Transparent Trail Map help needed

[JonWillard]

Hi,

I have downloaded both the OSM trails and the 100K trail transparent maps.  I can see the trails in MapSource when I zoom in but when I select/transfer the maps to my Garmin GPSmap 60C I cannot see the trails.  I have tried various combinations of downloading topo maps and the transparent trail maps, I have also tried just downloading the transparent trail maps.  I do not seem able to see the trails on my GPSr.

I did read the tutorial on how to chose which maps are viewable and I have played with that too and the trails never show up.  It seems to me that one of 3 things must be true:

1. I am not doing something correctly
2. The transparent maps do not work
3. My GPS does not know how to use the transparent maps

Any/all advice welcome.

Jon

[JonWillard]

Here is some more interesting data, I hiked Baxter State Park in Maine recently with my GPS on and when I use MapSource to view my tracks against the trail 100K map for Maine they do not line up.  I use Nad27 Conus, UTM on my GPS.  Is it possible that the skew is from using different coordinate systems? 

The trail 100K maps are several miles skewed from my actual tracks.

[maps4gps]

Did you zoom into 500' or closer on the GPSr?  Did the mapset(s) get transfered to the GPSr?  Are they set to display?

With over 6500 downloads it is unlikely.  Yod did say they displayed in MapSource.

Most/All mapsets use NAD83/WGS84.  The GPSr should do the conversion in the background.  The difference between the two is less than 100' in most locations.  Miles off for which mapset?  A user in VA? reported the 100k being off more than the source scale would indicate they might be, but when he checked in my area (CO), they were right on; as were mine.  The OSM data is submitted by users to the OSM site; could be a user gave bad data.  If the 100k mapset has the issue; are you sure the trail shown miles away is supposed to be the one you were on; how does it's position compare with the printed 100k?

[JonWillard]

Here is a MapSource screen shot:

The gps route is marked in pink, the tracks are brownish/red and the trails are brown dashes.  I did this loop in pink but as you can see the trails are skewed several miles to the right.  The knife edge trail is the loop in the lower left, and you can see a trail for it in the lower middle.  They do not line up at all. 

Now I know it's wrong because the trail that I have a track for is the trail on the far right of the screenshot.

Pretty weird.  the trail map is the 'Trails from 100k maps'.

[jbensman]

You are right, the 100K map is way off.  100K data is normally not that accurate (lots of the 24K data is also not very accurate).  But something is messed up on that map.  Comparing it to Garmin's 100K topo maps Maine is not the only state that is messed up.  Everywhere I checked in the NE is WAY off

I did a quick search and on the Main GIS site they had a shapefile for trails in Main.  So I made a state trail map for Maine in my trails.  There are no labels for anything and the only thing I coudl figure out how to label was 4WD trails.  It looks like the same data in the 100K map, but in My Trails, they are where they are supposed to be.  So download My Trails and see how it works.  I just uploaded a new version that has Maine in it.  If you can find other or better data for Maine, let me know.   

[JonWillard]

I have not yet been successful find good trail maps for Maine or New Hampshire.  If you know of anything please let me know!

I am glad that you were able to confirm the problem.

Regarding the 'other' problem of not seeing the trails, it might be because of the skew and I am looking in the wrong spot. 

[maps4gps]

Just checked this area by downloading a raster image of the Oakfield 100k.  There is a huge difference between the two.  In checking my local area the fit is good (almost exact). 

Jim,  have you noticed such a huge difference in other parts of the country?

[JonWillard]

I can see the trails on my GPSr now that I know where to look for them, 2 miles east :-)

Is this something that can/will get fixed or is it not fixable?

Thanks for all of the responses guys.

[JonWillard]

Hi Jim,

I read your post more carefully  and downloaded My Trails.  It looks much better for Baxter State Park.  Thanks so much...

I an not sure how New Hampshire lines up ... but I hike mostly in Maine and New Hampshire.  Any chance you can make that available if it needs a fix?

Anyway thanks for the GREAT support!

[maps4gps]

Depends on what caused the issue.
First would be to determine the extent.
I will not have a chance to look into it until sometime next week.
Does the 'trails from OSM files' have anything to help?

[usman1]

Great tool. Thanks a lot!

[jbensman]

They seem fairly close in IL, but I noticed they were off all the way in NY.


Jon,

The only thing I could find in NH was the White MT National Forest and the AT.  I could not find any other state data.  So I made a NH map with just the AT (trail, parking and shelters) and trails and a bunch of other stuff in the NF.  I have roads, snowmobile and Xcross country ski paths that I have not figured out what to do with to.  So none of it is on the map yet.  The AT data is GPSed and the Forest Service data also appears to be GPSed.  I also added the AT data for Maine.  When I was removing the parts of the AT that was already on the map, you could really see why I do not like to use 100K data-it is generally not very accurate.  I also added a bunch of NPS data for Arcadia NP.  It appears to be GPSed so it is also very accurate.  I've got another good source of data that has a buch of trails for ME and NH, but they only allow 5 trails per email a day.  Send me a PM with your email if you want to help me get the files. 

You can alsways GPS something and send it to me to add to or correc the map.   If you want you could also spend some time searching ME/NH state sites (or sometimes city/county) and see if you can find any data.  Look for shapefiles. 

[jtkt1981]

A couple of quick spot checks in Indiana seem fairly close too.

[maps4gps]

Thanks for the info.  I am hoping it is just UTM zoon 19 (-72 to -66 degrees) and that something unusual happened in the conversion.

[maps4gps]

New version correcting the issue has been uploaded.