How to create an overlay Garmin 680t

RanOutofTalent

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Dec 20, 2014
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Western Montana
I have a Garmin Montana 680t and want to be able to add the sled trails for places like Togwotee to be a permanent part of the map so when we are following an old set of tracks or boondocking I can see how far we are from the trail system

I have basecamp and google earth. I have found

http://wyoparks.state.wy.us/index.php/snowmobile/snowmobile-maps-trails

here there are GEOPDFs, I have been told there is a way to add them in.

Any help would be much appreciated

Thanks
 

LudicrousSpeed

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Jan 5, 2012
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I tried to export the data out last year to get a track as what I have seen for the overlay was that you take an image which does scale well when you zoom in and out. I was meaning to get back to this and get the wyoming area imported. Will follow up after the weekend.
 
I have a Garmin Montana 680t and want to be able to add the sled trails for places like Togwotee to be a permanent part of the map so when we are following an old set of tracks or boondocking I can see how far we are from the trail system

I have basecamp and google earth. I have found

http://wyoparks.state.wy.us/index.php/snowmobile/snowmobile-maps-trails

here there are GEOPDFs, I have been told there is a way to add them in.

Any help would be much appreciated

Thanks
So here is my advice...

Migrate away from only a handheld GPS and towards a handheld and a cell phone that can run Google Earth. The issue is that the handheld GPS units have poor performance in terms of OS, and how external maps and image overlays are handled. For instance Garmin has massively tight restrictions on the size of the .jpg (and only .jpg apparently) file size, both in resolution 1024x1024 pixels max, and a file size cap of 3mb per .jpg file. As you can imagine this severely limits the quality of the file(s) used for trail map overlays. Garmin does allow 100+ overlay images which can apparently be tiled (chopping the overlay up in to 1024x1024 pixel chunks), depending on which unit, but that is total for all map files and also a huge pain in the keyster to build in Photoshop/Google Earth. An Android or iOS phone on the other hand can download an entire .kmz file with massive image overlays no problem . This allows processing of the trail map files in good resolution and in single .jpg images. In addition to Google Earth on a mobile device, file and overlays download when in data service and should persist on the phone if data service is lost out in the boonies. In addition to Google Earth I recommend using an app such as GPSLogger ( https://play.google.com/store/apps/details?id=com.mendhak.gpslogger ) to log your riding data. GPSLogger allows you to save directly to a .kml file so that you can import it into Google Earth. I have included a GPSLogger trail of a ride I did in April 2013 up in Alaska near the Johnson Creek area in the .kmz example file below.

I have downloaded the Continental Divide - Tetons GEOPDF and converted it to .jpg, then imported it to Google Earth as an image overlay. I have done my best to tie it's points accurately to Google Earth (a bit of a time consuming task). For most of the northern half of the map the trails should be within a hundred feet or so of accuracy. I have added that trail map to the file I have for Island Park/West Yellowstone area and the South Dakota Black Hills area. Both maps are a few years old however. You are welcome to give it a look on a desktop version of Google Earth and try to load it as a custom map (unlikely that it will work due to the above mentioned limitations of Garmin...) in your GPS unit. I have tested the .kmz on my Pixel 3 XL and all three map areas showed up with the overlays.

https://www.nealmastel.com/trailmaps/SnowmobileTrailMaps.kmz

You can obviously toggle off the overlays you don't wish to have on at any one time, or in Google Earth you can highlight an individual overlay and save the place as an independent .kmz file.

If anyone else wishes to have me add a trail map overlay I can do so and compile a .kmz that has as many trail maps as people are interested in.

:beer;

Neal
 

Lissandragaren3

New member
Jan 7, 2019
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So here is my advice...

Migrate away from only a handheld GPS and towards a handheld and a cell phone that can run Google Earth. The issue is that the handheld GPS units have poor performance in terms of OS, and how external maps and image overlays are handled. For instance Garmin has massively tight restrictions on the size of the .jpg (and only .jpg apparently) file size, both in resolution 1024x1024 pixels max, and a file size cap of 3mb per .jpg file. As you can imagine this severely limits the quality of the file(s) used for trail map overlays. Garmin does allow 100+ overlay images which can apparently be tiled (chopping the overlay up in to 1024x1024 pixel chunks), depending on which unit, but that is total for all map files and also a huge pain in the keyster to build in Photoshop/Google Earth. An Android or iOS phone on the other hand can download an entire .kmz file with massive image overlays no problem . This allows processing of the trail map files in good resolution and in single .jpg images. In addition to Google Earth on a mobile device, file and overlays download when in data service and should persist on the phone if data service is lost out in the boonies. In addition to Google Earth I recommend using an app such as GPSLogger ( https://play.google.com/store/apps/details?id=com.mendhak.gpslogger ) to log your riding data. GPSLogger allows you to save directly to a .kml file so that you can import it into Google Earth. I have included a GPSLogger trail of a ride I did in April 2013 up in Alaska near the Johnson Creek area in the .kmz example file below.

I have downloaded the Continental Divide - Tetons GEOPDF and converted it to .jpg, then imported it to Google Earth as an image overlay. I have done my best to tie it's points accurately to Google Earth (a bit of a time consuming task). For most of the northern half of the map the trails should be within a hundred feet or so of accuracy. I have added that trail map to the file I have for Island Park/West Yellowstone area and the South Dakota Black Hills area. Both maps are a few years old however. You are welcome to give it a look on a desktop version of Google Earth and try to load it as a custom map (unlikely that it will work due to the above mentioned limitations of Garmin...) in your GPS unit. I have tested the .kmz on my Pixel 3 XL and all three map areas showed up with the overlays.

https://www.nealmastel.com/trailmaps/SnowmobileTrailMaps.kmz

You can obviously toggle off the overlays you don't wish to have on at any one time, or in Google Earth you can highlight an individual overlay and save the place as an independent .kmz file.

If anyone else wishes to have me add a trail map overlay I can do so and compile a .kmz that has as many trail maps as people are interested in.

:beer;

Neal
I tried but unlucky that I can not, Do you have another way?