Category: Nav Data

Design and construction of a navigation data community to replace and supplement the DAFIF data.

No, that’s not good either

I wrote about some work I’ve been doing on the Waypoint Generator in Rants and Revelations » Getting there, still some collateral damage. In that, I said I wanted to do some more testing. Well, I did. I reloaded the entire DAFIF dataset. The test took 4 straight days to run, and that’s not including losing a day or so when my router lost its mind. And what this test told me is that the new algorithm for eliminating duplicate points is overzealous.
For instance, it classified two Canadian airports, CYEE Midland/Huronia and CNL8 Wyevale/Boker Field, as being the same. They’re actually nearly two nautical miles apart.

I was calling points the same if the types matched and they’re within 0.05 degrees latitude and 0.05 degrees longitude of each other. Unfortunately that is just about 3 nautical miles in the north/south direction, which this test has shown is too wide a net.

The problem is that I want to spot duplicates when a waypoint changes id, AND when they update the coordinates. I’ve seen places where they’ve updated the coordinates by half a degree, especially in the case of user-entered data.

I think what I’m going to have to do is trust that the coordinates aren’t going to change a whole bunch at the same time the id changes. So what I’ll do is call something a duplicate if it’s within 0.05 degrees if the ids match, but within 0.01 degrees if the ids don’t match. That’s less than a nautical mile, and it would be pretty odd to find two airports within a nautical mile of each other. (A lot less odd to find heliports or reporting points, unfortunately.)

Damn, this means another multi-day test run, unfortunately.

Jeppesen Responds

After receiving the email I mentioned in Rants and Revelations » Who’d have thunk it?, I responded with

I have renamed the part of the Wiki that uses the trademarked word
“NavData” to “DAFIFReplacment”. However, I am going to continue to use
the “/navdata/” part of the URL as that is a generic term and
untrademarkable and changing would break people’s bookmarks. You can
have a look at http://xcski.com/navdata/ if you wish.

I hope that meets your requirements.

Evidently their lawyers work nights, or they’ve outsourced it to India or something, because I got a response at 8:47pm:

Mr. Tomblin,

We appreciate your prompt action and reply to our notice.

While we cannot agree that the navdata term is generic, we understand the
bookmark issue and are satisfied with your action regarding this matter.

John Jaugilas
Jeppesen Intellectual Property
(303) 328-4178

Who’d have thunk it?

Well, it turns out that using the WikiWord “NavData” has upset Jeppesen Sanderson because they’ve got a product with that name, and they’ve sent me an email telling me to stop using the word or they’ll start legal action. I’m still using the word “navdata” because lots of people use it as a generic word meaning “navigation data”. So my Wiki url is still http://xcski.com/navdata/, but all deep links you might have are broken. Replace the word “NavData” with “DAFIFReplacement”.

Morning Rant #2: Spam Frustrations

I have a Wiki that I set up to try to stimulate some discussion about some sort of replacement to the DAFIF data that is going away in October. So far, it’s been pretty much a bust – nobody has contributed anything in months, nobody has done any of the grunt work like figuring out a database schema or XML schema or even the user interface, and so I’m thinking of forgetting the whole idea. I don’t have the time to do all the work myself, and if nobody else is going to do any, it isn’t going to get done. But that’s not what this rant is about.

This morning, I get a notification from the Wiki software that somebody has edited nearly every single page in the whole damn Wiki. Needless to say, it was all spam. It took me nearly two hours of messing around in RCS to get rid of every instance of the spam. But even worse, is that it turns out that somebody had already inserted the same spam into the navigation bars of the wiki months ago, and I hadn’t noticed. So my Wiki is actually showing up quite high in Google searches for certain drugs. ARGGGH!

Also, a while ago I mentioned that this blog tends to get spam in brief spurts of a few dozen spams over the course of a weekend, and then nothing for weeks at a time. Well, that seems to have ended – I’m getting spam every day now. I knew it was too good to be true. Fortunately SpamKarma2 is doing a great job of finding it and quarantining it so I don’t have to continually check. And it’s pretty good about not having false positives either – comments that it thinks are borderline spam are given a chance to fill out a captcha and then that comment gets through, and subsequent comments from the same user are given a few positive points. So I’m actually relieved that the expected has happened, and it hasn’t inconvenienced me much.

Wiki!

While I liked Michael Greb’s suggestion of trac, it seemed like an awful lot of work to set up, since I don’t currently use subversion and I have no idea how to set that up. So I went for an easier solution and installed TWiki. It seemed easy enough, except for the fact that it’s got two “Webs” devoted mostly to settings, tutorials and the like, Main and TWiki. It would make more sense to me if all that stuff was in one place and the main Web was free for you to edit as the main purpose of the site.

Maybe if I’d seen Jen’s comment earlier I would have tried DokuWiki instead. It seems to compare favourably if you look on WikiMatrix.

So anyway, the NavData Wiki is now set up here. So far one person has already found it and started to contribute, much to my surprise because it hadn’t been announced yet.