dabreegster
commented
1 week ago See #22 and #4. I think generating the graph from vector tiles is a cool idea, because it could potentially shrink the bandwidth/storage requirements. What scale does this offline map cover?
Complications:
- vector tiles don't encode a graph, so when tunnels/bridges cross, this would incorrectly become routable
- the route snapper assumes a fixed graph; there's no tiling. So you could try feeding in all the roads from the entire pmtiles file, or rebuild constantly based on what's in the viewport. If you're doing the former, then... it might be much simpler to just build the graph file once, if the file size difference isn't bad.
Valhalla has routable tiles and is optimized for embedded environments, I think: https://valhalla.github.io/valhalla/tiles/
I think some of the folks involved in https://github.com/maplibre/maplibre-tile-spec are also interested in a tile format that could support both rendering and routing. I've seen some discussion in https://slack.openstreetmap.us/ in a channel for maplibre tiles
I could maybe help with this.
I would like to have offline maps and directions. The offline maps I intend on solving by using .pmtiles and a service worker that simulates the range request. I am wondering if the .pmtiles can also be used to generate the graph on the fly. It has all the vector tiles. In ym use case the end users device has the whole .pmtiles.