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June 2013
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Upgrading to a Garmin Oregon GPS–Yes, Do It

91c3zV4wtZS._SL1500_So, I finally broke down and got a Garmin Oregon 450.  This is not a review.  There are lots of reviews out there, anyway, and you can find all the details about the unit on the Garmin site.  Instead, my point here is just to mention its usefulness in the Bolivian context (or that of any other out of the way, difficult to map, place), which, in my view, is where the Oregon shines, and perhaps to help people get the most of the unit if they buy it.

I’ve had a Garmin eTrex Vista HCx for some years now, and I swear by it.  It’s a great unit.  It’s shown me the way, or at least tracked my paths, across much of Kyrgyzstan and wide swaths of the USA, Ecuador, Kazakhstan, Uzbekistan, and even Bolivia.  Maps are always the problem in these places (well, except for the good old US of A), but Open Street Map and various extensions from OSM have filled the gap handily, if not by any means completely.

The Oregon 450 has a much larger and nicer touch screen, is much easier to use, has all kinds of gimmicks and facilities (like 3-D view and customizable profiles), but the real reason for moving to the Oregon 450 (or one of its brother units) is the ability to install custom maps on it.

The custom maps feature means that you can put any map you can get a scan of onto your GPS (with some limitations, more on that below).  In Bolivia, where the Instituto Geographico Militar has put its whole collection online, that is a real bonanza.  And the facility works well, with the following caveats:

1.  The size limits are pretty restrictive.  Only jpg files are accepted (no progressive scan), they must be smaller than 3 mb, and images over 1 megapixel (1024×1024 pixels, 512×2048 pixels, etc.) render at a degraded resolution.  The maximum resolution is 155 dpi.  In practical terms, that seem to mean that I can get about 1/32 of a Bolivian 50k topo map on a single jpg tile.  That is something under 5×5 km.  Not very useful for driving on the roads, but not so bad for hiking or treking.

2.  The workaround, is that up to 100 custom maps can reside on your Oregon (500 on some premium units), so, with a fair amount of work (more on that below) you could cover, what, 500x500k?  That’s respectable!  An unlimited number of files can reside in one “kmz file envelope (up to the limit of 100, I suppose).”

3.  The learning curve for getting this done is not undemanding.  The process for going from a 5x5km cuadrangle of an IGM .pdf 50k topo map is as follows (with software recommendations, where necessary):

a.  Download your map from the IGM site.

b.  Convert the file to a .jpg.  There are dozens of converters available online.  The one I use, PDF Converter v1.26, is very simple, but I’m afraid it may not be available any longer.  It’s publisher is now offering the ImagePrinter Free, which seems like it might do the job, as well.  If you are going to do this with a lot of maps, it might be worth getting something with batch capabilities.

c.  Cut the file down to the right size and convert to the right dpi (155).  I use Adobe Lightroom 4 for this, since I have Lightroom on my computer for my photography anyway.  It does the job very well.  That said, there are probably better applications for this purpose.  You want to take some care here.  The next step will be geo-referencing the image in Google Earth.  Though that always involves some adjustment, regardless of how you start, it will be significantly easier if you start from an easy to recognize set of geo-coordinates.  For that reason, I try to crop the maps on well defined latitude and longitude coordinates.  The UTM coordinates are marked better on the Bolivian maps, but they are complicated to convert and only partially supported in Google Earth, so using them is much more difficult.

d.  The rest of the job is done in Google Earth.  Find the approximate location where your map goes, and click add/image overlay.  In the dialogue box that opens, put a name for the map, and then link to your map jpg.  Use the “location” tab to input the lat/lon of the edges of your jpg.  Fiddle with the transparency slider to see how the map lines up with the satellite imagery below.  This is a major disappointment.  I have no idea why (somebody tell me!) but the maps are NEVER actually lined up.  In fact, all geographic locations are always too the north, on the map, of where they show up in Google Earth.  As far as I can tell using the GPS, Google Earth is right, and not the map, so move the overlaid map around until the lakes and roads match.  Once you have the overlaid jpg file where it belongs, go to the altitude tab.  Change the Draw Order, which defaults to 0.  To get it to draw on top of the base map on the unit, the draw order should be more than 50.  Finally, hit Ok to save your work.

e.  You’re almost there.  The map has been saved in the “Places” list on the left.  You can put multiple maps into a folder in that list, and then right-click on anything to “save place as.”  Browse to your connected GPS and save the resultant kmz file to the Custom Maps directory (under the Garmin directory).  When you turn your GPS on again, if you did everything right, your new custom maps will be available.

An area near Zongo that I am planning to explore, with the map loaded into Google and ready to upload to the GPS.

An area near Zongo that I am planning to explore, with the maps loaded into Google and ready to upload to the GPS.

Another Hint

Custom maps are great, but they are a lot of work.  You can improve your Garmin GPS experience in places without top flight (and expensive) Garmin maps by going to  Here you can get excellent, routable maps, based on Open Street Map, AND altitude contour lines courtesy of NASA/JPL-Caltech.  And we all know that altitude is crucial in Bolivia.

Have fun.

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