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More precise elevation data for GraphHopper routing engine

graphhopper.com

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Re: More precise elevation data for GraphHopper routing engine

#6

Post by sarnu »

oflebbe wrote: post #5

I am really looking forward for using better elevation data. So important for bike planning.

Yes, agree. Some services (e.g. komoot) apparently have good data, or can work around it. Others are struggling with lack of precision in the DEM data. As much as I like the tweakability of BRouter, the tracks generated never give realistic elevation info.

Re: More precise elevation data for GraphHopper routing engine

#7

Post by jtbaker »

NoahZuniga wrote: post #3

Or, how we downloaded open data from one source into our system.

our open source system. We use this tool to serve a custom routing engine at day job. Handles 100req/s djikstra in a 2GB pod, due to precalculation of contraction hierarchies.

Re: More precise elevation data for GraphHopper routing engine

#8

Post by jeffbee »

bloudermilk wrote: post #2

The DEM provider they integrated, Mapterhorn, looks great at a cursory glance. They’ve managed to source and package a ton of the free high res elevation data into one dataset for easy consumption. https://mapterhorn.com/

It looks pretty odd in Oakland, California, where the elevated freeways pass through the city. I guess the DEM they are using for that place is based partially on aerial radar surveys, partially on ground surveys? That's my guess based on the way the local streets cross the elevated freeways.

Example: this DEM thinks there is a local discontinuity where a cyclist will ascend at +22% where this street crosses a buried freeway. https://graphhopper.com/maps/?point=37.80737%2C-122.279329&p...

Re: More precise elevation data for GraphHopper routing engine

#9

Post by jeffbee »

sarnu wrote: post #6
oflebbe wrote: post #5

I am really looking forward for using better elevation data. So important for bike planning.

Yes, agree. Some services (e.g. komoot) apparently have good data, or can work around it. Others are struggling with lack of precision in the DEM data. As much as I like the tweakability of BRouter, the tracks generated never give realistic elevation info.

Garmin and Strava must be sitting on a gold mine of practical DEM data based on ride and hike records. They have huge databases from mobile devices recording GPS position, speed, and pressure.

Re: More precise elevation data for GraphHopper routing engine

#10

Post by yorwba »

jeffbee wrote: post #8
bloudermilk wrote: post #2

The DEM provider they integrated, Mapterhorn, looks great at a cursory glance. They’ve managed to source and package a ton of the free high res elevation data into one dataset for easy consumption. https://mapterhorn.com/

It looks pretty odd in Oakland, California, where the elevated freeways pass through the city. I guess the DEM they are using for that place is based partially on aerial radar surveys, partially on ground surveys? That's my guess based on the way the local streets cross the elevated freeways. Example: this DEM thinks there is a local discontinuity where a cyclist will ascend at +22% where this street crosses a buried…

The Mapterhorn data for the area does have some obvious artifacts: https://mapterhorn.com/viewer/#map=16.15/37.806698/-122.2773...
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