Maximum Nerdage - GPS track + Google Earth

El Chupacabra and I did a morning sesh yesterday at Mt. Rose, and I turned my GPS on in my pack before we started. I was able to record a track of everywhere we went, in addition to our total vertical footage with the baro altimeter (which was only about 11K in 2.5 hrs...we're slow...)

In a fit of boredom, I decided to map our track against the 3D map in Google Earth. What's the point? I dunno, but anyone with a sense of geekdom can appreciate. Now if I could only get a trail map overlay. :cool:

http://www.jacobsonmachine.com/photo...ose.013106.jpg

I decree that all future TR's include this data.

What? Is Wild Card closed down or something?

There was 8-10" of fresh everywhere. Plus, the W side was kinda blown thin, so the best depth was in the Chutes. I do love Wildcard though.

looks like your skis never left the ground, brah.

Sorta confused about that lift ride with no ins or outs... did you turn it on at the bottom of the lift?

Were you able to overlay GPS data in standard Google Earth or do you have the Plus edition? I've been wanting to do this for some time, but Google Earth for Mac OS X does not seem to support GPS data input yet (or do I have to make my own kml file?)

Thanks,
-Geek Fan

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Originally Posted by Pope Benedict XVI

Sorta confused about that lift ride with no ins or outs... did you turn it on at the bottom of the lift?

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That is a mystery. It's possible the receiver lost signal for a short time between the bottom of the NW run and the return to the lift base(the error is pretty apparent from the fact that it shows I skiied across the highway.)

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Were you able to overlay GPS data in standard Google Earth or do you have the Plus edition?

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I downloaded an app for Windows called GPS Trackmaker (I tried to use CompeGPS, but the download map feature wigged out, and the sat maps for Mt. Rose that I could get were summer.) GPS Trackmaker imported my track directly from the GPS, then I just clicked "Display in Google Earth" and it overlayed the track data. I set the elevation exaggeration to "2." I think the free version of Google earth can import and display XML track data(kml), but GPS Trackmaker generated the file for me. You might look for something on OSX that can do the same.

Check it out! it shows where you hit the main side switch and rode it through the trees, all the way into the road, brah!

(What happened there anyway? Your GPS show you traveling waaaay the hell out over Mt Rose Hwy.)

This is cool. What sort of GPS unit. I've been avoiding the market, but it's time.
Suggestions

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Originally Posted by El Chupacabra

Check it out! it shows where you hit the main side switch and rode it through the trees, all the way into the road, brah!

(What happened there anyway? Your GPS show you traveling waaaay the hell out over Mt Rose Hwy.)

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You don't remember that? Sorry about the asphalt gouges in your Bros.

I dunno, sometimes if the receiver loses a satellite, the resolution goes to shit and it gets confused for a few minutes. It was in my pack. Maybe I should mount in on my helmet for best reception?

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What sort of GPS unit. I've been avoiding the market, but it's time.

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Garmin eTrex Vista C...I've been very happy with it. I chose it for the magnetic compass(at low speeds) and the barometric altimeter, since I had planned to use it mostly for paragliding.

Wow, thats pretty sweet. One more reason why Google Earth is so awesome...

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Originally Posted by bio-smear

Maybe I should mount in on my helmet for best reception?

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Well remember, with this setup you should be pretty set!

http://www.tetongravity.com/usergall...alpdhuez10.jpg

That actually is pretty sweet.

as a geographer and a skier and a nerd I think this is the coolest thing eh-ver!

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Originally Posted by A-wreck

That actually is pretty sweet.

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I concur.

...and being that we all belong to an internet community, I think theres's a good deal of nerd/geek in all of us...

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Originally Posted by bio-smear

Garmin eTrex Vista C...I've been very happy with it. I chose it for the magnetic compass(at low speeds) and the barometric altimeter, since I had planned to use it mostly for paragliding.

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This is VERY cool shit. Is it possible to overlay your track onto a topo map with that Garmin? If it's painfully easy to do so, please forgive - I am a techno-idiot.

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Originally Posted by Tin Woodsman

Is it possible to overlay your track onto a topo map with that Garmin?

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Garmin Mapsource + Mapsource US Topo West CD-ROM: Pretty standard stuff. It gets tougher when you use 3rd party apps to overlay tracks, like above, although that wasn't very hard either.

That's pretty cool. You should upload your data to motionbased.com. It's very easy to use, and they have an algorithm to correct your elevation data. (Skiing 4,000' runs here through varying temps screws up the barometric altimeter in my eTrex Vista.)

Highly recommended!

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Originally Posted by bio-smear

I dunno, sometimes if the receiver loses a satellite, the resolution goes to shit and it gets confused for a few minutes. It was in my pack. Maybe I should mount in on my helmet for best reception?

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Yeah, I've found that the GPS receiver loses a signal in my pack combined with the mountains, trees, etc blocking the satellites.

very very cool. would rock for BC route finding.

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Originally Posted by spanky

Yeah, I've found that the GPS receiver loses a signal in my pack combined with the mountains, trees, etc blocking the satellites.

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GPS antennas can be finicky. Usually, they will pick up a signal through clothing, or through the top of a pack -- but if the eTrex flips upside down it might stop receiving.

Canyons are pretty tough for tracking, and heavy tree cover is an issue.

I've been using the eTrex Vista for, hm....at least 5 years now, and I've had every result imaginable with it (from horrendous/i-want-to-throw-it-out-the-window to you-saved-me-by-helping-me-ski-right-back-to-my-car-on-a-tour). The best mount would actually be atop your helmet, but it's not so practical for viewing the device.

Body parts (even holding it upright in your hand) seems to attenuate the device's ability to receive a signal pretty bad.

Weird, I know.

When it works, it's awesome.

Very cool nerdage. I put My Garmin Legend in the top pocket of my pack (when hiking) and it almost always gets a good signal.

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Originally Posted by bio-smear

Garmin Mapsource + Mapsource US Topo West CD-ROM: Pretty standard stuff. It gets tougher when you use 3rd party apps to overlay tracks, like above, although that wasn't very hard either.

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Awesome. But that topo is pretty broad brush. AAre there any software packages that approach/approximate a standard USGS 1:24,000 series?

I've been using this 6,000 dollar piece of shit for work. http://www.trimble.com/geoxt.shtml The thing only gets a signal if the sky is completly devoid of clouds, and recently ArcPad has been shutting down whenever it damn well pleases, meaning I spend the majority of my time sitting in my car rebooting. :cussing:

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Originally Posted by upallnight

That's pretty cool. You should upload your data to motionbased.com. It's very easy to use, and they have an algorithm to correct your elevation data. (Skiing 4,000' runs here through varying temps screws up the barometric altimeter in my eTrex Vista.)

Highly recommended!

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2nded! Motionbased is pretty durn cool - doesn't play so well with my eXplorist 500, but c'est la vie

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Originally Posted by Snow Dog

I put My Garmin Legend in the top pocket of my pack (when hiking) and it almost always gets a good signal.

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Same here...I'm going to try it sking tomorrow. Great idea Bio, and thanks for the tecy info.

Supposedly the newer patch antennas are improved over the older eTrex's. I sometimes run mine in my pack top pocket, sometimes in the front pocket of my shell (so I can easily check my vertical footage quota ;)) It makes a little beep when it loses signal, but for the most part it does really well, and there were only a few errors for the day. I am actually surprised at how much you can smother it and it will keep receiving.

If you think this is geeky, last season I kept a spreadsheet of my days. Location, skis, conditions, notes, partners, and any stats I could derive from those basic values. What else is a fuggin egghead supposed to do when all he can think about is skiing, but is forced to code shit?

I'm gonna give that MotionBased Lite a whirl. I draw the line at paying though, no matter how cool it is. :nonono2:

Hey bio-smear...
I'm curious how much of an adjustment you see with the altitude calibrations performed by motionbased.

For instance, for a couple hours of skiing MB totaled 19K vert for me (which worked out when I thought about the lifts I rode and hikes I did); in contrast, my GPS recorded over 35K. There were not many "dips" (short ups & downs), so I know that was not the culprit -- I think it's the intra-day fluctuation of the barometric altimeter in the Garmin unit that is the cause.

I'm interested to know what their "calibrations" are. I have yet to play with it[MotionBased], but the only way they could be correcting recorded altitude is by 1) Omitting outlying recorded elevations that are obviously erroneous, like a spike that occurs in an extremely short time interval(huge huck?) or 2) compare the altimeter setting(the calibrated sea level pressure) from the nearest reporting station(like Reno/Tahoe Intl Automated Weather Observation) records. Sounds contrived to me.

Temperature can affect realtime altimeter readings too. The problem MB is trying address I think is the jockeying around of readings due to varying temp for a barometric altimeter(rare), or signal irregularity for GPS altimeter(less rare.)

After searching their forums, they seem to want to smooth their elevation data out and eliminate the irregular points. I dont care how dirty my data is(if it's dirty at all.) My irregularities might be me throwing a switch-cork-7-dong-slap-grab off the Cutthroat rock.

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Originally Posted by upallnight

I think it's the intra-day fluctuation of the barometric altimeter in the Garmin unit that is the cause.

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Originally Posted by bio-smear

Omitting outlying recorded elevations that are obviously erroneous, like a spike that occurs in an extremely short time interval(huge huck?) or 2) compare the altimeter setting(the calibrated sea level pressure) from the nearest reporting station(like Reno/Tahoe Intl Automated Weather Observation) records. Sounds contrived to me.

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WOW.....NERDS!!

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Originally Posted by bio-smear

After searching their forums, they seem to want to smooth their elevation data out and eliminate the irregular points. I dont care how dirty my data is(if it's dirty at all.) My irregularities might be me throwing a switch-cork-7-dong-slap-grab off the Cutthroat rock.

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Yeah, sort of. After using their service for several years -- and specifically recording over 60 ski days with it this year, I've started to see that their corrected data is much more accurate than what my Garmin unit reports.

The cool thing is that they give you the ability to turn the correction on and off, as you like.

I'm curious if you do some experiment...like track some runs on a lift of known elevation, and compare what you think you should have to what your GPS reports & what motionbased calculates.

They have spent alot of time figuring out the calibration, and they discovered that the Garmin devices (a) record plenty of bad data and (b) fail to throw the bad data out. Garmin acknowledged the problem (when the MB team reported it to them), but chose not to do anything about it with "older" devices.

Motionbased is now part of Garmin, actually.

MB is focused on tools for endurance athletes, but it's interesting stuff (to me) nonetheless.

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Originally Posted by upallnight

I've started to see that their corrected data is much more accurate than what my Garmin unit reports...
...what motionbased calculates.
They have spent alot of time figuring out the calibration...

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Upallnight-

Can you tell me what they're correcting exactly, other than eliminating bad points? It seems like without benchmark reference data, there is no way to correct a single altimeter reading, or determine if it is erroneous. I can see correcting summary data, like total vertical, by recalculating from the raw data, but I'm having a hard time understanding how they reject certain points. I'm sure they know what they're doing, I'm just having a hard time getting it.

The Vista C has an altitude calibration page where you can specify a known elevation, and it will calibrate all readings from that. I rarely do that though, and hadn't given much thought to the accuracy of my data. Important for instrument flying maybe, but for skiing I can accept some high tolerances.

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Originally Posted by Tin Woodsman

Awesome. But that topo is pretty broad brush. AAre there any software packages that approach/approximate a standard USGS 1:24,000 series?

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I used OziExplorer to overlay the track from a tour around Shuksan Arm at Mt. Baker onto a standard USGS map. Click the thumbnail to see a larger image.

http://img188.imageshack.us/img188/8...narm3lg.th.jpg

I gotta get me one 'a these.

Too bad Google Earth's resolution in the Alps is horrible, but still it's inspiring me to get a GPS. Why? What's the point of something like this? I dunno but it's somehow kinda cool!

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Originally Posted by bio-smear

Upallnight-

Can you tell me what they're correcting exactly, other than eliminating bad points? It seems like without benchmark reference data, there is no way to correct a single altimeter reading, or determine if it is erroneous. I can see correcting summary data, like total vertical, by recalculating from the raw data, but I'm having a hard time understanding how they reject certain points. I'm sure they know what they're doing, I'm just having a hard time getting it.

The Vista C has an altitude calibration page where you can specify a known elevation, and it will calibrate all readings from that. I rarely do that though, and hadn't given much thought to the accuracy of my data. Important for instrument flying maybe, but for skiing I can accept some high tolerances.

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I believe they're tossing out the data from the internal barometric altimeter and using the GPS elevation from their database. They are then tossing out the random GPS data points that do not seem to correspond to the rest of the activity.

For more detail, it's probably a question best asked in their forum. The developers will respond (if they haven't already written a thread on it).

I calibrate my altimeter reasonably frequently, but even if I do it once per day I have noticed that the vertical displayed on my device for the day can be up to 2x my actual vertical (in terms of distance I covered, whether on lifts or on foot).

YOUUUUUUUUUU FUCKINGGGGGGGGGGGGGGGGGGGGGGG NEEEEEEEEEEEEEEEEEEEEEEEEEEEEERDS!!

Pretty cool shit admittedly though :fmicon:

That's cool. I used a Vista all last summer to make maps of road rides around here last summer along with elevation profiles. I gotta get a PC, though - GPS geek stuff is hard to find for the Mac.

Has anyone tried the new Garmin Edge? Looks nice, and has rechargable batteries.

Does the fact that I know exactly what they're talking about, yet could never actually explain it to someone else make me a nerd as well? Maybe it's the closet nerd inside of me trying to escape......or maybe it's the "cool guy" in me trying to take over the nerd that I actually am.

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Originally Posted by tomw_n

YOUUUUUUUUUU FUCKINGGGGGGGGGGGGGGGGGGGGGGG NEEEEEEEEEEEEEEEEEEEEEEEEEEEEERDS!!

Pretty cool shit admittedly though :fmicon:

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We already have a nerd basher here by the name of Oger... although he has been Noticeably absent from this thread...

Are you gonna kick sand in our faces and then steal our bitches?

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Originally Posted by bbirtle

I gotta get me one 'a these.

Too bad Google Earth's resolution in the Alps is horrible, but still it's inspiring me to get a GPS. Why? What's the point of something like this? I dunno but it's somehow kinda cool!

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The height data's not bad though so the 3d stuff looks pwerty :)

edg