How were you able to get the one-ways out of the Tiger data? The best I could see was a guarantee that a road was a two way, but nothing to determine if it was a one way -- the difference between divided, undivided, separated, and unseparated from the Tiger fields (basically whether each direction has a distinct edge in the data or not)

That's still work-in-progress. There might a way of giving a good guess whether road is a one-way or not, but there probably are cases where it does not work. That's why all streets are classified as two-way, for now. Though, the software has support for one-ways, if I just figure a way to determine that from the data.

Kim

I'd still like to remind that the route planning is not perfect -- or even near perfect. It has trouble guiding through some places, especially near complex junctions.

The main problem is that all guidance is based on the 2D vector map. There's no real information on crossroad or junctions. Everything is based on lines and line segments. The map conversion software figures out which roads connect to other roads, mostly based on angular differencies.

This problem has been overcome with the real navigation CD's in a way that all crossroads and junctions are modeled and they are gived a certain type. Therefore, you can determine upcoming crossroads more easily and also know what type of crossroad it is, and give better guidance.

Kim

I'd still like to remind that the route planning is not perfect

That is probably why it told be to turn left on the freeway today. Man that would have been painful :-)

Do you have any ideas/plans on how to work around that? Or does this mean that we would need commercial map data and you would have to update your software to deal with the extra data?

-Mike

That is probably why it told be to turn left on the freeway today. Man that would have been painful :-)



Do you have any ideas/plans on how to work around that? Or does this mean that we would need commercial map data and you would have to update your software to deal with the extra data?

Well, first thing would be to catch a small log around the area where that happens so that I could take a look at that particular case. It can be made better, I'm sure, but I don't think it will ever be as good as a system that knows more about the crossroads and junctions.

In other words, if there would be support for real TeleAtlas data (or similar), then there would need to be extra code for handling that -- and then in perfect world, it wouldn't ask you to turn left on freeway

Kim

Awesome! I can't wait until the missing links are pieced together! Is the map data the only thing keeping it from a wide release right now?

I think the way this goes forward is that I'll try to overcome the biggest problems with Mike now, and then probably take another 1-2 testers from US area and see further then.

Kim

In reply to:

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In other words, if there would be support for real TeleAtlas data (or similar), then there would need to be extra code for handling that -- and then in perfect world, it wouldn't ask you to turn left on freeway

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I am working on that, I am trying to get ahold of resellers for these GDF CDs - but it seems that none of them wants to do business with me. Seems my last name has to be Volkswagen in order to get a price quote.

Till

In reply to:

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In other words, if there would be support for real TeleAtlas data (or similar), then there would need to be extra code for handling that -- and then in perfect world, it wouldn't ask you to turn left on freeway

---

I use TeleAtlas maps in my Carin and had 2 occasions so far where she asked to "Turn around if possible" on a freeway.

What exactly do you need, just a CD or the specs/format ? I must have an old Benulux CD lying around here somewhere (98) which I could mail/ISO upload to you.

What exactly do you need, just a CD or the specs/format ?

Both . I've talked about the problems with existing navigation CD's in other threads, but mainly the problem is the lack of format specs. Some people are trying to obtain TeleAtlas CD's in GDF-AS/GDF-AR format, which has specs available and should be more useful.

I must have an old Benulux CD lying around here somewhere (98) which I could mail/ISO upload to you.

I'm afraid the format is pretty unknown for that as well. Though, you can send me one or two of the files from the CD (which look about the right data), and I can verify this.

Kim

I haven't seen anyone mention this yet. Not sure if it is usable but it looks like map data is available from TIGER.

I also have Precision Mapping Streets 3.0 and DeLorme Street Atlas USA cd's if you are interested in taking a look.

A quick search on google and I found some relevant links.
http://www.frontiernet.net/~werner/gps/
http://vancouver-webpages.com/peter/

Tom

I haven't seen anyone mention this yet. Not sure if it is usable but it looks like map data is available from TIGER.

(Smartass comment) Might want to take a look at the subject of this thread, we are talking about the tiger data (end smartass comment)

Or did I miss your point?

-Mike

Um, doh.

I guess I’ll blame me for skimming this too quickly. Hard to keep up with all these posts!

Tom

I REALLY want to see this working with widely available maps, just for selfish reasons - turns out my US Blaupunkt nav unit is incompatible with the European map CD's.

I am a little concerned that all commercial in-car nav units supplement the GPS data with accelerometers and speed sense input, though..

Rob

Damn, you seem to have been driving around pretty much the same streets I was driving around on that date. I need to get this loaded up with a UK map!

Rob

I am not really familiar with the Tiger file format and frankly my experience is more on the GPS side and less on the vehicle navigation side of the problem. Has anyone looked at the Garmin map database, available from Radio Shack and others for $150, for the US. I don't know what the level of detail is or the format.

On a related subject, can anyone give me an idea of what it would take to accept a stream of NMEA $GPRMC sentences on the Rio/Empeg serial port and display position, velocity and time on the RIO/Empeg. This is ASCII data and requires very little formatting to be useful though some units conversion would be helpful (knots to MPH or KPH).

I think that this would be a great first step and would help build further interest in this project as well as allow preliminary testing of GPS installation in cars. I appologize if this has already been covered but I didn't see it while looking through the board threads.

Sorry, but double carraige returns don't seem to show up in my posts!

Lynn

Sorry, but double carraige returns don't seem to show up in my posts!

I think it may be a function of how your browser displays them. Your double returns show up just fine on my screen, using Netscape 4.6something

tanstaafl.

On a related subject, can anyone give me an idea of what it would take to accept a stream of NMEA $GPRMC sentences on the Rio/Empeg serial port and display position, velocity and time on the RIO/Empeg. This is ASCII data and requires very little formatting to be useful though some units conversion would be helpful (knots to MPH or KPH).

Take a look at the hijack kernel mods for an easy way to display stuff on the screen. You can basically just cat text to a /dev entry.

In order to use the serial port you need to write a custom init script that starts the player with the appropriate flag to keep it from locking the serial port to output its debug info (I think it is -s but search here).

Reading from the serial port is trivial, you may have to set the speed first though.

As far as parsing the NMEA data, it sounds like you may know what you are doing already. I started to rip some code out of one of the open source gps clients (jeeps I think?) a while back to do this. IIRC I had it working aside from some endianness issues with the long and lat that I didn't know how to get around.

Now that I think about it, now that mlord has done all the UI work with hijack this should be pretty trivial to do.

-Mike

Thanks for the tips. I have read through the Hijack source twice and am thoroughly intimidated! Way beyond my skill level with software. I guess I will wait patiently for the time being.

Lynn

And it would keep the empeg cool. Nice external cooling system...hmmm

If you need a hand or any further testing, I am currently on unemployed status with plenty of time, so send me a private message

I want one.

Greg

I'm considering the purchase of a Garmin GPS 16 ... it's similar in that it's an OEM product, 12 satellites, etc. This one however will receive WAAS information from a couple of satellites over the US.

This gives it an accuracy of less than 3 meters.

Haven't found a price yet ... but it's meant for consumers.

g

looks like the gps 16 runs about $175 from web vendors.

--dan.

This looks to be a good choice. It can even be powered from the Empeg amplifier control signal due to the low current required. All you will need to do is make an RJ-45 to DB-9 adapter. Oh, and then there is the software!

Try these two sites for purchase. They both show it for $150 US.

http://www.a-nautical.com/catalog_garmin_gps.htm

and

http://www.navtechgps.com/supply/gps16.asp

I am familiar with the latter outlet and they have been around for quite a while.

Good luck,

Lynn

This one however will receive WAAS information from a couple of satellites over the US.

What is WAAS?

What is WAAS?

And while we are at it, what makes these OEM units worth the extra $50-$100? It seems like without the screen, buttons, etc then should be super cheap, but they are more expensive than my eTrex which to me seems like a pretty good unit. I assume they are not significantly more accurate since the eTrex claims accuracy within about 20 feet most of the time. So what are the extra features that increase the cost and are they useful for an in car application?

-Mike

WAAS is the"Wide Area Augmentation System" developed by Stanford under contract to the FAA. The intent is to improve the accuracy of GPS so that it can possibly be used in the approach phase for commercial aircraft. This has been under development for almost 10 years.

New INMARSAT satellites (geosynchronous) are used to transmit differential GPS correction data to remove some of the common mode range error noise. There are a geographically dispersed array of GPS reference stations that produce a set of range error contours for each GPS satellite that are then relayed through the INMARSAT links to your receiver where you calculate the corrections that are appropriate for your approximate current location.

Since the correction data is transmittesd in "L-band" as are the GPS signals the receiver is little more complicated and the performance greatly improved, however, this is much less important now that S/A (Selective Availability) has been turned off.

An OEM unit should be a little more rugged and therefore better suited for an automotive application where it can be mounted in the location that best suits the reception of the signals. Controlling it completely (power on/off etc.) from the serial port will also lead to a more finished solution.

Lynn

Thanks for the info. I am interested in getting a GPS to permanently mount in my car that can be easily turned on and off via serial or via the amp remote line on the empeg. The GPS that I am currently using has a button that needs to be held down for a few seconds to turn it on so any sort of permanent install would be tricky. However, I don't really want to spend the money for a differential unit unless it really improves navigation. Is there a more affordable OEM stile unit that is meant to be controlled by another device but without the extra WAAS features? Or would it be worth it to spring for one of the units mentioned above?

Thanks,
-Mike

I think the main reason is probably that they sell less of these OEM units to consumers that they sell Etrex units.

Patience, there is something in the wind....

That would be really neat

Besides, i'd rather use the hardware I have and buy a small app from a BBS member than purchase a dedicated unit that won't work quite as well.