The Garmin Etrex 10 is an entry level hand-held GPS receiver with limited features, however with a bit of extra work it can be pretty bloody good for Geocaching (the notes here are possibly useful for other purposes too). While the unit has limited storage available, and doesn't officially support custom or even detailed mapping, it is possible to load your own maps (detailed maps will only cover smallish areas however).
For all it's limitations, the Garmin Etrex 10 is really suitable for new cachers / recreational GPS users looking to get their first device. Aside from the very basic features you'd expect in an entry level hiking GPS, it has built-in support for Geocaching, it's relatively cheap (as of 2020 it's less than 1/2 the price of the Etrex 20), it's small + light, it's probably a bit better than your phone GPS outside of urban areas, and you can load custom maps with a bit of effort.
I find that I need to update my maps maybe once per year or so, and this gist is available mainly so that I don't have to reinvent the wheel every time I want to play with my GPS. If you happen to get value out of it, then that's nifty too.
- Garmin Express - Basic device updating / data management.
- Geocaching.com - Supports exporting a list of caches direct to your device.
- extract.bbbike.org - Great tool that lets you export maps covering an area in Garmin format
- GPSMapEdit - Shareware tool for editing GPS maps. A little clunky but very useful.
- MapTK - Toolkit for converting map files used by GPSMapEdit
Garmin has an article about some limitations here, however it's not entirely accurate. Here's what I think the main limitations are:
- Small, monochrome LCD display
- Total 8MB storage space available (this is the big one)
- Doesn't officially support custom mapping
- Install Garmin Express
- Connect Etrex 10 to USB
- Visit Geocaching.com
- Open one of your lists, or click on a cache on the map view
- Click Send to Garmin
- Follow the prompts / allow your browser to open Garmin Express
- Open the main menu
- Select Where To?
- Select Geocaches
- Geocaches will be sorted by proximity to you. Select one to see it on a map
- Select Go
- Open the main menu
- Select Where To?
- Select Coordinates
- Input your coordinates and select done
The built-in map on the Etrex 10 is an absolute pox. Install custom mapping because it's not very hard, and you deserve it.
Important: With a total of 8MB storage on the device, your map size is going to be limited to a max of around 6 - 7mb. Keep an eye on your file sizes!
Turn on your GPS and go setup > system > USB moved and make sure it's set to Mass Storage
Plug your GPS into your PC via USB and copy all of the files off it.
Garmin sells mapping for a variety of purposes, but I'm pretty sure that a) it's comparitively shitty compared to the free options (feel free to prove me wrong on this), b) is a bit expensive for what it is, and c) the Etrex 10 is officially a non-mapping GPS unit so your purchased maps might not work.
You don't have as much control over your output map with this, but it's really quick and easy to use especially if you're just putting together a quick map of a small area for a day trip. Unless you're planning on moving around an wider area or going somewhere on an extended holiday with limited access to a computer / internet this is probably good enough for your needs.
Massive props to BBBike for building this, and OpenStreetMap for the data, both are really awesome.
- Visit extract.bbbike.org
- Zoom right out to globe level, then start zooming in on the area you're interested in.
- In my experience with the type of mapping output by this site you'll probably be able to fit an area of maybe 20km square onto your Etrex, maybe more or less depending on how dense your area is.
- When you have the area in mind on-screen follow the prompt "...click here to create the bounding box"
- I didn't find the resize or drag polygon tool useful because it maintains aspect ratio. Click the "add points to polygon" tool
- Click the large rectangle overlaid on your map. Click and drag the circles in the corners to adjust the position of points in your shape, and click the circle in the center of each side to add a new point. Cover the area you're after.
- Near the field to name your area, you'll see an estimate of the size of the output map. I find that this is grossly underestimating size, and the max I was able to get for my area (based on the estimate) was about 2 MB estimated.
- When you've got your shape, pick your format. Any of the Garmin formats should work I find the OpenTopoMap good for hiking but you may prefer one of the others.
- Name your area and pop in your email address - you'll be notified when the map is ready to download
- Click extract
- When you get the email, download and unzip map file, the map data is contained in
gmapsupp.img
Now see below for how to install that on your Etrex 10.
While the maps from bbbike are great, they can rub up against the limitations of the Etrex 10 in annoying ways. With limited space on the device, you can typically only have map coverage for a small area. With the small monochrome LCD screen, some maps look good when zoomed right in to say 5m scale, but look terrible zoomed out to 50km scale.
With more effort it's possible to specify exactly what map scales you want to include on your device (you really don't need all of them, I promise), blend elements of different maps together (say, mix a map of hiking trails along with a general topo map), and use different maps for different scales - I like a topo map up close, and a street map at a wider view.
Warning This is fiddly, it takes time, the software is a bit clunky / crash-prone, and it helps if you've worked with digital mapping / GIS in some capacity to understand the concepts.
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Collect your maps. You can collect a range of different mapping for free online, here's the sources I use:
- extract.bbbike.org: OpenStreetMap and OpenTopoMap layers
- Contours Australia: I found this courtesy of Geocaching NSW. It's a topographical map of Australia on a 5 - 50m scale.
- Shonkymaps: This is a set of Australian maps for Garmin usersthat are quite good.
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Convert to MP format. Use GPSMapEdit for this.
- Before starting go to
tools > options > Load & Save > Settings for Polish format - Change the second section to
as "CityName=".... and click ok / get out of settings - Open a map file
- Use
tools > remove object duplicates file > save asand make it a polish format file- Open
Map Properties > Levelson the toolbar - Use the trim tool to limit your map to the area you need.
- Delete any levels you don't want (trial and error). You might want to save after each remove.
- Before starting go to
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Merge. Open one map in GPSMapEdit then add all your others. Test at various zooms, then save as Polish format
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Clean. This may not be necessary, I had to delete a few things in a text editor to get clean output in MapTK:
- Any POI entries with type 0x283e
- Some labels have escape codes at the start.
s/\~\[0x..\]//gdoes the job
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Convert to IMG. Open MapTK and use
IMG/MP > Reorganise, thenIMG/MP > CompileNote: GPSMapEdit technically supports exporting directly to .IMG via MapTK integration, however I had issues with this during testing and chose to revert to using them separately. With the tips in this doc you might find that you can export straight from GPSMapEdit and save some effort.
- Ensure your Etrex 10 is set to Mass Storage mode in the settings
- Rename your exported .img file to
gmapbpmap.img - Connect the Etrex 10 to your PC and copy the file to
Garmin/gmapbnmap.imgNote: You're overwriting the default map - make sure you've backed your shit up. - Safely disconnect your device and start it up to see the new map.