Garmin Zumo XT Additional Maps On Micro SD Card

Without really knowing I'd guess that you can only have one map capable of routing running at a time. I can imagine conflicts with more than one.

IIRC topo maps don't provide routing so (maybe) one could display at the same time as a road map.

A "dirty little secret" about Garmin devices is something called the "tile limit" (also called the "segment limit" sometimes). This is completely different from the amount of free space on a memory card. It has to do with the individual "tiles" that make up each map. The limit varies per device and is pretty bizarre. Older devices like the GPSMap 60csx could only use about 1000 tiles total (this is the sum of all the tiles in all the maps on both internal memory and the memory card. And it doesn't matter whether the maps are enabled or not, just how many tiles they contain. You would have to actually delete some of those maps if you're over the limit, disabling them isn't enough. Some of the newer, premium (= expensive) units even have a 10,000 tile limit IIRC.

Devices like the Oregon and Montana have a limit of something like 4,000 segments. If you exceed the total number of tiles, some maps won't work or else parts of them won't show. It's impossible to generalize, because it depends on the specific mix of maps on your GPS.

That is very often the reason for problems like you describe. There are no standards for how large a "tile" is either, that is completely up to the map maker. A tile might be a whole state or just one county. In the case of Garmin's own maps, this became a big problem with things like their US Topo 100k which had something like 6000 tiles if you purchased the DVD version, so you couldn't install the whole thing regardless of how much free space you had on an SD card. Their solution for this was to release a special version of the map pre-installed on a card, that was re-compiled to only contain around 1000 tiles (ie: it's the same map, but with fewer tiles that are larger than the old version).

But - here's the thing - this usually only affects Garmin's handheld devices, they have stated that their automotive devices don't have any tile limit! Go figure... makes no sense to me. Now, the Zumo is sort of in between an outdoor and automotive device, so maybe it has a tile limit? You could try some searches for things like "Zumo segment limit" or "Zumo tile limit" and possibly learn something.

Of course, there could be other things going on as well and I am getting pretty far out of the loop when it comes to Garmin. But, for starters, I would want to find out if your device has a tile limit, and if it does, then you need to know how many tiles you are currently using. One tool for that is would JaVaWa's free software, such as device manager

https://www.javawa.nl/jdm_en.html

It is also a good general purpose troubleshooting app for Garmin devices which may identify other problems and even offer to fix them. Again, I don't follow this stuff anymore and there were some notes about compatibility issues with newer versions of Mac/Windows software, so you will have to check that out yourself...

One theory I have is that it might have something to do with the names that are assigned. I know that most websites that discuss this state that maps must be named "gmapsupp.img", but can also have a number before the decimal point. So, "gmapsuppw.img" would be permitted.

I have found out by experience that is inaccurate, however. When I downloaded Open Map Chest maps the first times, would change them to the above format. One time I forgot and it worked fine.

Those names are:

OpenMapChest US Midwest.img

OpenMapChest US Northeast.img

OpenMapChest US South.img

OpenMapChest US West.img

OpenMapChest US Pacific.img

With regard to BBBike maps, I still change them to the "gmapsupp.img" format, but I might experiment with other names. The first BBBike for a give region seems to read fine. For example,

us-midwest.osm.garmin-ontrail-latin1

I will download and install another one from the midwest region and it will have a name like:

us-midwest.osm.garmin-bbbike-latin1

I change both of them to a unique name like "gmapsupp3.img" or "gmapsupp4.img" after downloading them and placing them in the Garmin folder on the micro SD card on the Garmin Zumo XT and only one will be displayed as a map choice on the device even though Garmin Base Camp shows both of them.

A little bit ago I decided to use the extract service on BBBike and that map has a different name and the Garmin Zumo XT seems to work with that just fine!

You need to visit some newer websites! That used to be true, but it was long ago. Garmin did away with that system many years ago, starting with the Nuvi series and then extending into their outdoor devices. I think your Zumo is a fairly recent model, isn't it? If so, then it most certainly will not have that limitation. Just offhand, I'd say any Garmin device made after circa 2008 will not have tha map name limit.

One thing they did change with some newer automotive devices is that when you add 3rd party maps, they need to be put in a folder named Map in the root directory and NOT in the Garmin folder. You should look at your device's manual, or try a search to confirm that. My experience was, that on some of these newer automotive devices, 3rd party maps would work in either the Garmin or Map folder while on others, the maps would only be recognized if they were in a folder named Map.

Regardless, I doubt that is your problem. Maps also have an internal ID number that is used to tell them apart. If two maps have the same ID, that will be a problem. Again, try that program I linked to, it should be able to help with issues like these.

Thank you for the reply. The Garmin Zumo XT came out in 2020.

I did just move the additional maps from the Garmin folder to a Map folder. The link below verifies what you suggested.

https://support.garmin.com/en-US/?faq=21G3VnXffc3fvlt4Ru9Yg7...

I have used the website below in the past and I will look a bit closer at it, again.

https://www.javawa.nl/jdm_en.html

I was able to add additional BBBike maps by using the extract service. Premade regions are certainly more convenient and quicker, but that isn't the end of the world, either.

Selecting my own region is limited to 512MB file size. Some of the premade regions are bigger. For example, here in the Midwest, both the Garmin Openfietsmap Lite (Latin1) and Garmin OpenTopoMap (Latin1) 1.3GB!

https://extract.bbbike.org

https://data.bbbike.org/osm/region/north-america

I have spent enough time on maps the past couple of days, though. I will say that even though I have had the Garmin Zumo XT for a few years, I am still learning more about it.

I will probably continue to time my future Open Map Chest and BBBike updates with the Garmin City Navigator map updates. If I am connecting my Garmin to a computer for City Navigator update anyway, I might just as well update Open Map Chest and BBBike maps at the same time!

I believe the older nuvi's (specifically 2xx, 5xx, 7xx and 8xx series) never did incorporate the new map naming rules and still have the restrictive naming conventions. When first released, only gmapprom, gmapoem and gmapsupp were recognized other than the special purpose maps (such as gmapbmap, gmaptz, gmapdem, gmap3d). An additional restriction was that gmapprom could not reside on the SD card.

When Garmin started preparing for map files exceeding 4 GB that needed to be delivered as two files, they added support for one additional name (gmapsup1) via a firmware update (version 4.40 released in 2012 for my nuvi 755T).

Probably not too many of these old nuvi models are still in use, but it is interesting that the newest maps still install and work on my old nuvi 755T. I don't use it anymore but install the maps on it just out of curiosity. The 7x5 nuvi's are one of the few where Garmin is still providing the full screen JCV junction view files with the map update, and those files remain popular downloads for some members of this forum.

I think my recollection is actually pretty good - and I even changed google's mind, LOL. But you might be right about the Nuvi model numbers when the transition took place. 2008 still seems like a long time ago in my book though! I did a simple search for "garmin n-map device" and Google AI said:

"The term "n-map" is likely a slight typo for on-device mapping, a non-sonar chartplotter (like the marine Garmin GPSMAP 1223), or a navigation map device. "

I responded:

"I don't think this is a typo. I believe "n-map device" is a technical term used by garmin to refer to a generation of devices that have more relaxed map naming conventions than their legacy devices.

Older garmin devices only recognized very specific names for maps that were not pre-installed on the gps, they had to be named "gmapsupp.img", then there were things like "gmapsupp1.img" and so forth.

But at some time, they started recognizing almost any valid alphanumeric map name. IIRC, the key to this was found in a special file on the device in internal memory named garmindevice.xml (or similar). I may have some details wrong, but think the basic pattern is correct. When did Garmin begin recognizing other map file names? I think it was sometime after they began using usb mass storage to connect to their devices instead of their proprietary serial format..."

Google AI responded:

"You are entirely correct, and your technical memory is spot on. The term NMaps (short for New Maps or Named Maps) is the precise XML flag used inside the GarminDevice.xml file that defines this transition.

Garmin began introducing this capability around 2008 to 2009, aligning with the release of the nüvi 1xxx series and outdoor handhelds like the Oregon, Dakota, and Colorado series.

The NMaps Architecture Break
As you recalled, the transition happened right as Garmin shifted heavily into the USB Mass Storage era.

* Legacy Behavior: Older devices explicitly looked for a tag in their XML, hard-coded only to recognize gmapsupp.img (and occasionally gmapsurv.img or gmapsup1.img on an SD card).

* The Modern Solution: Newer firmwares added the NMaps schema inside GarminDevice.xml. This container told software like Garmin MapInstall that it could transfer and read any custom alphanumeric string (e.g., Colorado_Topo.img or MyCustomOSM.img), provided it retained the .img extension."

FWIW, I just looked at the GarminDevice.xml file on my old Nuvi 205. It still has the gmapsupp.img restriction. You could check your own devices like this (if you even care, which most people probably don't, LOL)

|File||Specification||Identifier|IMG|/Identifier||/Specification
|Location||Path|Garmin|/Path||BaseName|gmapsupp|/BaseName|
|FileExtension|img|/FileExtension||/Location|
|TransferDirection|InputOutput|/TransferDirection|/File|

(note: I had to replace the xml tag delimiters with vertical bars and also split it across several lines, because the forum software got confused!)

Of course, it gets even more complicated. IMG files are actually "containers" that can hold many maps, depending on how they are created. Mapsource (and Basecamp, when you use it with one of these old devices) can bundle up all the maps you want and put them into a single gmapsupp.img file. This was their (clever, but pretty kludgy) solution to installing multiple maps. It confused most people though, because doing this with Mapsource was far from intuitive.

Basically, you had to select all the tiles you wanted from all the different maps on your computer FIRST. Then you would send the whole thing to the GPS. But most people would just select a map, then send it to the GPS. Then when they selected another map and sent it, the first map they sent would be erased, leaving only the last one that was sent!

Ah, the good old days!

Not too many of us remember that map updates used to be something you had to pay for, at first for each update. The lifetime map subscription was introduced in 2008. I purchased it for my nuvi 755T as soon as it was offered for a price of $129.95 as I recall. Garmin started bundling the lifetime subscription with new models shortly thereafter, but those of us with older models had to pay.

Well, this does bring back memories. My first experience with a Garmin was when my neighbor that lives next door was raving about his Garmin StreetPilot. It might have been a 2610 or 2620. He offered to let me borrow it for one week. I was out in the car for work pretty much all day, so I gave it a great workout. I brought it back to him after the one week and he said it use it for one for week and I did.

I made up my mind that I wanted one of my own and I set my sights on a Garmin StreetPilot 2730, However, they were so expensive that I bought one used for a private party. I liked the XM Satellite radio feature, too, of course.

I don't recall how current the mapping software was when I purchased it, but at some point I decided to splurge for an update. I received either a CD or DVD in the mail from Garmin and updated the maps.

I had a StreetPilot 2620 and just loved that thing. On a cold morning, you had to wait while the internal heater warmed up the microdrive to operating temperature! But the best thing was the remote control - like a tv remote. You could control the streetpilot like it was a push-button GPS, without having to reach up on the dashboard!

I put the United States Open Map Chest maps on my Garmin DriveSmart 65 with Amazon Alexa tonight. All five regions, Midwest, Northeast, Pacific, South and West seem fine.

I then tried the Garmin BBBike (Latin1) maps. I was able to rename South and West and the Garmin displayed them fine. However, when I added the Midwest region, the Garmin would give that map as a choice. I showed up on Garmin BaseCamp. When I deleted the Garmin BBBike South and West maps, Garmin BBBike Midwest was a choice, again.

For some reason certain BBBike maps seem to have some sort of conflict with one another. I will email the team at www.bbbike.org and see if they have any insight on this.

The app I suggested before was made specifically to troubleshoot this kind of problem. I always considered this, and his other program (GMTK) essential tools for anyone who uses Garmin GPS units (although I am quite happy to no longer be in that camp today, LOL)

https://www.javawa.nl/jdm_en.html

Only caveat is, the author has not updated it for awhile, so you will have to see if it still works for you