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cevi / automatic_walk-time_tables

Automatically creates a walk-time table from an exported track from Swisstopo-App, SchweizMobil, or from an arbitrary GPX-file
http://map.cevi.tools
GNU Affero General Public License v3.0
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Height Altitude Bridges lead to Massive Errors in Marschzeittabelle #69

Open wp99cp opened 2 years ago

wp99cp commented 2 years ago

Consider a route traversing a height altitude bridge, for example, the Tamina-Schlucht bridge (route attached as KML and GPX).

Screenshot from 2022-04-26 13-25-48

If this route gets exported as a KML file we fetch the terrain height data over the Swisstopo API (as KML files do not always include elevation data). The Swisstopo API returns terrain height and not street-level height info, therefore this results in a massive error in the walk time estimation. As can be clearly seen in the elevation profile:

KML file (left) vs GPX file (right)

Screenshot from 2022-04-26 13-34-22

KML_File.zip

maede97 commented 5 months ago

This issue still exists even with Valhalla as the new (dev) routing engine: image