Re: [Flightgear-devel] International Runway Issue (leading zeros)
John Denker wrote: If anybody is interested, I can provide a file apt-state.dat that non-heuristically specifies which airports are in the US -- and even specifies which state. This would lower the error rate rather dramatically. I think we're talking about a 'problem' which is seeking for a soution that works for more than just one single country. Cheers, Martin. -- Unix _IS_ user friendly - it's just selective about who its friends are ! -- -- Let Crystal Reports handle the reporting - Free Crystal Reports 2008 30-Day trial. Simplify your report design, integration and deployment - and focus on what you do best, core application coding. Discover what's new with Crystal Reports now. http://p.sf.net/sfu/bobj-july ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] International Runway Issue (leading zeros)
On 11/15/2009 04:11 AM, Martin Spott wrote: John Denker wrote: If anybody is interested, I can provide a file apt-state.dat that non-heuristically specifies which airports are in the US -- and even specifies which state. This would lower the error rate rather dramatically. I think we're talking about a 'problem' which is seeking for a soution that works for more than just one single country. Perhaps you could explain why you think the proposed solution does not work with very high accuracy worldwide. In particular, if you know of any non-US airports that don't use leading zeros, beyond the handful already accounted for, please explain. -- Let Crystal Reports handle the reporting - Free Crystal Reports 2008 30-Day trial. Simplify your report design, integration and deployment - and focus on what you do best, core application coding. Discover what's new with Crystal Reports now. http://p.sf.net/sfu/bobj-july ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] International Runway Issue (leading zeros)
On Sun, Nov 15, 2009 at 12:28 AM, John Denker j...@av8n.com wrote: On 11/14/2009 11:36 AM, Curtis Olson wrote: I suppose we could use some heuristic such as: 4 character airport code that do not start with K or P use a leading zero, and all other airports omit the leading zero? We could setup the code logic to be extensible if we find other countries that also tend to omit the leading zero. That doesn't give us individual control over individual runways, but it might make things generally better than they are now? I missed something in my original email I see. In addition, any airport codes that are 3 characters long would be assigned to the USA. I think we use 4 character ICAO codes for everything outside the USA. On the other hand, this assumes that the USA is the only country that doesn't use leading zeros on the runways which I doubt is the case. Curt. -- Curtis Olson: http://baron.flightgear.org/~curt/ -- Let Crystal Reports handle the reporting - Free Crystal Reports 2008 30-Day trial. Simplify your report design, integration and deployment - and focus on what you do best, core application coding. Discover what's new with Crystal Reports now. http://p.sf.net/sfu/bobj-july___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] International Runway Issue (leading zeros)
On 11/15/2009 06:08 AM, Curtis Olson wrote: On Sun, Nov 15, 2009 at 12:28 AM, John Denker j...@av8n.com wrote: On 11/14/2009 11:36 AM, Curtis Olson wrote: I suppose we could use some heuristic such as: 4 character airport code that do not start with K or P use a leading zero, and all other airports omit the leading zero? We could setup the code logic to be extensible if we find other countries that also tend to omit the leading zero. That doesn't give us individual control over individual runways, but it might make things generally better than they are now? I missed something in my original email I see. In addition, any airport codes that are 3 characters long would be assigned to the USA. For me at least, that was sufficiently implied by the original email. That's why I explicitly referred to the K... P... ... heuristic. The last part (the three dots alone) was meant to match three-letter IDs. I think we use 4 character ICAO codes for everything outside the USA. Mostly but not entirely true. There are about 250 three-letter airport IDs outside the US. On the other hand, this assumes that the USA is the only country that doesn't use leading zeros on the runways which I doubt is the case. It is easy to handle any such countries. Anybody who knows of any is encouraged to report them. There can't be very many. -- Let Crystal Reports handle the reporting - Free Crystal Reports 2008 30-Day trial. Simplify your report design, integration and deployment - and focus on what you do best, core application coding. Discover what's new with Crystal Reports now. http://p.sf.net/sfu/bobj-july ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] International Runway Issue (leading zeros)
Given the number of airfields in the US I think this is a good idea as long as we can implement it without breaking genapts, I'm going to go forward with heuristically-defining other runway markings since there shouldn't be any problems with defining single-wide markings for some European countries. Cheers John -- Let Crystal Reports handle the reporting - Free Crystal Reports 2008 30-Day trial. Simplify your report design, integration and deployment - and focus on what you do best, core application coding. Discover what's new with Crystal Reports now. http://p.sf.net/sfu/bobj-july ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
[Flightgear-devel] International Runway Issue (leading zeros)
On 11/14/2009 11:36 AM, Curtis Olson wrote: I suppose we could use some heuristic such as: 4 character airport code that do not start with K or P use a leading zero, and all other airports omit the leading zero? We could setup the code logic to be extensible if we find other countries that also tend to omit the leading zero. That doesn't give us individual control over individual runways, but it might make things generally better than they are now? That's the right question. Let's see if we can quantify the answer. If we always omit the leading zero, we will be wrong 37% of the time, approximately. This is the current behavior. If we always use the leading zero, we will be wrong the other 63% of the time, approximately. If we use the K... P... ... heuristic, that improves things about 29%, so we will be wrong only about 35% of the time, approximately. That is to say, there are quite a few US airports that are wrongly missed by the K... P... ... heuristic, and a few non-US airports that are wrongly caught. So this would be only a rather marginal improvement. If anybody is interested, I can provide a file apt-state.dat that non-heuristically specifies which airports are in the US -- and even specifies which state. This would lower the error rate rather dramatically. By way of further improvement, observe that Air Force bases within the US generally use leading zeros. Google Luke AFB or Dover AFB or Andrews AFB if you want to see some examples. We can check the airport name (in apt.dat) and see if it says AFB. Alas, it appears that some Navy facilities use leading zeros (Miramar) while others don't (Lakehurst). Eliminating this source of error will take an hour or two of hand-work. Finally, there are a handful of airfields in the Pacific that drop the leading zeros. We can pick these up with the P... heuristic. There may be some other check(s) that might be worth making, but none that I can think of right now. Bottom line: It should be easy and straightforward to reduce the rate of leading-zero errors to negligible levels, i.e. to some rate very small compared to the rate of plain old errors in the database. This is definitely worth doing. Having the wrong markings on a runway looks mighty peculiar, even if it is something with no real significance, such as a leading zero. -- Let Crystal Reports handle the reporting - Free Crystal Reports 2008 30-Day trial. Simplify your report design, integration and deployment - and focus on what you do best, core application coding. Discover what's new with Crystal Reports now. http://p.sf.net/sfu/bobj-july ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
