Hi, working with dodgr on walk and bike profile I came upon a slightly annoying issue.
Using standard profile, I get very high travel times, implying very slow speeds. Looking for the source of the problem, I think there is something wrong in the dz calculation.
From a silicate network, dz is calculated in sc_edge_dist as the difference between altitude of starting point and ending point.
However, dz is then used in tobler cost function (using standard parameters, https://en.wikipedia.org/wiki/Tobler%27s_hiking_function) as such. But Tobler cost function (given those parameters) must rely on the slope, not on the altitude differential. So it would be preferable to caculate dz as a slope, ie. "dz" = (.vx1_z - .vx0_z)/d.
I guess that using this formula would solve the issue?
Hi, working with dodgr on walk and bike profile I came upon a slightly annoying issue. Using standard profile, I get very high travel times, implying very slow speeds. Looking for the source of the problem, I think there is something wrong in the dz calculation. From a silicate network, dz is calculated in sc_edge_dist as the difference between altitude of starting point and ending point. However, dz is then used in tobler cost function (using standard parameters, https://en.wikipedia.org/wiki/Tobler%27s_hiking_function) as such. But Tobler cost function (given those parameters) must rely on the slope, not on the altitude differential. So it would be preferable to caculate dz as a slope, ie.
"dz" = (.vx1_z - .vx0_z)/d
. I guess that using this formula would solve the issue?