Category: Flying

Nav data update

I’m testing a new update script for my navaid.com waypoint database. The old update scripts were written for when I was running on MySQL, and I’ve switched to PostGIS to support the new iPhone version of the CoPilot flight planning program. One of the salient features of the new iPhone version is that it attempts to be smart about downloading waypoints as you need them. One of the ways it does that is by asking my server for all the points in a particular area that have changed since a given date. The app keeps track of all the “areas” it has seen, and when the last time it was updated, and asks for an update of those areas at certain intervals. But that means I have to keep track of when a point was last updated. It also means that I need to keep track of what “area” a point is in. For the areas, I use a pseudo-quadtree where I allow only 500 points in an “area”, and when it gets more than that I split the cell into four sub-cells and mark the original cell as “superseded”. The new sub-cells have a “supersedes” value, so if the app asks for an area X, and area X has been split, I can say “X has been superseded, and here are the area ids A, B, C, and D that supersede it.”

But all this means that my new update scripts have to get the new data for a waypoint, figure out which old waypoint it was equivalent to (even if the waypoint has been resurveyed and is at a slightly different location and/or it has changed id), and only save the point anew if something significant has changed. Oh, and if the new data is missing information that the old data has, try to be smart about keeping the old data – for instance, George Plews’ Airports In Canada web site has data for airports in Canada that I can’t get any other way, but it’s also got data for airports that either were in the DAFIF data or are in the FAA data, and those two data sources often have much more information about runways and communications frequencies that Plews doesn’t have. So I want his latest data, but I don’t want to lose the other stuff that he doesn’t.

One of the things I do to match up the old with the new data is look with a bit of geographic “slop” – in the case where the ID matches I look within 0.05 degrees latitude and 0.05 degrees longitude (which believe me, in Alaska is way too big an area), and if the IDs don’t match, I look within 0.025 degrees longitude and 0.025 degrees longitude. These numbers were chosen extremely arbitrarily, and still causes a bit of a problem with a couple of airports that are near the US/Canada border because when I’m loading the FAA data it changes some Canadian airport to the nearby US airport, and then when I load the Plews data it changes it back.

Testing out my load scripts, I discovered two things:

  1. Sometimes the resurveyed point has moved enough that it’s in a different “area”. And that’s going to confuse the hell out of the algorithm that the app uses for getting updates, because it will ask for updates for the old area, and not get anything for that point. That’s going to require some thought to fix.
  2. In the next FAA data load, they’ve actually moved a couple of airports by 1.0 degrees of latitude or longitude. And judging by what I’m seeing on the Our Airports site maps, it appear the new values are correct, so the old ones must have been a data entry error. In this case, my “match the old” algorithm didn’t find anything to match within its radius of action, so it made a new point and marked the old one as deleted. The app should deal with that nicely.

Hmmm. Need to think how to handle this…

AvMap EKP-IV complaints and kudos

I’m using this post to track the problems and user interface deficiencies that I’m having with the AvMap EKP-IV.

  • The damn CF card is busted, and they they’re currently giving me a run-around instead of sending me a new one! was busted, and the replacement came with a return envelope that wasn’t postage paid.
  • There should be a single keystroke to get to the currently active flight plan, instead of having to hit “Menu”, “Menu”, “Flight Plans”.
  • You should be able to name flight plans.
  • Calling the button for the nearest airport “Page” is stupid.
  • Hitting the “nearest” button twice should take you to the nearest airport button instead of forcing you to hit “Page”, “Menu”, “Airport”. If you need the nearest airport, you generally need it FAST.
  • Why do I keep end up in the cursor mode just about every time I go to the map page, even if I haven’t touched the joystick? It should only be in a cursor mode if I move the cursor with the joystick.
  • The joystick is way too sensitive.
  • There should be a half-arc on the display with DTK and TRK on it like the Garmin 296 and 530W have. The only thing close is to use up a lot of screen real-estate for a HSI display.
  • The way the vertical navigation works is stupid – as far as I can tell, you have to put in the top altitude, the bottom altitude and the glide slope every time you use it. In the Garmins, you just say “I want to be at 1000 AGL when I get 3 nm from the airport, and I want to descend at 500 fpm”, and it calculates where to start your descent based on your current altitude and the altitude of the airport.
  • The manual wasn’t included in the box, even though the Quick Start booklet said it would be.
  • The manual, which I downloaded from the web site, sucked rocks.
  • The power switch evidently turns itself on if you just breathe on it. I’ve discovered the batteries dead numerous times, and it’s just sitting on my flight bag.

I’ll probably think of others.

To answer Gordon’s question in the comments below, what I like about the EKP-IV:

  • It has a really great screen. It’s big, it’s bright, and it’s very clear
  • Even better, it’s in “portrait” mode. My original GPS, a Garmin 195, was in portrait mode, and I never understood why they went to landscape mode for later models. I don’t know about everybody else, but I want to see where I am and where I’m going, not where I am and 30 miles to each side. And the AnywhereMap Travel Companion and the new Bendix King AV8OR are landscape mode too. I don’t get it.
  • It’s about the same price as a 296, much cheaper than a 396, 496 or even a 495. I don’t need XM WX yet, but if I do, I like the idea that it will someday be an optional extra on this unit, rather than having to make the decision at purchase time like the Garmins.
  • It was strongly recommended by a friend who had one, sold it to buy a 496 for the weather, but then wished he’d kept the EKP-IV.
  • It doesn’t have a road mode. That way I won’t be tempted to leave it on the dashboard of my car. Let the next car thief steal a Nuvi or other car type GPS and leave my aviation GPS alone!
  • I looked longingly at the AnywhereMap new iPaq Travel Companion, and while it had some amazing features, it was incredibly slow. This one looked like it had some of the features, without the horrible slowness.

Oshkosh purchases: a mixed bag

Update: Did I sound a little annoyed with AvMap when I posted this? Well, I suppose I was. But I think I’ve finally managed to convince the support person that I’ve done everything I can, so they’re finally going to send me a new CF card. So I’m a lot less annoyed. I still wish there was a way to get them to listen to my ideas about the user interface, though. It doesn’t seem right to open a support ticket for that, but there isn’t anything else I can see on their web page for other feedback.

I made three major purchases at Oshkosh.

  1. iCom A14 handheld radio
  2. Clarity Aloft headset
  3. AvMap EKP-IV GPS

It’s been a mixed bag.

The iCom worked out of the box, I was able to use it on the trip home, and now I’ve had a chance to go through the manual it looks like it will do everything I need and then some (I didn’t know about the automatic marine weather mode, for instance). It’s slightly annoying that the free headset adaptor is a mail-in thing, and I have to make copies of the sales receipt and registration card.

The Clarity Aloft didn’t work, and I didn’t discover that until I fired up the engine for the flight home. I wrote to them as soon as I got home and they were very apologetic. They shipped a replacement immediately, and it arrived today. I took it out to the airport to make sure it worked fine, and it did. They didn’t send a pre-paid return shipping slip, so I’m going to have to pay to return the broken one and get reimbursed. I’m going to keep the extra eartips from the first one as a compensation for my troubles.

The EKP IV did work, after a fashion. There are a few items of the user interface that absolutely drive me bonkers, and a few that are minor annoyances. After I got home, I thought I’d grab the latest firmware to see if some of the worst bugs have been fixed. That involves putting the CF card in a card reader on my computer and copying some files over. Seems simple enough. The manual suggests very strongly that you keep a copy of the files on your computer, so I did. But after updating the CF card and putting it back into the unit, though, the unit says “DEVICE not PRESENT”. (Yes, that’s the capitalization.) I tried restoring the backup files, but it didn’t help. I tried copying the files to a different CF card, and the unit boots with it, but can’t access the aviation database – that’s not entirely unexpected, because the aviation database is somehow keyed to the CF card. The problem is that I just can’t seem to convince the AvMap people that the CF card is toast and I need a new one. I’ve exchanged a number of emails with somebody in Italy where I set out my very strong evidence that it’s not what I’m doing, or the version of the firmware I’m using, and they send back instructions that basically assume that I’m doing something wrong or using the wrong version of the firmware. If they don’t ship me a new CF card in the next 24 hours, I’m going to go to my credit card company and get them to cancel payment on this. And then I’m going to buy a reconditioned Garmin 296 or a 496.

Sometimes I should just leave well enough alone

I went to register my AvMap EKP-IV GPS. While doing so, I noticed that the firmware I have is a couple of version numbers older than the current downloadable one. Upgrading is supposed to be a simple matter of popping out the CF card, putting it into the computer, and copying over the two files you download, and then putting the CF card back in the GPS. Well, I did that, but then the GPS started saying “Device not found”. So I copied back the original files, which I’d copied onto my laptop as suggested in the documentation. And I got the same damn message. So now I’m basically boned.

The instructions were all about “Hilight the two files and drag them”, but I used “cp -R”. I wonder if there is a permissions problem? I knew I should have made a tar file instead of just a copy.

Back from Oshkosh

I’d gotten an STMP (or whatever it’s called) reservation for an IFR departure at 1715Z. But by 1400Z, there just wasn’t that much left to do around the campsite, and I didn’t want to buy another day’s ticket. So I went down to the gate house, got my camping refund (they make you pay for the whole week in advance, then give you a refund when you leave), got a weather briefing, and took a shower, then got ready to depart VFR to see if I could pick up flight following from Muskegon Approach.
Continue reading “Back from Oshkosh”