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I have had a Garmin Dakota 20 for a few years now. I have a 2008 map of Thailand installed.

I have just downloaded BaseCamp and whilst researching some issues came across OSM.

I was wanting to update my Thailand map by buying an updated version from Garmin but am wondering is this necessary if there is OSM available for free?



asked 12 Jun '13, 05:53

paulringer's gravatar image

accept rate: 0%

edited 12 Jun '13, 17:42

gormo's gravatar image


You would first have to look at the OSM main map and determine if the data quality is good enough for your purposes.

For hiking in the European Alps, OSM is defineately not suited everywhere. Some areas are mapped quite good, others less so. You really would have to check on a case-by-case basis if OSM data suits your needs.

In some german cities, for example, OSM is (in my opinion) the absoultely best data available.

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answered 12 Jun '13, 12:03

gormo's gravatar image

accept rate: 13%

I'm guessing that means I'd be safer to get an update :)


(12 Jun '13, 12:36) paulringer

I have my original Thailand gmapsupp.img in both internal, SanDisk memory as well as on CD. I am however dammed if I know how to upload/transfer it to BaseCamp no matter how much reading around the subject I've done on the very informative pages I've found and been directed to over the last 48hrs.

(13 Jun '13, 03:30) paulringer

you need to install the Thailand map from CD into Basecamp / Mapsource. You will also need to install the OSM map for Thailand into Basecamp / Mapsource. Once both are installed, you then need to use the map tile select tool to select the tiles from both products. The click on the <send to="" device=""> button to create a new GMAPSUPP.img file containing both products on your device. You will now be able to switch between products from the setup map menu on the map screen. I have used this approach on my GMAP72 and it works great.

(13 Jun '13, 07:08) rovingmedic

with basecamp running and dakota connected, with micro sd installed, i believe it automatically goes into mass storage mode, in basecamp click on receive from device, wait a while click on maps, click map products and you can then select the available map or maps. If you later download an img file for direct installation to the micro sd that map would also be seen when you connect via basecamp.

(13 Jun '13, 07:27) andy mackey

The instructions with these GB maps will help you get it right.

(13 Jun '13, 07:31) andy mackey

@rovingmedic: that Basecamp method may also work, but there is no need for Basecamp here. It also works simply with several img files. I think this is easier.

(13 Jun '13, 22:09) aseerel4c26 ♦

I'm not sure how, but I have successfully installed the OSM generic routeable gmap to BaseCamp. I still can't seem to get the Garmin map from CD or device, I keep getting

/Volumes/1PL028656/English Language Map/Garmin/gmapsupp.img" could not be imported.

When I try.

(14 Jun '13, 07:30) paulringer
showing 5 of 7 show 2 more comments

I recently used the OSM for Garmin maps during a visit to Bangkok. I found the maps quite good. You can download them from this site (they are updated weekly):

The great thing is that you can correct any error / omissions yourself and benefit form the update very quickly. Garmin only issues updates about 2 to 4 times per year, and each one will cost you money.

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answered 12 Jun '13, 08:23

rovingmedic's gravatar image

accept rate: 5%


Also, you dont have to give up on your Garmin map yet if you are unsure : just save the Garmin file someplace before puting the OSM one in. With proper setup, you can even keep both maps on the device and switch at runtime.

Note that there are many different "renderings" of OSM maps for Garmin. If the one you tried isn't as good as you'd like, try a different one or make your own using mkgmap.

(12 Jun '13, 08:40) Vincent de P... ♦

Many thanks Rovingmedic & Vincent.

As I generally use my Garmin for "off the beaten track" bike rides would the OSM still be as useful? I noticed there was a cycle layer on the "big map".

How would I store 2 different maps? Using 2 slightly different file names and storing in my Garmin file? Could I then swap between the 2 by enabling and disabling in the settings menu?



(12 Jun '13, 10:54) paulringer

As gormo say if the map is good enough. If not you could improve it. The map swapping you suggest should work on the Dakota, it does on a Garmin Nuvi 1310t as I can switch between city navigator map and OSM, but on my Vista HCX I would have to do the re-naming by connecting it to a PC as it will only recognize and load one map called Gmapsupp.img

(12 Jun '13, 14:14) andy mackey

@paulringer: different maps? See What if I have an existing gmapsupp.img file?. The older devices can handle only one .img file which need to be named gmapsupp.img (renaming the files with a PC is possible to switch the active map, of course). Info about your Dakota 20: "You can add more than one map file just by giving it a different name e.g. gmapsupp1.img gmapsupp2.img". So you can just switch between several maps as you imagined.

(12 Jun '13, 15:01) aseerel4c26 ♦

By different maps I meant 1 say generic Garmin Thailand gmapsupp.img and then maybe an OSM Thailand map with just the cycle route layer.

I have discovered/learnt over the last day that when I plug my device in to my Mac the reason Dakota 20/Garmin shows up and another entity NO NAME shows up is 1 is the internal memory for the Dakota and the other is the SanDisk, which apart from the gmapsupp.img image file is completely empty.

Does storing 1 or more maps in a different location make any difference if the file names are different?

(13 Jun '13, 03:29) paulringer

@paulringer: Using both locations should (*I* don't have this device) also work. As long as you see both maps in your device's settings it is fine. If you want to only use the card (SanDisk) you can rename the image files to different names. Generally regarding multiple maps: To my knowledge you should only set one map to "active"/"enabled".

(13 Jun '13, 22:07) aseerel4c26 ♦

@aseerrel On my garmin oregon 450 similar age to Dakota model I usually have two maps activated/selected the purchased map is a raster map and has a higher draw order and shows on top of the other map that is a free openstreetmap on garmin download that is routeable. I select a point on screen of the device it will generates an high lighted route ( after i have chosen from direct, automobile, motorcycle, cycle, tour cycle, mountain bike pedestrian, hike,mountaineer or ATVOff road driving!).

(16 Dec '16, 08:58) andy mackey

Routing also works over a Garmin Custom map if there is an activated routeable map enabled as well.

(16 Dec '16, 09:00) andy mackey
showing 5 of 9 show 4 more comments

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question asked: 12 Jun '13, 05:53

question was seen: 11,461 times

last updated: 16 Dec '16, 09:53

NOTICE: is no longer in use from 1st March 2024. Please use the OpenStreetMap Community Forum