Turnpoint list creation checklist

On Thursday, November 20, 2014 4:42:51 PM UTC-5, 2KA wrote:
(This reply is specific to the USA)

Chris,

Your list shows that you have put a lot of good thought into the topic. However, I've been creating turnpoint lists for contests and other uses for some years, and my process looks quite different. There are a couple of reasons for this:

- There are automated tools to do many of the things you mention, such as generating names, renumbering, composing airport lists, and so forth.

- The problem of keeping the airport data current is actually much more difficult than you might think. Most of the tunrpoint lists I see are materially stale. This happens because airports (especially private ones) close, frequencies and ID's change, and so forth. These kinds of changes are actually more frequent than many people realize.

So here is my process:

1. Concentrate on getting the control points established first, primarily using tasking considerations. These are the ones that would be numbered points in a contest, including the starts and finishes. Produce a list that contains ONLY the control points. Many people like to use SeeYou for this planning, and produce a .CUP file at the end.

2. Add to this list any unofficial airports or outlanding places you might want to include. These are the ones that would not appear in official databases. Designate these as "Outlanding Place" in SeeYou. This plus the control points from step #1 become your master list.

3. Compose a "black list" of airports that you want to exclude from your final database. These are ones that appear in the official sources, but for some reason should not be included. Perhaps the airport doesn't actually exist, or there is some reason you really wouldn't want to land there.

4. Use an automated tool such as my website (http://www.soaringdata.info) to fill the turnpoint list with airports. There are a couple of ways of doing this. One is to select a centerpoint and a radius. Another is to let the system to compute a bounding polygon for the turnpoints, and include all the airports within or near the boundaries. My system will produce a Soaring Turnpoint Exchange (STX) format file as well as CUP and a few other output formats. It will also automatically produce companion special use airspace files for the area covered by the turnpoints.

5. Make any hand edits you think necessary. You can choose to correct mistakes that might originate in official data here. There is also a way to make error reports to the FAA so that the official data gets fixed.

6. Submit the STX file to the Soaring Turnpoint Exchange. John Liebacher has automated tools to automatically translate it to literally dozens of different formats, complying with name and other restrictions unique to each.

7. When it comes time to update the database, you just start at step #4. You get fresh airport and airspace data painlessly.

I can provide detailed help with any of these steps if you would like to contact me separately. You can use the "Questions and Comments" link on my site.

Best of Luck

Lynn Alley
"2KA"

Lynn,
Thanks for the reply. In all practicality how often do you think we should update the official turnpoint lists for clubs and contest sites?

It is fair amount of work for the person doing it, as well as other volunteers [John L], but also pilots do seem absolutely resistant to going out and getting updated turnpoint files often. If I updated the local turnpoints list annually or even every 2-3 years I suspect I would get nastygrams from pilots. Nobody wants to find out they have the wrong TP file after they launch or get scored. Pilots don't seem to be in the habit of getting the latest data often.

Chris

For contest sites I definitely think they should be updated for each contest held or at least annually. If you follow the procedure I outlined above, it takes little time to update airport and airspace data -- certainly less than an hour. It makes John's life a little simpler also to have the input in an STX file. His tools handle things pretty automatically.

I update the local database (radius about 350 miles) in my glider a couple of times a year. There are material differences every time I do it. After frequency changes, the most common, unfortunately, is airport closures. New ones do open up from time-to-time.

Note also that simply updating airport information does not affect names, numbers, or locations of control points.

On Thursday, November 20, 2014 11:05:10 AM UTC-5, Dan Marotta wrote:
A very good process!* I would only
object to the notion of "bias" towards the official data.*

Wrong is wrong, no matter who publishes the information.* If you
know that the official data is incorrect, publish the correct data
for glider use and notify the publisher of his mistake.* Maybe
he'll even correct it.
Dan Marotta

I agree in theory wrong is wrong but in all practical purposes how wrong does it have to be to matter? 0°00.001 ? .1 mile, .5miles?
I chose about 750 foot as some kind of standard for positional placement, I'm completely open to feedback on this. I've tried to navigate to data points dislocated from the airports by 1 add 2 miles and really struggled to find it [not fun when you are low]. But it was within about .3 miles [1500ft] I could usually spot it.

One concern is even though all the turnpoint files say "unofficial- use at your own risk" there does seem to be a preference to leave the responsibility with the FAA instead of modification for minimal gain in accuracy. Also each time you change it, Liebacher's program is going to try to "snap it back" to official data so that is just more work for everyone.

Chris

Thanks for the reply.

Dan Marotta

On 11/21/2014 10:43 AM, wrote:
On Thursday, November 20, 2014 11:05:10 AM UTC-5, Dan Marotta wrote:
A very good process! I would only
object to the notion of "bias" towards the official data.

Wrong is wrong, no matter who publishes the information. If you
know that the official data is incorrect, publish the correct data
for glider use and notify the publisher of his mistake. Maybe
he'll even correct it.
Dan Marotta
I agree in theory wrong is wrong but in all practical purposes how wrong does it have to be to matter? 0°00.001 ? .1 mile, .5miles?
I chose about 750 foot as some kind of standard for positional placement, I'm completely open to feedback on this. I've tried to navigate to data points dislocated from the airports by 1 add 2 miles and really struggled to find it [not fun when you are low]. But it was within about .3 miles [1500ft] I could usually spot it.

One concern is even though all the turnpoint files say "unofficial- use at your own risk" there does seem to be a preference to leave the responsibility with the FAA instead of modification for minimal gain in accuracy. Also each time you change it, Liebacher's program is going to try to "snap it back" to official data so that is just more work for everyone.

Chris

On Fri, 21 Nov 2014 18:02:02 +0000, Tim Newport-Peace wrote:

For UK, the BGA Waypoint List is re-published annually. Principally
because Pilots request additions, but also due to changing airspace
considerations. But not more frequently, unless there is a major issue,
such as safety considerations.

I think there's a major difference between the BGA list and 2KA's one:
2KA is including a lot of landout fields that aren't turnpoints, while
AFAICT the only landable waypoints in the BGA list are turnpoints that
are either on or close to an airfield with a resident gliding club.


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |

When making a new turn-point list I try to pick 'landable' points whenever possible. Mark them AL for airports and L for known good landing areas. Points should be 15 to 20 miles apart. Mountain tops should never be used (pick coordinates down the mountain side and away from the top, a mile or so). Add a couple of close in turns for finishing a MAT,,,,,,say 5 miles one direction and 10 miles the opposite direction. With GPS scoring, exact coordinates are no longer necessary because the pilot is required to get within 1 mile of the coordinates you specify. Keep names understandable using 7 characters ( several computer systems only allow 7 characters )
JJ

On Sunday, November 23, 2014 10:18:07 PM UTC-5, JJ Sinclair wrote:
When making a new turn-point list I try to pick 'landable' points whenever possible. Mark them AL for airports and L for known good landing areas. Points should be 15 to 20 miles apart. Mountain tops should never be used (pick coordinates down the mountain side and away from the top, a mile or so). Add a couple of close in turns for finishing a MAT,,,,,,say 5 miles one direction and 10 miles the opposite direction. With GPS scoring, exact coordinates are no longer necessary because the pilot is required to get within 1 mile of the coordinates you specify. Keep names understandable using 7 characters ( several computer systems only allow 7 characters )
JJ

JJ, can you clarify why Mountain tops should never be uses? Is this because you have to be at least as high as the point to round the turnpoint? This could be bad if the peak is higher than the top of the lift.
Chris

On Sunday, November 23, 2014 10:18:07 PM UTC-5, JJ Sinclair wrote:
When making a new turn-point list I try to pick 'landable' points whenever possible. Mark them AL for airports and L for known good landing areas. Points should be 15 to 20 miles apart. Mountain tops should never be used (pick coordinates down the mountain side and away from the top, a mile or so). Add a couple of close in turns for finishing a MAT,,,,,,say 5 miles one direction and 10 miles the opposite direction. With GPS scoring, exact coordinates are no longer necessary because the pilot is required to get within 1 mile of the coordinates you specify. Keep names understandable using 7 characters ( several computer systems only allow 7 characters )
JJ

JJ, can you clarify why Mountain tops should never be used? Is this because you have to be at least as high as the point to round the turnpoint? This could be bad if the peak is higher than the top of the lift.
Chris

On Monday, November 24, 2014 9:43:57 AM UTC-5, wrote:
On Sunday, November 23, 2014 10:18:07 PM UTC-5, JJ Sinclair wrote:
When making a new turn-point list I try to pick 'landable' points whenever possible. Mark them AL for airports and L for known good landing areas. Points should be 15 to 20 miles apart. Mountain tops should never be used (pick coordinates down the mountain side and away from the top, a mile or so). Add a couple of close in turns for finishing a MAT,,,,,,say 5 miles one direction and 10 miles the opposite direction. With GPS scoring, exact coordinates are no longer necessary because the pilot is required to get within 1 mile of the coordinates you specify. Keep names understandable using 7 characters ( several computer systems only allow 7 characters )
JJ

JJ, can you clarify why Mountain tops should never be used? Is this because you have to be at least as high as the point to round the turnpoint? This could be bad if the peak is higher than the top of the lift.
Chris

Some years ago I oo'd a 100 km O&R record try in Colorado wave (Silver West - 143 kph average - in a 1-26!) but the TP was in the clouds and far enough in them that no part of the sector was available (speed meant diving under the clouds was out). I now put TPs offset from the hills, to avoid this. Peaks were good when turnpoint photography was in.

Mountain top turnpoints have the potential to make the pilot choose between safety and completion of the task. I remember one mountain top TP located deep in the mountains, I couldn't get high enough to nick the 1 mile circle because rocks and trees were in the way. After trying for 20 minutes or more, I found myself too low to fly out............I was trapped! 'Fly-or die! After 30 minutes of intense concentration of sun/wind/terrain I was able to escape. Why was I there? Because I let points overpower safety, but this situation could have been prevented by the guy that made up the data base..
JJ