 6 months, I've probably used the decompilecompile cycle at least 100 times. Are you suggesting to not use TTools anymore? I'm flying around the world, so before each flight I modify the flight plans and add aircraft for the next destination.And what's a "rounding error?" Does it effect the layout of an airport? How aircraft land at it? Thanks for clarifying!!Rick

[Guest]

What I learn to do many months ago was add all the airports to the airport.txt file and save it as a backup.Then after so many compiles I copy over my airport.txt file with an earlier version and re-compile. No compounding of rounding numbers.

[Guest Ideas]

The Rounding Error also shows up in the Times in Flightplans.txt

[tgibson 11]

A rounding error is due to the way computers store floating point numbers. There is a little error introduced each time that number is manipulated.The way to avoid it is to make backup files of things like your airport.txt file, as described by others. You'll have to continue to use TTools, since it is the only tool available to access the traffic.bgl file (all others also use TTools).Hope this helps,-- Tom GibsonCalifornia Classic Propliners: http://www.calclassic.com/Cal Classic Alco Page: http://www.calclassic.com/alco/Freeflight Design Shop: http://www.freeflightdesign.com/ San Diego Model RR Museum: http://www.sdmodelrailroadm.com/Drop by! ___x_x_(")_x_x___

[Guest 727Fan]

Tom. When you talked about floating pt units, does this mean the aircraft at airports will not be where they're supposed to be?I understand TTools rounding up or down the arrivaldeparture times in the flight plan txt. I can live with that.But the airport text thing bothers me. I don't use AFCAD as yet, but the time will come soon when I will be using it.After using TTools probably 200 times or more to edit the flight plans text, I'm wondering how the rounding error you talked about alters the sim. Can I start seeing visual changes to the sim?Are these errors fatal?And if I make a backup of the traffic bgl (which I do) are you saying I should insert the backup copy of the airport text periodically?Thanks again!!Rick

[Guest Joshieca]

Many moons ago I mentioned this to Lee and said that he would work on this for future updates to the program.The best way I know to combat this is as one user suggest was to keep a back file of your airport.txt, but also unless you need to you dont need to decompile the files after your recompile them.Let me explain....Lets say you add flightplans, either by hand or with a program such as AITM. Start with a file called "Basic_Flightplans.txt"When you add files or make changes with AITM, SAVE AS "flightplans.txt"Then when you compile you're compiling the changed flightplan file. As long as you dont decompile it, it wont alter the airport.txt file.[br][br][div align=center][br][link:members.cox.net/fstimes/wetimage.html]Click Here For Weather Image of the Day!

[Guest]

Gads, I wish I had seen your posts earlier, Tom. Would have saved me some time responding to the other gentleman who had the same problem. Your answers were much more succinct than mine!--Ron

[Guest Ideas]

I must be living Right, the only times I am getting the errors is when I use a "Front End" to TTools. If I use a "Front End" I get the errors every time.