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After I install one of the pre-compiled OpenStreetMap (OSM) sets for say, North America, how will the new OSM data interact with the existing data?

I've listed some scenarios below and filled in my current best guess:

  • Road exists in Garmin, also exists in OSM: Shows up
  • Road exists in Garmin, not in OSM: Shows up
  • Road doesn't exist in Garm, exists in OSM: Shows up
  • Road differs between Garmin and OSM: ?

  • POI in Garmin and OSM: Appears

  • POI differs between Garmin and OSM: ?
  • POI not in Garmin but in OSM: ?
  • POI in Garmin, not in OSM: Doesn't appear

In addition, I've noticed that sometimes, when I try doing a OSM website search for an address that has a house number, OSM will not be able to pin down the exact coordinates. How will those situations be resolved?

Model Information

  • Garmin StreetPilot i3
  • Garmin Nuvi 265W

asked 05 Jan '13, 06:55

Zian's gravatar image

accept rate: 0%

edited 17 Jun '13, 08:32

Different Garmin devices work in slightly different ways - it would help to say which ones in particular you're asking about.

(05 Jan '13, 11:29) SomeoneElse ♦

Using an GPSMap 78 I experienced that addresses and POI are found for both maps - you get two results. It doesn't matter which map is active. But the device doesn't show directly which result is from which map. In some cases looking directly at the resulting POI you can tell from the format of the additional information if it is from Garmin or from OSM data.
The routing is done on the active map. I don't know what happens with more then one active maps. I try to avoid that for speed of operation and usage of battery.

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answered 05 Jan '13, 21:20

malenki's gravatar image

accept rate: 6%

Note that older garmin devices can only handle a single gmapsupp.img file, so that only a single map can be installed at a time.

(07 Jan '13, 14:38) Vincent de P... ♦

But it is possible to merge several gmapsupp-files into one gmapsupp.img with e.g. gmaptool.

Though I don't guarantee for nothing. ;)

(07 Jan '13, 14:43) malenki

This does depend on just what maps you are using. All maps in Garmin format have a "draw priority" set, and they may be set as transparent. The map with the highest draw priority will be shown on top. If the map is transparent, then any lower maps will also be visible.

If you are generating maps yourself using Mkgmap, then there is an option to specify the draw priority and set transparency. I don't know if its possible to adjust this on Garmin maps, or pre-compiled OSM maps.

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answered 07 Jan '13, 16:30

Vclaw's gravatar image

accept rate: 22%

I ended up trying this out and found that the Garmin device uses different maps with no apparent rhyme or reason. Basically, it's not a good idea to have 2 active maps when trying to generate a route or view the map.

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answered 01 Sep '14, 00:25

Zian's gravatar image

accept rate: 0%

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question asked: 05 Jan '13, 06:55

question was seen: 6,376 times

last updated: 01 Sep '14, 00:25

NOTICE: is being shutdown on 1st March 2024. Please use the OpenStreetMap Community Forum