Grade # in BT route tracker

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2008-07-15 12:25 PM

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Subject: Grade # in BT route tracker

Mike,

When mapping my rides in BT there is a %Grade # that is shown when mousing over a pt. The number seems to be quite off sometime.. I have seen it as high as 96% on one of my hills .. I can send you routes if you interested in correcting this bug 

2008-07-16 5:03 AM
in reply to: #1531077

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Champion
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Subject: RE: Grade # in BT route tracker
Can you send me some examples? Any time I've seen this, it was due to some extreme jumps in the elevation values retrieved from the USGS database.
2008-07-16 11:38 AM
in reply to: #1531077

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Subject: RE: Grade # in BT route tracker

Here is an example route

http://beginnertriathlete.com/discussion/training/map.asp?routeid=57513

here is a screen shot showing an example point, is it caused by the points on the route being so close?

 



Edited by slake707 2008-07-16 11:39 AM




(grade.JPG)



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grade.JPG (45KB - 29 downloads)
2008-07-16 11:56 AM
in reply to: #1531077

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Champion
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Fairport, NY
Subject: RE: Grade # in BT route tracker

Yes. The smallest distance increment that's taken into consideration when calculating the grade value is .01 of a mile or 52.8 feet. It looks like your route points are quite a bit closer than that.

Was this recorded with a GPS unit set to record every second?

2008-07-17 3:23 PM
in reply to: #1533979

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Subject: RE: Grade # in BT route tracker
This was a manually drawn route.. either by me.. or one of the other sites and then an exported gpx
2008-07-17 3:35 PM
in reply to: #1531077

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Subject: RE: Grade # in BT route tracker

Testing with a large pt separation still shows flaws in the logic.

These two points are clicked by me.. with no elevation reset.. they are .12 miles apart with a change of 95 ft

Math -> 95/( .12*5280 ) = 14.99%
The grade number shown is 51% .. that is closer to 95 meters in elevation in .12 miles

 



Edited by slake707 2008-07-17 3:38 PM




(grade2 (Small).JPG)



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grade2 (Small).JPG (36KB - 30 downloads)

2008-07-17 9:53 PM
in reply to: #1531077

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Champion
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Fairport, NY
Subject: RE: Grade # in BT route tracker
Ok, thanks. I'll find out what's going on with it.
2008-07-31 7:19 AM
in reply to: #1531077

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Champion
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Fairport, NY
Subject: RE: Grade # in BT route tracker

This is better now.

 

2008-07-31 3:35 PM
in reply to: #1531077

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Subject: RE: Grade # in BT route tracker
Awesome.. I tried it out in a few places and it seems much more tru to the number.. thanks
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