How long should ~4gb Basecamp take to build and transfer directly to microSD?

That could certainly take a long while. But there are some limits you should be aware of .

First, Garmin uses the FAT32 filesystem, so you cannot have a file larger than 4gb (the full US topo 100k is ~3gb).

What GPS do you have? The older models have a limit of ~2,000 segments - the individual tiles that make up the whole map. New units (Oregon, Dakota. Montana, GPSMap 62, etrex 20/30) have a limit between 3,000 to 4,000 segments.

If you are trying to send the full US topo, it will not fit on any of Garmin's handhelds. It contains about 6,600 segments. So you can only fit about 1/3 of it on an older device or about 1/2 of it on a new model. If you use Mapsource it will show you how many segments you have selected. I don't believe Basecamp/Mapinstall can do that.

If you exceed the segment limit, some parts of the map will not be usable.

-Boyd

I have a Legend HCx. I ran into the 2025 limit at one point trying to install earlier but it didn't seem to complain this last time around. It is staying under 4 gb (though it shows ~7400 mb remaining in MapInstall when I start adding files. It jumps to none after about 4gb installed).

I had no idea the US 100k topo would be 6600 segments. Coming from an ex-computer programmer, I am really unsure what they were thinking with these limits.

Are you saying MapInstall will allow me to add far too many segments and then it will still try to build it, but it will just fail? I can't even check exactly what I added at the moment as it is 15% (i.e. 2 hours or so) through the build. I Added some 80% of the US topo, leaving out chunks of the non-coastal west, along with OSM routable and some NY layers from GPSfiledepot.

Oh! Wait! I think I understand you. It will build a map with too many segments (perhaps because I am going directly to microSD instead of to GPS?) and will work somewhat but just leave out some data? Is there a way to make sure I am under the appropriate amount of segments?

Thanks for the response!!

edit: Ah. I suspect I ran into the 2025 limit earlier when I erroneously tried to use Basecamp to install directly to the Legend. Now that I am transferring directly to SD I suppose it doesn't know which device I have and therefore doesn't bother to warn me I am going high up in segment number. Meager progress in understanding, huzzah! So will a file with far fewer segments load faster, even if the total size is around the same?

edit2: Since it is likely even if it finished it would not function, I backed out of the build and removed more than half the country frmo the US 100k topo selection. I kept all the other layers. I don't see any way for it to tell me how many segments I have selected, which, again, seems just like shoddy programming and not much else. Does anyone know of a method?

Unfortunately MapInstall for WIndows does not show you how many map segments you have selected. Nor does MapInstall "know" how many segments are supported on a connected Garmin GPS (yes, it should). And, yes, MapInstall will try to build map sets that are over the allowed 3.99GB FAT limit and not tell you until you try to load them onto the device.

Hmmmm, sounds like several Feature Request's.

Cheers,

I had no idea the US 100k topo would be 6600 segments. Coming from an ex-computer programmer, I am really unsure what they were thinking with these limits.

As an ex-computer programmer, you will understand "legacy systems". ;) This is the reason - the old Garmin handheld devices had tiny amounts of memory - as little as 8MB. There are still several products like this in Garmin's lineup. They made the segments small to allow you to pick and choose carefully which areas to install on thse old units (which had no memory card slots).

To deal with this, you need to use Mapsource. It will see the maps you have already installed in Basecamp and will tell you how many segments you have chosen before you send to your GPS. Download here: http://www8.garmin.com/support/download_details.jsp?id=209

I suggest some tricks to optimize process of assembling maps for GPS like your Legend:

First use virtual GPS:
https://forums.garmin.com/showthread.php?p=114522#post114522

Next, send maps to HDD with latest Mapinstall:
http://www8.garmin.com/support/download_details.jsp?id=3291

Mapinstall will create separate file for each of your map. You need to do it only once, unless you update maps.

To assemble maps for GPS use Gmaptool:
http://www.anpo.republika.pl/download.html

Gmaptool allows for selecting files created by Mapinstall and joining them into single file suitable for GPS. You have to copy this file to SD as \Garmin\gmapsupp.img, the fastest way is to use card reader on PC.

Unfortunately MapInstall for WIndows does not show you how many map segments you have selected.

MapInstall 4.0 does show the number of selected tiles on the Advanced Page.

@Boyd / Ostroff. Ahh, that makes some sense. I had figured they would have rewritten the code a few times by now. But leave well enough alone, I suppose. Also, I noticed you have over 10,000 posts on another GPS forum. You are a wonderful asset to these GPS communities -- keep up the good work! Thank you!

@Pope. I hadn't looked into these yet. I'll check them out! They basically simulate the functionality of Basecamp and Mapinstall, but without those programs, correct?

@Falagar. Thank you good sir! You are correct in that the newer version for PC has a segment count! I wonder why my 3.14.x didn't show any updates when I clicked the "check for updates" in the menu. This allowed me to double check and sure enough what I have loaded is around 1650 segments out of the 2025 maximum. No non-working map surprises in the field for me! Hopefully, anyhow. The set of maps I first tried to install was FAR above the 2025 limit.

@Thread topic / general help. I found a microSD to SD card adapter significantly faster than a USB 2.0 card reader.

They basically simulate the functionality of Basecamp and Mapinstall, but without those programs, correct?

Mapinstall is the program which sends maps to GPS. It works nicely for new devices, where it can send each map separately but there is not much help with GPS, which support maps in single file only.

I'm using Mapinstall or Mapsource too, but with some other helper tools. First is vgps, which is configuration setup for Mapinstall and Mapsource. It allows for saving maps in a directory on hard drive. Mapinstall works with vgps as with any new device, creating each map in a separate file. This is convenient, since you don't have to process all maps every time you want modify set of maps in GPS. Mapinstall will update only maps, that has been changed.

Second tool is Gmatool, which is a program for merging multiple maps into single file. Gmaptool can do many other tasks, but merging maps was its primary purpose. It can't fully replace Mapinstall, since it doesn't process map indexes. That's why you need to use Mapinstall to assemble single map file first. If you have these files saved on your hard drive, then selecting and merging is very fast.

And, yes, MapInstall will try to build map sets that are over the allowed 3.99GB FAT limit and not tell you until you try to load them onto the device.

That is impossible (at least for a single .img file); FAT32 isn't the only limiting factor.
.img files are a (sort of) file systems of their own. Inside the file the positions where the device can find the various map elements are indicated with unsigned 32 bit integers. The maximum value for an unsigned 32 bit integer is 2^32 - 1, or 4,294,967,295. This means that it cannot address positions beyond the 4 GB limit...

Actually building images greater than 4GB is possible. There is no direct 32 bit pointers inside img, it has structure like FAT16 disk with clusters and 16bit indexes to clusters. 4GB file uses 64kB cluster size, with 128kB cluster you will get maximum 8GB file. I have tested, that GPS can read files with 128kB cluster.