I’ve ridden with the Dakota 20 quite extensively over the last couple months — about 1000 offroad miles according to the odometer on the unit. My conclusion is that it is a solid GPS for cycling and bikepacking.
The biggest reservation cyclists have with the touchscreen Garmin units is that of screen visibility when used on the handlebars. The Dakota 20 is an improvement over the Oregon 300t I previously owned, and is good enough for most situations. With certain angles of bright light the screen is hard to read, but the difficulty is not enough for me to give up on the unit, like I did with the Oregon 300t. The only situation I would not use the Dakota for is racing — when quick confirmation of the route ahead is critical. For normal exploratory rides and everyday shredding, it works fine.
Edit in 2011 – I have found that using polarized sunglasses makes a HUGE difference in the readability of the screen in the sun. I am now regularly using this GPS on the handlebars.
Use in hand
In the hand, the GPS is fun to use. It came in quite handy when I spent a week doing trail layout in a remote location. Having USGS 24k quad maps with my current location on them, was very useful in planning ahead and for quick orientation. When the unit is held in the hand it is easy to orient it for maximum visibility, so that issue is really only annoying when the GPS is fixed to something (e.g. handlebars).
In the accuracy department, I think the Dakota is a small step above older generation units. It is very quick to find its location, and in taking daily waypoints at a surveyed brass cap, the Dakota did better than my crewmate’s 60CSx. Tracklogs come out well, as expected. I have only noticed the expected number of anomolies here and there.
Battery life is shorter than a 60CSx or VistaCx, but still quite acceptable. I tend to get ~15 hours with years old rechargeable batteries.
Things I like:
1) Small and light unit, big screen. Similar in size to the VistaHCx, but larger screen.
2) Faster CPU – menus and maps respond and draw much faster than older units.
3) The custom maps – this feature is huge, never before seen on a Garmin GPS. As soon as I heard about it, I worked hard to add full support to TopoFusion. More about this in its own section below.
4) Track manager – no need to split tracks into 500 point chunks anymore. Just keep the track under 10,000 points each and you can quickly get it onto the unit. Much easier! You can also store quite a few 10,000 point tracks, and easily turn them on/of, look at profiles, etc.
5) HR / Cadence – I have a Garmin HR strap from an older Forerunner GPS, and the Dakota picks it up and stores heart rate data in the GPX, which is then read by TF.
6) Triaxial compass – I rarely use the compass when riding, but for trail layout it was nice to not have to hold the GPS level to get a solid reading.
Things I don’t like:
1) There’s no setting to change the color of the active tracklog. It’s always black and sometimes hard to see.
Edit in 2011 – you can change this now.
2) You can only have 100 custom map tiles. This amounts to about 580 square miles using the Topo 4m tileset (USGS 24k maps). Good enough for most epic rides, but not for a multi-day bikepacking trip.
3) No ability to turn on/off different custom maps. You can have overlapping maps, and the draw order can be controlled in TopoFusion, but it would be nice to have both topos and aerials for an area and be able to choose between the two.
4) The touchscreen is neat to use when you’re not riding, but I’d prefer tactile feedback when the wheels are spinning. Sometimes you hit a button and don’t know if you really got it.
5) Track archiving is a little strange. The unit saves out a new GPX file every 10,000 points (roughly). I think the way the Vista or 60CSx does it (archiving one track per day and naming it by the date) makes a lot more sense and is easier to deal with.
Edit in 2011 – there are some new options for this as well.
Note: hopefully the first three will be corrected by firmware updates in the future. Maybe the 5th as well.
Tips for using Custom Maps on the Dakota/Oregon/Colorado units:
2) With your GPS plugged into your computer, create a directory called “CustomMaps” in the “Garmin” sub directory on either your GPS itself, or the SD card. Map images in the .KMZ (google earth tile) placed in either CustomMaps directory will be automatically loaded by the GPS.
3) Use TopoFusion — it has the ability create large scale KMZ files from any of the available imagery in the software. That includes 24k topos and high res color aerials for most of the country. You can also add your own custom maps to TopoFusion and upload those. Just use the “File->Export View” command to get started.
4) Use the custom maps feature to upload tracks, too. Anything that is displayed in TopoFusion gets rendered and put into the custom map. That means you can have hundreds of GPX tracks loaded and they will all show up on the GPS. No more simplifying and splitting of tracks, worrying about whether it’ll all fit or not.
I have found this to be extremely useful. I can load up (or draw) several tracks in an area, change their colors/widths, and then get them all very easily onto my GPS, laid over a highly detailed basemap.
This is hands down the best way to get a GPS network onto a GPS for use in the field.
5) Use Topo 4M. I’ve found that the white background on Topo 4M makes the map more readable than the Garmin vector basemap (e.g. Topo 2008 DVD).
In addition I recommend 4M to cover more area (than Topo 2M) and also so that tracks you have loaded end up thicker and easier to see. You may want to add additional thickness to your tracks by right clicking on them in the map and choosing “Track Properties.”
6) Aerial photographs are cool, but harder to see. I definitely get a kick out of passing a big building and seeing what it looks like from the top, but aerials tend to be a little dark and tough to read outside on the Dakota and Oregon screens.
7) Remember that you can only have 100 map tiles on your GPS at a time. TF will give you a warning message if you generate a single KMZ file with more than 100 tiles (the number is displayed as you zoom in and out and choose a tileset as well). But even across multiple KMZ files you can only have 100 tiles total. So, be careful.
8 ) You can use Google Earth to preview the generated KMZ file and see what you have. It will look less pixelated on the GPS since Google Earth resamples the map tiles and loses some quality. Still useful to verify what you have.