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Roadtrip
09-16-2010, 11:23 AM
OK. I found this site (most likely already knew about this site) and entered in the quickie route to my grocery store (just over a mile round trip) and found an oddity with the website.

http://www.cincylights.com/images/map_grocery.gif

It shows a nifty graph of the grade, but when I click out and back, the grades all change quite drastically. Now if I'm right, the grade of a hill does not change... it's pretty simple math of elevation gain over distance.

WHY does clicking out and back and thereby doubling the overall distance, make a 9% grade now 4-5%?

Does this look like a 9% hill or a 5%? It goes perhaps a quarter mile and does seem pretty steep, but I question 9%, so I'm wondering what ya'll thought.

http://www.cincylights.com/images/hill.jpg

Shannon

Owlie
09-16-2010, 11:45 AM
The joys of living in Cincinnati, right? :D

The reason that I think it does this is:
Look at the elevation profile. All it's doing to calculate the grade of the hill is what you learned to do in jr. high algebra: rise over run. It takes the known height of the hill and then divides it by the distance traveled. So if you double the distance, it will halve that hill grade.

Just my guess. Try clicking the top and bottom of that hill on the map and see what it gives you. That should be a more accurate picture of feet climbed vs. distance traveled.

Roadtrip
09-16-2010, 12:09 PM
OK. I mapped just the hill itself...

DANG.

http://www.cincylights.com/images/ouch_hill.jpg

It says 46 feet of climbing in .2 miles and some of that at the end was at the top of the hill.

Yeaaa.. joy of joys.. the hills of Cincinnati.

Owlie
09-16-2010, 12:27 PM
Guess I need to go home and practice. The hills around here don't hold a candle to them.
Also, that hill looks steep enough to have me screaming the whole way down. I'm such a chicken...

My neighborhood is excellent hill practice. Only problem is that I live at the top!;)
I need to find the elevation profile of the terrifyingly steep hill off the Little Miami trail. It's somewhere between Loveland and Milford, but I can't remember the name of the street.

Roadtrip
09-16-2010, 01:17 PM
I must admit I havn't been up (or down) this hill. I've walked it and driven it, but never on a bike...

DH has taken this route several times going to the grocery and he loves going downhill on this one.. said he hit 28mph coming down and was on the breaks.

warneral
09-16-2010, 01:19 PM
Is that a beta version of Map my Ride? I haven't seen those graphs before when I've mapped my ride...

shootingstar
09-16-2010, 01:21 PM
Admittedly I wouldn't be mapping my routes for the whole Internet world to see.

A general description/summary, is better.

Owlie
09-16-2010, 01:26 PM
I must admit I havn't been up (or down) this hill. I've walked it and driven it, but never on a bike...

DH has taken this route several times going to the grocery and he loves going downhill on this one.. said he hit 28mph coming down and was on the breaks.

There's one in my neighborhood like that. 27.7 and my right hand was cramping up.
Shootingstar: She's blacked out most of the road names, but I can see your concern. I could probably guess where she is, but that's because I grew up in the area.

Warneral: While you're mapping, there's a check-box that says "show elevation". It's underneath the "undo", "clear", etc buttons.

Roadtrip
09-16-2010, 01:26 PM
Admittedly I wouldn't be mapping my routes for the whole Internet world to see.

A general description/summary, is better.

I did remove all street and city names.. so yes, I did take some thought into posting that map.

warneral: if you click show elevation it opens up that box showing the grades of the route with all the pretty colors!!

Edit: I did edit the map image again.. positively no road names showing now :D

hebe
09-16-2010, 01:52 PM
I like that! What a hill though. I'm just mapping my epic trip from home to soft play and back. Hmmm, 1.97miles. Still, much faster than walking and a lot more exciting.

OakLeaf
09-16-2010, 02:41 PM
If you want a decent approximation of grade, use ridewithgps, or look at the USGS topo maps (http://viewer.nationalmap.gov/viewer/).

MapMyRide wildly understates grade and total elevation gain, and you've found a clue as to why. I didn't realize the contour lines got farther apart as you zoomed out, though!