Tag Info

Try http://www.gpsvisualizer.com. In the parameters set "Add DEM elevation data" to "From best available source". This will replace the recorded elevation with elevation data from a database, which should be more accurate. Edit: Try this other sub-page of the same site to upload your .gpx and then download the fixed .gpx ...

Most of the Garmin Edge series GPS cycling computers can display grade. The Edge 500 and Edge 800 (not the Edge 200) have barometric altimeters to determine altitude. You can then change or add a display data field to show the current grade. Funny you ask as I just put added the grade as a display field this morning on a hilly ride. It updates the grade ...

Pain in the ass, and waste of money. As of the last time I checked, you can't track them directly (there'd be no way for you to receive a signal from a battery-operated device 5mi away), so you need to sign up for a recurring monthly service. On top of that, they chew through battery pretty quickly, requiring a recharge every few days. Contrast that to ...

I have a background in developing consumer GPS systems...... There is no doubt that a Garmin is a much better device for the job. On cell phones, GPS and associated functionality is the side dish - as in "would you like fries with your burger", on a Garmin, is the Raison d'être. Hardware wise, its a no brainier. First, as already mentioned in @armb ...

One option would be to use an iPhone. If you use software such as MapMyRide you can integrate it with ANT+ sensors to measure speed, cadence and even heart rate. These sites also have excellent mapping, training review and history functions. Pros: You can use your existing phone rather than needing separate hardware The online version of mapping software ...

You might want to look at the Biologic ReeCharge by Dahon. It says it hooks up to any standard dynamo hub. The nice thing about this is that it has it's own battery. So the dynamo changes the internal battery and the battery charges your phone/gps/device. This allows you to change while you are resting, as well as provide added protection against sending ...

Since you can't fine tune your wheel size, the bike computer likely is estimating your wheel to be larger than it actually is, causing this discrepency. This is because a larger wheel covers more ground per revolution, so over time that adds up to a sizable difference and probably scales pretty evenly with whatever distance you cover. You may need to get a ...

Here's one option: http://h1987995.stratoserver.net/magento/supernova-the-plug-ii-plus-usb-dynamolader.html SUPERNOVA The Plug II Plus USB power supply Transforms dynamo AC to exact USB spec. DC 5V, 500 mA E‐Bike compatible for 12‐ 48V DC with optional cable Works with Garmin, Ipod&Iphone 3GS & 4G & 4GS Seems pretty expensive at €159, but ...

You will obviously be able to get this from your trackpoints, but it can be useful (depending on the frequency of collection of trackpoints) to take speed - directly from your front wheel tacho if possible. This just gives you a higher degree of accuracy. Other nice to haves: accelerometer input - both fore-and-aft, and left-and-right - these can give a ...

Pressure sensor / altimeter. http://www.meas-spec.com/pressure-sensors/board-level-pressure-sensors/altimeter-pressure-sensor-modules.aspx The best one of their sensors can detect a change in elevation of 10 cm. I2C interface. These are really great. Bosch makes a sensor with similar quality. Of course the most interesting and most difficult to measure ...

It largerly depends on how you are marking the route in Google Earth and how you actually ride it. There are a couple of factors that introduce small diferencies when measuring distances and their effects are multiplied over distance, so the longer the route, the bigger the difference. The straight line effect For example, if I plan my route drawing a line ...

Others have already discussed GPS and GPS-enabled phones, altimetric barometers, and inclinometers. Bubble inclinometers (such as the Skymounti shown elsewhere among the answers) can be affected by acclerations so to get the best readings you should be stationary. dGPS (differential GPS) is used in surveying instruments to measure grades, but these are ...

When you import a GPX track into Google Earth, it offers to adjust the elevation data to match their internal database of worldwide elevation. From there, you can export it as a track again, to use as you wish. Thanks to the simple reality of how GPS works, elevation data is never going to be as accurate as lat/lon position. Even with expensive setups the ...

Cell phones, usually not. Some applications will attempt to massage the data using elevation information provided from third-parties, but its a crapshoot at best. A dedicated GPS with a barometric altimeter is probably your best bet. I can't really speak to their level of accuracy, but it's certainly better than other practical options. If you just want ...

Curiously, I've been tinkering with GPS data analysis (taken from some multi-kilometer randonnees, gpx format). Since you have the 4D trajectory (latitude, longidude, elevation and timestamp), you could theoretically get any derivative or combination of it. For example, currently I am calculating, for each pair of consecutive points in the trajectory: ...

Barometric altitude is far more accurate than GPS over several hours IF you have it corrected for the air pressure. Air pressure does not vary quickly. So if you calibrate a barometer to a known altitude (using a marker, sign, map, or very good GPS fix) it is much better than GPS for measuring an altitude profile

I use Motion-X as my tracking app and it can certainly import GPX and then navigate from it. It supports some ANT+ (at least HRM). Additionally the OpenStreetMap wiki has a good list of iOS apps comparing their functionality.

I won't ever go back to not riding with a non GPS bike computer. I've used the Garmin Edge 500 for almost a year and have used a Garmin wrist watch to record before that. Having the computer on the stem is much better than my wrist. I have never used a bike GPS for navigation, just as a bike computer to show speed, distance, cadence, HR and power (ANT+ ...

The wheel sensor add on will do quite a bit to improve the accuracy of the GPS based current speed. The distance will generally be accurate, to within error values of 50 meters, or so depending on hardware. Most phones, especially with android, are on the lower spec of GPS design, using wifi databases and cellular triangulation to augment the GPS positioning ...

Mobile is the way to go. Forget cycling computer. Cycling computer can't connect to computer wirelessly, your mobile can. I've stopped logging my rides on my mac, my mobile do this for me automatically and I can access the logs from anywhere. You get maps for free on your mobile from the internet and you don't have to update your map. You don't need ...

You might also consider buying external battery for you Android phone. I do not want to reccomend anything as I have not tried it, so here is plain Google search on topic. Of course, it will add weight to your backpack.

If you are using the device for turn by turn directions, then the Garmin 800 is really the only available choice which meets all of my requirements for a cycling computer with GPS. If you don't need turn by turn, consider the 500. It's got all the othe features, except the tur by turn. I've tried the iPhone, but the lack of integrated sensors and good, ...

A new product, SpyBike, is out on the market and it partially negates the claims I made in my previous answer. The website is hideous, but the general idea appears to be: It sits invisibly in your head tube, under your stem cap. You wave a keyfob over it to "activate" it when you leave your bike somewhere. This way, it remains completely disabled and ...

@freiheit answered above, but I highly recommend strava.com as the added component of segments and battling it out with my friends over a section of road whether or not we are riding at the same time, or even if we are, seeing how much time I took back (or gave up) on a hill is pretty cool. With a paid membership they add additional ride analysis, such as ...

You've got a small handful of choices for GPS enabled bike computers. In the world of bike GPS, Garmin has the market all but locked down. They currently have 3 models to choose from, all relatively new, with the most recent addition being the entry level 200 model. Your choice here is all finding a balance of budget and features. The 200 is inexpensive but ...

I wouldn't be surprised to find a 5% discrepancy, though 10% sounds a hair large. Google has actual mileage measurements for major highways, but for minor roads they must estimate. The Google estimates will generally be a bit short, because they don't quite have as many twists and turns and, especially, ups and downs as "real life". There's also the point ...

If you have an iPhone or an Android phone there are various free options, some based on OpenStreetMaps, but even Google's own solution is excellent. For google maps you can download areas to store locally (for those areas you know you will have no connectivity) and it is free! I'm playing a lot of Ingress at the moment, which requires 10 - 20 hour stints ...

The Garmin is waterproof, and has a resistive touchscreen that works with gloves. It has an ANT+ receiver for use with cadence sensors etc., and most phones don't. Battery life will be better than most phones. I suspect the Garmin will be easier to load maps onto than a phone with no plan, but many mapping apps do allow you to load data for later use without ...

There is one use case I think will suit you greatly if you get your phone to work AND get some app that saves GPX files (I think most GPS-oriented apps do that): When you go out for a ride, you turn the phone on, get a GPS position, throw it in your back pocket and forget it. When you get back home, you transfer the GPX file to some service (Strava and ...