.img files?

[Mike Cook]

I'm confused re.

gmapbmap.img
gmapprom.img
gmapsupp.img

gmapprom is the default mapset (ie, for your home country)?

gmapbmap is "base map"? Surely this isn't a complete detailed map: the file size is only 15 percent of the other .img files. Why so small? What is a "base map" and how does it differ from a mapset?

gmapsupp is secondary mapset? If, for example, you want to visit another country you can load a map onto an SD card and name it gmapsupp.img?

Which of these are required; which are optional?

Is my understanding correct?

Tx.

 

[ps56k]

here's a re-post of mine - from Jan 2010

BTW - You might indicate what GPS you have,
and what maps are listed in your "About" screen.

---
After a recent map update to my Garmin Nuvi 255 GPS,
I looked at the GPS sub-dir to see how big the map image file was...

In looking around the GPS sub-dir,
I noticed a couple of other different files....
These appear to be the new TimeZone files -

SO - this is my D:\Garmin sub-dir of map info

gmaptz.img Time Zone map info
gmaptz.sum

gmapbmap.img 92mb - basemap
gmapbmap.sum

gmapprom.img 1.1gb - latest CNNT 2010.30
gmapprom.unl guessing map unlock code
gmapprom.sum

gmapsupp.img 19mb - my topo map segments

 

[Mike Cook]

Garmin Nuvi 660

 

[Mike Cook]

So, which are required and why?

And why is a "basemap" only 92mb and the primary mapset is 10x that? What's in each? Are both needed?

Thanks.

==

 

[ps56k]

So, which are required and why?

And why is a "basemap" only 92mb and the primary mapset is 10x that? What's in each? Are both needed?

Thanks.

Well - you can pretty much delete what you want,
and then you'll have no maps - and a pretty useless GPS

Why are you asking about deleting things ?
Are you looking to delete to save space or what ?

You replied that you have a Garmin 660 -
BUT - What "maps" do you have installed ?
We have no idea what products you have purchased
or installed on your GPS - and each will create a file, or a set of files...

Basemap - very basic map image with nothing else
Purchased maps - add more map details and POIs for reference/lookup.

 

[Mike Cook]

What's the purpose of a basemap? You can't select a it. Is it only defaulted to if no purchased mapset is installed? Does it become optional if a gmapprom or gmapsupp file is installed? Can this be deleted if a purchased mapset is installed?

I don't like files sitting around (on my computer or GPS) that aren't needed. And this leaves more room for MP3's, audio books, POI's, etc.

Installed: NA mapset including USA & Canada

Planning on getting Europe too.

 

[Robert Schiele]

What's the purpose of a basemap? You can't select a it. Is it only

It is a world map with only continental coast lines and major metropolitan areas marked as single points. There are variations on some models where the basemap also includes more cities and major roads of the continent you purchased the GPS. For instance if you purchased the the GPS in the US or Canada major roads of North America are included and other continents are more limited and if you purchased a model for Europe there are some more details for Europe but other continents like North America are very limited.

Technically you don't need the basemap and for regions where you have any other map coverage it is more or less useless. If you look at an area where you do not have map coverage it will provide some information about where you are while when you delete it you won't even see whether you are on the ocean or on within a country.

Considering this example that you have:

Installed: NA mapset including USA & Canada

If you travel to Europe without buying additional maps you would still see cities like Paris or London from the basemap. If you deleted the basemap you wouldn't even see that there is a continent at all.

Robert

 

[Mike Cook]

It is a world map with only continental coast lines and major metropolitan areas marked as single points.

[...]
Robert

Thank you Robert. That fine, thorough explanation is exactly what I was looking for.

You'd make a good writer.

Another Q: is there an editor for separating mapsets? If a purchased mapset which includes USA & Mexico, and I already have a map of USA, how do I edit the USA / Mexico set so as to delete USA (I don't need 2)?

(FYI, I'm using OS X.)

Thanks again.

 

[Holger Issle]

Hi Robert,

Technically you don't need the basemap and for regions where you have any other map coverage it is more or less useless.

Be careful - the GPS uses this mapset at a resolution of (depending on details settings) 12km to draw the display, and no longer the purchased mapset. I believe this is for speed resaons.

So, there is a need for the file to be there.

 

[Mike Cook]

Be careful - the GPS uses this mapset at a resolution of (depending on

details settings) 12km to draw the display, and no longer the purchased mapset. I believe this is for speed resaons.

So, there is a need for the file to be there.

Thank you Holger.

"The plot thickens" .

So no matter how many brand new map sets I have installed, the Garmin needs the gmapbmap file?

 

[Sunshine]

Thank you Holger.

"The plot thickens" .

So no matter how many brand new map sets I have installed, the Garmin needs the gmapbmap file?

Rename the file. If you discover that you need it, rename it back to original.

 

[Holger Issle]

So no matter how many brand new map sets I have installed, the Garmin needs the gmapbmap file?

In my experience it makes use of it. Map drawing is much quicker if the basemap is present at a specific scale of display, and there will be no more map display if the basemap is missing, at an even bigger scale. Exact numbers depend on your model and detail settings, so try it. The basemap assists as well in some searches.

 

[pete]

What's the purpose of a basemap? You can't select a it. Is it only defaulted to if no purchased mapset is installed? Does it become optional if a gmapprom or gmapsupp file is installed? Can this be deleted if a purchased mapset is installed?

I don't like files sitting around (on my computer or GPS) that aren't needed. And this leaves more room for MP3's, audio books, POI's, etc.

If it is lack of space that is the worry why not install an additional card. I installed a 8GB card in my 660, it gives ample room for all the MP3 etc I'm ever likely to need.

Pete.