Archive for the ‘gps’ Category

Route in Google Earth and transfer to Garmin GPS (part 2)

September 21, 2012 2 comments

Updated 9/21/12 using google earth version

In this guide you will learn how to get any sketched or routed path from Google Earth directly to your Garmin GPS.

I got an email request for an update to using standalone Google Earth software with a Garmin GPS.  Everybody knows I stive to keeping perfect customer satisfaction rating, so here is my update.  Please refer to part 1 if you are still using older version of Google Earth.  This post will be using Google’s latest v.

There are several ways to get info into your personal GPS, but this method is the cheapest method(free) without having to sign up for another web account service.  Besides, its just so cool when you can integrate Google earth with any GPS.

1. Install GoogleEarth for your computer

2. Install Garmin Mapsource

3. Reboot your machine

4. Start your GoogleEarth

5a.  There are two options now.  You can use “Add Path” icon from Google earth to sketch your route.  Once you are done sketching goto step11.

5b.  or if you want Google Earth’s calculated directions proceed to step 6.

6. Create all your “Placemarks” first. This sets up a point to point connection of your path

Note: Once you initially hit the placemark icon, you will need to drag and drop it to specific location.

6.  Place your mouse cursor over the starting placemark, right mouse click, and click ‘Directions from here’

7.  Place your mouse cursor over the next placemark, right mouse click, and click ‘Directions to here’

8.  Click icon for ‘Copy the current search results to My Places’.  This moves directions and route to ‘My Places’

9.  Repeat steps 6 to 8 until all the routes are created and moved into ‘My Places’ box.

10.  Here is what it would look like after you connect everything up. My routes are in blue, also notice all the connections I made on the left side of the screen

11.  Once you are happy with your newly created route(s), its time to get it ready for your Garmin GPS. Go to “My Places” in Places box/right mouse click/Save place as/<route_name.kmz>

Note: DO NOT use the upper left File/save/Save place as…

12.  Open up your web browser to GPSvisualizer.

13.  Browse for your .kmz file, be sure to set output file to .gpx, and hit the ‘GO’ button. Your form should look like this.

14.  Click on your shiny new .gpx file and save it to your computer

12. Open up GarminMapsource

13. Open the newly created .gpx file from step 14.

14. Connect up your Garmin GPS to your computer

15. Click Transfer/send to device.



Part 3 will be a guide to using Google and GPS to mark your own property boundary, with excellent correlation!

Categories: gps

Is my gps elevation data correct?

October 14, 2011 8 comments

This topic seems to come up over and over so I figure I’ll just post it here and forward this link instead of writing 300+ word document every time.   Determining the “correct” elevation gain is going to be somewhat subjective and we are limited by the consumer-grade device and its software that plots it.  First topic I want to touch on is gps elevation vs. atmospheric elevation.  The choice comes down to accuracy.  GPS does great job determining “X & Y” position but its not so accurate in the Z, in comparison to using atmospheric pressure baseline.  One can argue you can be cycling along air mass front, weaving in and out between cold and warm air masses.  There are instances like this where your atmospheric baseline will be way off, but in normal comfortable weather condition an atmospheric pressure based data will be more accurate than the gps reading.  Although the error difference may be miniscule for short sampling/ride, if you consider 5000+ data points for a century ride, the error can basically make your valuable data worthless.  Now keep in mind I am comparing consumer version of the gps to consumer version of barometer device.  There are ones used by NASA and the military that really isn’t worth discussing here.

So assuming we have a good device that plots air pressure based elevation, its now worth discussing why there can be such drastic total-elevation number between a two similar/identical devices.  Chances are both data are correct, your “data recorder” is doing what its being told to do, collecting data points.  The root of the problem is lack of standardization.  Consider these questions:

1.  How often should the device take a data in?

2.  What should the minimum delta elevation be in order for a grade to be considered a hill?  Novice rider and pro rider will interpret this very differently. 

3.  Should data point be collected based on time, distance, elevation difference, or a more complicated equation?

4.  Should the elevation data be collected using same formula for when you are hiking, cycling, or riding in your car?

5.  Is your elevation parameter set properly for your fitness level and your choice of locomotion?

6.  How are you using your elevation data? bragging right? for your specific fitness?

For simple example, if your gps took 100 data points but your buddy’s gps took 100000 data points for the exact same loop, on a perfect day, at the same time, the guy that took 100000 data points will have a data result that shows he completed stage 18 of 2011 Tour de France!  Standardization is the key if you want to compare data to your friends.  Lot of good devices offer various ways to take elevation readings and you can play around with its parameters to suit your need.  A cheaper device may allow you to export your elevation data in ascii format so you can really go crazy with M.S Excel.

I found Garmin to be a top notch gps system for processing elevation data.  Its menu does offer reasonable flexibility with the way it collects its elevation point, but more importantly, its Garmin Connect website offers “elevation correction” option for every workout you upload.  Its Garmin’s way of somewhat standardizing everybody’s elevation data.  The elevation correction isn’t perfect but I think it’s the best tool available for comparing other rider’s workout.  Standardizing on data-over-“x”distance would be the simplest method I can think of, because most gps offers that as an option.  Keep in mind, even with the Garmin elevation correction, the data result can still be skewed by quantity of samplings and the way the sampling was taken.  Like I said, its not perfect. 

One last note.  Please don’t bring up iPhone’s gps cyclemeter into this conversation because its basically a toy compared to real instruments like the Garmin series.

Categories: gps
%d bloggers like this: