Author Topic: GPS data comments  (Read 6050 times)

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Offline ScottMorris

GPS data comments
« on: June 09, 2004, 06:26:00 pm »
Hi,

I was pleasantly surprised to find GPS waypoints and routes for the GDMBR in a format that my program can read (I'm one of the authors of TopoFusion).  This is too cool!!  Excellent job Fred and others involved with the project!

We will be riding the GDMBR this summer (south to north) and following the waypoints along the way.  I'll be recording a track log the whole time (or trying to at least).  If all turns out well, I'll make the data available to those interested.

My only comment so far is that perhaps the route waypoints could have a different naming convention than the points of interest (bike shops, campgrounds, etc) so that it is easier to differentiate them.  I suppose that is what the symbols are for.  After seeing these files I am finally motivated to add graphical support for different symbols in TopoFusion (currently it can deal with them but won't show the graphics).

Again, good work.  I can't wait to get out on the trail.

Scott Morris
www.topofusion.com

Offline Fred Hiltz

GPS data comments
« Reply #1 on: June 10, 2004, 10:03:25 am »
Hi Scott. It is a pleasure to meet another bike freak/GPS geek. Your GDMBR waypoint corrections and track logs will be most valuable. It's no surprise that the maps and aerial photos of the off-road sections are less complete and less accurate than the country's road maps. I would much appreciate any data that you can contribute to the next revision of that route. Send it to Adventure Cycling or to me (fhiltz at yahoo dot com).

We did consider coding waypoint type into the waypoint names, but ran into the inevitable design compromises. Our lowest common denominator target is a non-mapping GPSR limited to six-character waypoint names and supported by non-mapping management software like G7ToCE and others that run on a small PDA.

Providing world-wide unique names and a route-riding sequence that works without a map won out over waypoint typing in that limited namespace. Hence the use of the symbols.

I envy you this summer's ride. Have a ball, stay safe, and bring back lots of pictures along with all those waypoints and tracks.

Fred Hiltz


Offline ScottMorris

GPS data comments
« Reply #2 on: June 11, 2004, 07:49:48 pm »
I will endeavor to collect a complete log of the route, but knowning all the things that can go wrong in the process, it's likely to be far from perfect.  We'll see if the GPS 60CS is up to the task.  I am impressed with the battery run times I have got with it.

Hopefully I'll also have plenty of pictures to georeference on the route as well.

For the naming, I was only suggesting a difference between naming for the route (turns, etc) waypoints and the services waypoints.  Maybe just the leading character or something.  But it's not a big deal.

Still knee deep in water/day planning research for New Mexico.  It looks like some arduous riding is ahead of us.  Having the route defined combined with access to Terraserver's maps (through TopoFusion) is proving quite useful.  


Offline Fred Hiltz

GPS data comments
« Reply #3 on: June 12, 2004, 09:35:38 am »
Thanks, Scott. Don't trust the off road waypoints any further than you can throw your map. You may be the first to field-check the GPS data. A lot of folks will appreciate your results.

Playing with MapSource, I saw that the 60C can hold US Topo maps for the whole GDMBR. Impressive! Now, if Garmin would give us 3000 waypoints...

Fred


Offline ScottMorris

GPS data comments
« Reply #4 on: June 12, 2004, 10:59:55 am »
I haven't tried loading all the maps yet, so that's good news.  

Ah, so I suppose an obvious relevant question is how were the route waypoints determined?  As far as I have followed them (to Plataro), they seem pretty reasonable as far as aerial photographs go.  The topos seem to be quite out of date in many cases, but the route "makes sense" if you look at the aerials.

But, my paper maps are on the way.  Thanks.


Offline Fred Hiltz

GPS data comments
« Reply #5 on: June 13, 2004, 08:52:34 am »
The Adventure Cycling maps are too small-scale for positioning waypoints. Off road, I used aerial photos, USGS topos, USFS maps, and route distances from the ACA narratives. They usually confirmed one another quite well, but occasionally the chosen location was the most likely, or the one that makes sense. There's nothing like being on the ground.


Offline ScottMorris

GPS data comments
« Reply #6 on: July 07, 2004, 02:53:50 am »
Hey Fred,

Greetings from Silverthorne.  Your GPS points thus far have been amazingly accurate.  Job well done, I'd say!

There are a few minor corrections that I can help you out with when I'm done riding, but for now you can check out the data at:

http://www.topofusion.com/DivideGPX_07_06_04.zip

I'm sampling at 7 seconds / point, so it's quite a bit.  You might want to use TopoFusion to view it.  Send me an email about a free copy.


Offline Fred Hiltz

GPS data comments
« Reply #7 on: July 08, 2004, 01:51:52 pm »
Scott, your data look great! I plugged them into my copy of the GDMBR and had a good look. There is remarkably little multi-path error, I guess because the Southwest is rather open land.

Do keep the data coming. You are indeed the first to field-check the waypoints, so I will look forward to your corrections when it is all over.

Everybody, if you want to follow along, you can see where and when Scott:
  - Got started
  - Quit for the day
  - Had breakfast, lunch, and dinner
  - Missed a turn
  - Went back for something (someone?)
  - Got off and walked

Get the route and waypoints at http://www.adventurecycling.org/routes/gps.cfm and plug in Scott's tracks. Privacy? What privacy?

GPS is neat, Scot, but the riding is #1. How is it going?

Fred


Offline ScottMorris

GPS data comments
« Reply #8 on: July 10, 2004, 02:33:50 am »
Riding is definitely #1.  Besides seeing how slow (2 mph) I climb at times, and where we went backwards (we left a camelbak in a motel in Cuba, doh!), you can read and see some pictures at:

http://www.topofusion.com/news.php

The trip is going very well.  The only bad part is that it will eventually end.

This message was edited by ScottMorris on 7-10-04 @ 1:34 AM