GPS Data Files? YIKES!

[Spokes]

Will someone help explain to me if the entire ATC centerline GPS data file for the AT or say the entire PCT GPS waypoint file will fit on a Garmin Legend HCx or will I need to load separate smaller files? Do these files get loaded onto the SD card (I think it takes up to a 4 gigs)?

Obviously, I'm totally confused.

[leaftye]

It's more about the number of waypoints. I believe Halfmile does his PCT waypoints by state to keep the number of waypoints below the cutoff. I think the cutoff is 10,000.

[BrianLe]

Waypoint files aren't very large; it's the actual maps themselves, the imagery that takes space. And even there it depends very much on whether you have raster vs. vector images ... a bitmap type of fixed image (raster) will be larger.

Perhaps I'm misunderstanding you, but a gpx file for the entire trail is likely under a megabyte, whereas as you point out, memory cards these days have capacities measured in gigabytes.

In terms of raster graphic maps, the required space will depend on how wide a corridor of map data you want around the trail. I had the entire AT on my smartphone this year, in a sufficiently wide corridor at 1:24000 scale USGS maps, plus I had 1:100k and 1:250k as well, and all of this fit along with other stuff (MP3 files, photos taken along the way ...) on a 2 gigabyte microSD card.

[Wise Old Owl]

You got me - I lost my Legend HCX before I got a chance to put the trail in. It should accept the At track, but not the centerline as that would require an extra chip... but that is a guess.

[Spokes]

It's more about the number of waypoints. I believe Halfmile does his PCT waypoints by state to keep the number of waypoints below the cutoff. I think the cutoff is 10,000.

This is what's confusing to me- 10,000 waypoints equals how many bytes? In other words, will I be able to fit all of Halfmile's PCT waypoint files on say a 4 gig SD card on the Garmin?

[couscous]

Garmin has been VERY slow in updating all the limits on their units. One of their best units (Oregon 550t) still only handles 2,000 waypoints and the Legend HCx only handles 1,000 waypoints. Tracks can be uploaded, but these are also limited to 10,000 total points. IMHO any GPS that supports micro SD cards should allow as many waypoints, tracks and points as the storage accommodates, or at least increase the limits tenfold.

[leaftye]

couscous, that sounds right on. It's absolutely ridiculous that they have those limitations. I do have the Oregon 550 and it's frustrating that with all the memory capacity that I can only use a small fraction of it. I have Halfmile's waypoints loaded on it, and I can't create any new waypoints. I have a bunch of maps loaded on it, but the only way I'll ever fill it is if I use it a LOT to take pictures. Actually, taking a picture is my workaround for recording a waypoint. I do have a 4 gig memory card in mine.

[perrito]

Spokes,
Don't confuse waypoints with track points. A track is made up of points to define the track, but these are independent of "waypoints".

Having a limit on tracks, points to define each track, waypoints, etc., is stupid. I wonder if this limitation could be remedied through a firmware update. It may be a legacy-type limitation from when processors were slower. I use my GPSr to geocache as well as a hiking tool. The 1000 waypoint limit is annoying for geocaching. I only get the caches for a 13 mile radius from home. You would think they'd allow you to store multiple GPX files on the unit and load the one you want to use while still having the others available if needed for loading.

When I do an AT section, I download the track and waypoints from backpacker.com but I have to chop the track into pieces with less than 500 points - the limit per track. Again - why the limits?

[Trailryder42]

If you have a GPS unit that keeps a track log(10,000 points), like the Garmin 60 series, you can trick the unit/get around the point limit/size track file you can display by renaming the file ACTIVE LOG 001 and uploading that
to the unit.

Just be sure to disable the track log record function so it doesn't overwrite your file while you travel.

[perrito]

If you have a GPS unit that keeps a track log(10,000 points), like the Garmin 60 series, you can trick the unit/get around the point limit/size track file you can display by renaming the file ACTIVE LOG 001 and uploading that
to the unit.

Just be sure to disable the track log record function so it doesn't overwrite your file while you travel.

Nice trick. I'll have to try it.