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How Do I Load Maps On My GPS Unit?

Started by -Oz-, February 04, 2010, 09:11:43 PM

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Not sure why you're having this problem.  An Etrex20 isn't a cheap unit.  I own an Etrex30.  The only difference between the 20 and 30 I'm aware of is the compass and altimeter.  To test out your gmapsupp.img theory, I sent -Oz-'s Arizona Topo to the card on my E30.  I've now got two IMG files in the Garmin folder on the card.  They are named Arizona Topo.img and DesertSouthwest.img.  They are the only maps on the GPSr, except the basemap, and they are both selectable from the "Select Maps" page of the Setup Map dialog.

Just curious: the Topo East, Topo East 2, Topo West, and Topo West 2.  Where'd you get them?


I originally had an old eTrex Legend that camp with those rudimentary topos.  Come to think of it.  There were 4 of them (East, West, Alaska, and Hawaii), but I don't see either Alaska or Hawaii in the list, even though MapInstall shows them as being on my eTrex 20.

I just put a new, formatted MicroSD card in my 20 and, from BaseCamp, I right clicked the SD card and did an Install Maps on SD Card, which brought up Garmin's MapInstall.  It successfully downloaded the motop11.img file to the SD card (in the Garmin directory).  Then I did an Eject on the GPSr, restarted it, and sure 'nuff - NO mention of anything but those old topos I brought over from the Legend in the Map Setup.

I haven't done it yet, but I'll bet that if I rename the motopo11.img file on the SD card to gmapsupp.img, then the Missouri topo will show up (with the odd name).


Unless you tell it otherwise, Garmin's software will use some of theselected quad/tile/segment names to identify the mapset; in this case 'Dyersburg (w), Sikeston, Cape Girardeau'.

Those 'old' Garmin topos might be causing a problem.  Try changing the .img extension to something other than .img.


...  Edited: The following may be related to having old eTrex Legend topo maps on an eTrex 20, which was causing multiple issues.

I don't know if it is related, but there have been times when I've downloaded 32 geocaches, but only 17 of them showed up on the unit.  I remember deliberately driving to a different location to see if it was only showing the nearest 17 of the 32, but it still didn't show the closest GCs.  I plugged the unit back in and BaseCamp showed that there were 32 GCs on the eTrex 20.  But try as one might, the unit itself would not show all 32.

Ever since then, I've only ever downloaded about 16 GCs at a time.  I'm always envious when I hear other folks talk about downloading a Pocket Query full of GCs - like 200 - to go geocaching.  My eTrex 20 could never do that.  It'd show 200 of them on the unit when plugged into BaseCamp, but no where near that many on the unit alone.


The AK & HI no show issue should be taken to Garmin's tech support as it involves their mapsets on their GPSr. 
It may have something to do with transferring those files from your older Legend.  Do you have Garmin source CD's for those maps?

Garmin does not recognize independent map authors and will not talk to you about the MO topo mapset.

As Seldom mentioned, the ability to recognize other user map file names than gmapsupp.img
has nothing to do with Etrex20 versus Etrex30.  It began with the Colorado models and all since than have that capability.

If those older topo files are not causing the issue, perhaps you have a defective unit.
Do you have the latest firmware/software for the Etrex20?

Doesn't MapInstall allow you to select from additional mapsets before sending to the GPSr?


FYI, you were probably right the first time.  There is some bad aura about those original eTrex Legend topos.  I finally ignored them and downloaded 6 topos of states that I'm interested in (for now) from this wonderful site, and the eTrex 20 was able to display all 6 of them in the Setup Map --> Select Map page.  Since I'm a little skeptical, I'll probably download a 7th map and see what happens.

Thanks for all of your help.  Keep up the good work.


Just wanted to say that I think this site is absolutely wonderful!  You have been extremely helpful.  And of course, the value of the maps is priceless.   Keep up the excellent work.

BTW, for other folks affected, the old eTrex Legend topos do cause troubles with an eTrex 20 (and perhaps others).  Since I took them off my GPSr, the unit comes up faster and responds to requests (such as zoom in and zoom out, etc.) faster.

To avoid issues with Garmin's MapInstall program deleting existing maps before re-installing old and install new maps, here is what I do:

  • At a command line I change directory (cd) to the drive on my unit (or MicroSD card, as the case may be).
  • Change directory to the Garmin directory.
  • If this is a DOS prompt command line session, then I do the following:
    ren *.img *.old
    If this is a Linux, UNIX, or cygwin prompt, I would do this:
    for FILE in *.img
    do mv "$FILE" "${FILE%.img}.old"

    This prevents MapInstall from pre-deleting the installed maps, because it cannot "see" them.  (Don't forget to use the double quotes on the shell lines as shown above, in case files have a space in their name!)
  • From MapInstall's Customize window, I uncheck all the maps that are already installed (and currently renamed).  This will prevent it from re-installing maps that are already there (but renamed).  Just check the new maps that need to be installed.
  • After the install has completed, do the following on the command line:
    From a DOS prompt (in the drive's Garmin directory):
    ren *.old *.img
    Or on Linux, UNIX or cygwin:
    for FILE in *.old
    do mv "$FILE" "${FILE%.old}.img"

    To "unhide" the previously installed maps.
(You may want to copy/paste those UNIX shell commands into shell scripts located somewhere in your command PATH to avoid a lot of typing.)
This is a bit of a pain, but it saves gobs of time when installing new maps.  I have been doing this several times now and it works great.

Of course, if you download all the maps you want/need and install them en masse it'll also save effort, because you don't have to keep doing the above for each set.  ;)


Quote from: MountainWoods on May 07, 2013, 08:33:25 AMBTW, for other folks affected, the old eTrex Legend topos do cause troubles with an eTrex 20 (and perhaps others).  Since I took them off my GPSr, the unit comes up faster and responds to requests (such as zoom in and zoom out, etc.) faster.

Glad you got everything working. I understand why startup is faster, but I don't understand the part about zooming faster. I think the only way the old topo could affect map redraw speed would be if you had it enabled along with another map. It might be the case that these maps automatically became grouped with another map and therefore enabled however.

There's another issue to keep in mind. On my Montana and Oregon, whenever I did a firmware update, the next time I started the GPS up every map became enabled in every profile. This is a real nuisance, because you have to manually go into each profile and disable the maps you don't want. If a bunch of maps covering the same area are enabled, the GPS will respond very slowly.

I actually have a theory about your map install problems, knowing that you have been using the old topo maps. Garmin's old 100k topo is built with very small tiles since devices with tiny amounts of memory were common then. IIRC, the whole US has about 6600 segments. But your eTrex (and all recent handhelds) can only access 4000 map segments. So if you installed a large part of that old topo, you may have passed the segment limit.

When you go beyond the segment limit, you will get the exact behavior you described - some maps or portions of some maps will not work. Garmin says it is hard to predict what will go wrong when you have too many segments because it depends on exactly what is loaded on your GPS.

You could check how many segments you have installed in Mapsource using the map tool. The total should appear in the left window pane. You have to be sure to stay below 4000 total. This has nothing to do with the size of a memory card - the 100k topo is only about 3gb.


Boy, I haven't used MapSource in a year.  I didn't realize that the maps I'd downloaded from GPSFileDepot would also show in there, but it makes sense in hindsight!

Sure enough, from the old Legend topos, just the eastern US contains 2563 sections -- which were split in half as US Topo - East and US Topo - East 2 when I went to BaseCamp.   Here's what I was trying to stuff into the eTrex 20 (without realizing it):
2563 segments Eastern US (2 map files)
2662 segments Western US (2 map files)
1425 segments Alaska (1 map file)
0027 segments Hawaii (1 map file)
6677 segments Total

I'm willing to bet that that analysis is 100% the problem.  It would explain why it seemed eratic as to which maps were showing or not, such as the fact that Alaska & Hawaii weren't showing even though all 6 map files were in the unit.  Even my trick of renaming the files may have just caused the unit to load the maps in a different order, finally picking up motopo11 before trying to load those old maps; and thus having it "work" partially - just missing some of the old Legend topo maps.  Makes complete sense to me.

Odd thing is, I remember when I got the eTrex 20 I called Garmin support near KC and asked them if I could just reuse the maps from the old Legend and they said it was fine.  Ha!  It's odd that they didn't tell me about the max 4000 segments.  I imagine that I could run into the same problem with maps from this site if I get too greedy, unless the segment sizes are very, very large compared to those old topos.  Guess I can check those in MapSource too.

Well, as an IT Architect, I often have to deal with folks who complain about programs being too slow; so I understand the importance of perceived versus actual performance.  I may have been wrong about the zoom in/zoom out performance increase.  But I can definitely state that starting up the unit doesn't take as long.  And no wonder!

Thanks again.  I'm glad that you knew about the internal limitations of the firmware.  Cleared a lot of mystery.


Answered my own question.  Went into MapSource and selected all of the segments on all of the maps I had downloaded so far from this site, and it was less than 2000 segments.  Cool.

I wonder if MapInstall tells you how many segments you're about to download.  I'm not in a position to use it just now.  Anyway, 'twould be nice if it told you that.  'Twould even be better if it queried the unit for its maximum capacity (or looked it up in a table) and let you know if you're going overboard.

I can understand why the old topos had such a high number of very small segments.  An annoying problem with the old Legend is when I'd be getting ready for an outing and I'd be pulling my hair wondering if I should select that segment or this one over here.  Where am I going to wonder into?  How can I fit this all in 8 Meg?  If the segment sizes would have been large, it would have made the decision really bad!

As overall maps, I really liked those old topos, even though they aren't detailed.  It was nice that they covered half of the country, instead of 1 state at a time.  But they'd have to be combined somehow to be usable any more.  And I doubt that Garmin's going to do that gratis!  And no one else can, because the maps are theirs.  Oh well.  I can still view them in BaseCamp.


Glad I could help. :) Actually Garmin released a special version of the 100k topo when the first device with a pre-loaded map appeared (Colorado 400t IIRC). That version only has about 450 segments for the whole US, and you can purchase it now either on pre-loaded card or via download.

I have read that there's a new version of the 100k topo which is shipping on the Oregon 6x0 series, possibly using Navteq road data, like the 24k maps.


'...just reuse the maps from the old Legend and they said it was fine.' 
1.  Garmin might have been thinking of the legal side of reusing the maps.  Some of their products are licensed to a single GPSr or micro memory card.
2.  I would take 'from the old Legend' to mean the files you had on the Legend.  With the multi Gbyte capability of the newer GPSrs, 8Mb would be 'fine'.  Did you inform them you loaded the entire topo mapset (West, East, AK & HI)?

Garmin is known to have erroneous specs.  The actual segment limit for some of the newer units are in the mid-3800's.  There were some posts on that 2-3 years ago on other websites.
There were about 3975 segments for the 48 states in topo11.  When I sent the last 'block' of files to the OR300, I got a message about too many segments. The OR300 did start, however, some of the segments in the last 'block' would not display.   After renaming the first 'block' with a non-img extension, the 'missing' files displayed.  I changed the extension on the first 'block' and created a small last 'block' along a line of longitude;  total segments were about 3840 and all displayed.  I added .img files a column of longitude at a time to the last 'block' and never received an error message; even when the total segments on the GPSr was back to 3975; however, when I did a visual on the GPSr, some of the segments did not display.  As your experience also indicates, the GPSr's segment limit may be exceeded  and an error message may or may not be given.   

In some respects BaseCamp and MapInstall are not a informative as MapSource.  Garmin created them for their Birdseye raster files and only gave minimal support to vector files.
The newer units also have some types of files (POI's and waypoints) in a different location so MS will not be able to move them. 

It is a trade-off in have recent data available for the perfectly good older units versus maps that take advantage of the capabilities of the new units.  I have been slowly increasing the average file size of my mapsets.  A few years ago, a mariner asked if some segments in OZ's FL topo could be made smaller as his Garmin marine GPSr unit had a total memory of 1.2Mb.
Last fall I received an e-mail from a user whose GPSr only had 800k of memory.

I have never tested the performance of a mapset with 200 1Mb .img files versus the same area in 10 20Mb .img files.  I think Garmin's topo100 mapset had 60+Mb .img file sizes.   I had some test mapsets in the 6 - 8 Gb range and GPSr startup times were about 10 seconds per Gb; and a few times in less than 15 seconds total.  Who knows why. 


   Have you heard anything of an update of the 24k topos?  This winter, Garmin's specs were still saying v2.0, 2009.  When I check last week there was no info on version nor date.

USGS did not finish replacing the very poor NED data created by photomapper and manual profiling production methods until the Dec, 2012 'release', and the remaining oversampled NED data until the Feb, 2013 'release'. 


The maps I got with my Legend were on a DVD back in 2005.  I remember that it was annoying that they did not have a way to copy the data files to the hard drive (like DeLorme's Street Atlas has always had).  They expected MapSource to read the data from the DVD every time it was used.  Yuck!

But, again, being computer savvy, I copied the data files onto my HD, used regedit to find where MapSource was looking for its data (e:\ I think), and changed it to point to the directory on the HD -- crossing my fingers that the longer directory name wouldn't cause an internal filename buffer overrun -- and it worked.  I did the same thing when I later upgraded to this PC I'm on.

(Even more annoying: the Walmart salesman lied to me and said that the Legend could plug into a USB port.  I was flabbergasted when I got home and found that it needed a serial port; at a time when serial ports were already archaic.  I hadn't had a PC with a serial port for years.  I had to purchase a serial to USB converter to use the blasted Legend.  I figured that the Legend was already supposed to be just a legend.)

Last year I installed BaseCamp whilst I still had the old Legend, and BaseCamp recognized the data files also.  I remember talking to Garmin very early on, perhaps before I even bought the 20 or just after, can't remember which.  I asked them if I could reuse the maps I had with the Legend.  I doubt that I told them that I was planning to install all of the files on the unit at the same time (since it didn't occur to me that that might break a limit).  Anyway, like you say, they may have been thinking about permissions to reuse the same maps, rather than capabilities.

Still, it's funny that they didn't tell me that not all of the segments would fit on the 20 (inspite of the files themselves fitting).  I knew that there were many segments in a given file, but I never new what the limit was or, indeed, if there even was a limit.  Boyd's explanation was the first time the light bulbs started lighting up.  "Of course.  Too many segments!"

When I plugged in the eTrex 20 for the first time and brought up BaseCamp, it seems (if I remember right) that it "noticed" that the unit only had the base map and that I had more data files present, so it asked me if I wanted to install them.  Gleefully and naively I figured "Why not?"  Without having had a technical discussion on segments and the limits of the unit, who would have done otherwise?  Seemed great to me!  Live and Learn.

Now I realize that I should have used the Customize to copy just areas of the country that I was interested in at the time.  But even then, neither MapInstall nor the unit warns you that you've got too many segments being copied over.  Duh!


Quote from: maps4gps on May 07, 2013, 06:28:13 PMIn some respects BaseCamp and MapInstall are not a informative as MapSource.  Garmin created them for their Birdseye raster files and only gave minimal support to vector files.

Are you sure about that? Basecamp was introduced in January 2009:

Quote"BaseCamp brings a whole new set of features to hikers, hunters, geocachers, and anyone else who wants to maximize their experience with their Garmin GPS," said Dan Bartel, Garmin's vice president of worldwide sales.  "This new utility lets users view, organize, and transfer their data more quickly and efficiently – allowing them to make the most of their time exploring the great outdoors."

Birdseye didn't come along until January 2010:

FWIW, "Custom maps" (.kmz files) were introduced in October 2009