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• #40802
1 Attachment
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• #40803
No.
Flatness is not about average elevation.
Flatness is about smallest distance between lowest and highest points. -
• #40804
dont let @BareNecessities come in here with Norfolk
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• #40805
It doesn't make sense to take the highest and lowest points because that doesn't take into consideration the "lumpiness" of the terrain. What if a country has a lower spread between highest and lowest points but goes constantly up and down vs another that is constantly flat (let's say in 99% of the surface), but has a highest maximum elevation (in 1% of the surface)?
Surely the latter is more flat, if the average elevation is lower than the former.
Hence, the average is a more significant measure of flatness -
• #40806
Must be a rest day.
What day are the cobbles?
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• #40807
Wednesday.
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• #40808
It will be interesting see how UAE, with seemigly no real support capabilities in the cobbles (at least in comparison do TJV), will deal with it
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• #40809
Probably the normal way, by letting Pogacar win unaided. He hasn't exactly shown any weakness on previous cobbled stages.
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• #40810
He hasn't exactly shown any weakness on previous cobbled stages.
And apart from being played by mvdp, had no problem at De ronde
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• #40811
I would hope that the newcomers Van Hooydonck, Laporte and Benoot can make a difference when they will get to the cobbles
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• #40812
Pogacar to pull a 2014 Nibali attack and shut down the GC
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• #40814
i really hate the belstaff mandate for all ineos riders
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• #40815
Wrong thread. >>>Stylish cycling kit
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• #40816
Is it 10km to go yet?
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• #40817
I see what you mean, but I don't think the average elevation in itself is the correct parameter to use as it just tells us how high above sea level the average is.
You want something like the lowest deviation from the median. :)
We need more data, but I can't provide it.
Edit: am just looking forward to some real mountains and proper racing. -
• #40818
Big mountains are boring. Everyone rides up looking at their stems and maybe chances an attack with 500m to go.
Bring on the cobbles, crosswinds and lumpy stages!
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• #40819
As a statistician by trade, I could talk all day what the best measure is. Let's leave it at this, tho
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• #40820
I think what you want is a metric like "mean topographic roughness". Topographic roughness would be calculated per pixel and captures the maximum elevation difference between a central pixel and all immediately surrounding pixels. You would then take the average value across the landscape of interest. Of course this kind of metric is heavily influenced by the scale of analysis and so you could then move the discussion along to an enjoyable debate about the appropriate scale of the pixels to be used. However, just for reference, last time I did this kind of work (>10yrs ago) most open access digital elevation models were available at 90m resolution.
Edit: It looks like this is essentially what this database does, calculated at a 30 arc second grid scale (~930m at the equator). On that metric, the Netherlands wins the "flatness contest" by a considerable margin... Netherlands 3.7m Vs Denmark 18.9m.
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• #40821
as a philistine i am 100 degrees sure that the best measure of flatness is average gradient
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• #40822
it’s basically Essex
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• #40823
only if you take the absolute value (or to the power of 2) of the average gradient, otherwise positive gradients offsets negative and viceversa
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• #40824
Hmm - rest day chat. #donotwant
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• #40825
Doesn't recent Lidar data measure the surface on 25 cm contours?
I guess we need average gradient of all roads to settle this matter ?