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Discussion Starter · #1 · (Edited)
I just bought a garmin geko 301. I have read the basic instructions, but it does not explain how best to use it for mountain biking, in particular the trip computer aspect. Could someone explain the steps to take prior to starting a mountain bike outing? What do you do just prior to starting your ride, and what to do to at the end, and then how to analyze the data on my computer. I would greatly appreciate any direction. Thanks.

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I'm sure you figured it out already but for everybody else, here's what I do:


1. Turn it on
2. Calibrate compass if you removed a battery since last calibration
3. Wait for a good signal (hopefully <20' accuracy)
4. Clear elev data
5. Clear trip data
6. Clear track data

All that stuff is in the users manual but here are some tips:

--If there are track points left still in the log from last time you used the GPS, they will be connected to any track points you make now. If you are logging a multi-leg journey, this might be exactly what you want. Then again it might not, because there is a max # of points per track (forgot what it is), so for a very long track, at some point you will begin to lose resolution.

--if you know there are no previous tracks in there, clear it anyway because as you connect with the satellites, you may drop some track points that are far away from your actual position. This will inflate your distance, avg. speed, etc. and make an ugly scribble at your start point.


1. Save the track
2. Go home and upload the track to whatever application you want.

--When you save the track you can choose the start and stop points. Maybe you forgot to turn it off when you drove home. No problem - you can just drop the stop point at the place where you really stopped and the points after it will be excluded. You don't get to choose the name of the track. The naming convention is DD-MMM-YR. If you save more than one in a day, that name has a suffix "-2", "-3", etc.

--Once you save the track, the unit shows you an overview and a length. This number should be larger than the number you have in your trip data, because the altitude data is used to calculate the distance in 3 dimensions instead of 2. As long as you got good reception for the whole ride, this value may even be more accurate than what you get from the application on your computer that you plot the track with. That's because the altimeter may be more sensitive than the topo resolution on your base map on your computer. Even though it's just a barometer, and may be calibrated way off because of the myriad things affecting pressure around the sensor other than just altitude, it's ok because a change in 10' elevation is the same no matter what elevation it thinks you're at. So even when it's not ACCURATE it's still PRECISE

--The Garmin brand interface cable is expensive! Mine is from Gilsson and works beautifully. Wish it was USB though.

--Don't forget to turn off your GPS when you're done uploading!

--There are lots of mapping softwares you can use. National Geographic TOPO! is good but it's expensive, especially if you want base maps for a large goegraphic area like the whole country. Also the base maps are scans of the USGS 7.5' quads which results in small problems at seams. The DeLorme one is much less expensive for the area that it covers, but the native digital topo data is lower resolution. You can plot the USGS quads in the DeLorme application but you have to buy them individually. You can also plot USGS imagery with DeLorme but again you have to pay for the images. It is however extremely easy to do this directly from the software, which is a big plus.

You can download ALL of the USGS data for free at the USGS SDDS website. Your taxes already paid for it! The problem is that bandwidth forces a 100MB per download limit. With heavier software, you can download the data free (in pieces), stitch the files together, and plot your track. These applications are not designed for novices though! There is a reasonably priced tool called Global Mapper that looks very nice for the price but I haven't tried it yet.

I love a software called 3DEM that lets you render your track on a 3D elevation model, over which you can lay aerial or remote imagery. 3DEM is free and so are the model and the photos (from SDDS). The problem here is that 3DEM only lets you submit one single model and one single overlay, so you can't stitch together more than one, if you need to cover a large area. The coolest images are also the largest ones, so you'll have a hard time covering your whole track with the really awesome hi-res full color data.
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