I'm trying to generate 15-minute pedestrian walking iso-areas from various points using QNEAT3 and the OS multi-modal routing network. The area is hilly and I want my map to accurately capture how walking uphill and downhill take more or less effort and/or time. I'm thinking of using Tobler's Hiking Function for my analysis. How can I confirm that the OS dataset already accounts for this? I'm not sure if this is specifically calibrated for walking or just a general slope cost, regardless of the mode. I see the QNEAT3 has speed field and topology tolerance options, but I'm unsure if I need to mess with those to get what I'm after. Any insights or tips would be super helpful!
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Slope cost in mapping pedestrian iso-areas
- Thread starter Jill.GIS
- Start date
PhillyPride
New member
- Joined
- May 23, 2025
- Messages
- 4
for hilly areas, I don't think OS data typically apply a specific Tobler like slope cost internally for pedestrians. You'll almost certainly need to factor it in yourself.I'm trying to generate 15-minute pedestrian walking iso-areas from various points using QNEAT3 and the OS multi-modal routing network. The area is hilly and I want my map to accurately capture how walking uphill and downhill take more or less effort and/or time. I'm thinking of using Tobler's Hiking Function for my analysis. How can I confirm that the OS dataset already accounts for this? I'm not sure if this is specifically calibrated for walking or just a general slope cost, regardless of the mode. I see the QNEAT3 has speed field and topology tolerance options, but I'm unsure if I need to mess with those to get what I'm after. Any insights or tips would be super helpful!
Here's what you should do:
DEM: Get elevation data.
Calculate Slope: Derive slope (gradient/degrees) for each network segment.
Field Calculator: Apply your chosen Tobler's formula to each segment's length and slope to get a new travel_time or speed attribute.
QNEAT3: Use that new field as your Speed Field. Set your iso area time in seconds.
The topology tolerance is for network connectivity, not slope
The OS network doesn't factor in hills for walking, it just uses flat speeds. If you want slope aware isochrones you'll need to bring in a DEM, calculate slope along edges, and apply something like Tobler's hiking function yourself, then feed those times into QNEAT3.I'm trying to generate 15-minute pedestrian walking iso-areas from various points using QNEAT3 and the OS multi-modal routing network. The area is hilly and I want my map to accurately capture how walking uphill and downhill take more or less effort and/or time. I'm thinking of using Tobler's Hiking Function for my analysis. How can I confirm that the OS dataset already accounts for this? I'm not sure if this is specifically calibrated for walking or just a general slope cost, regardless of the mode. I see the QNEAT3 has speed field and topology tolerance options, but I'm unsure if I need to mess with those to get what I'm after. Any insights or tips would be super helpful!