Catch more invalid files with verify command about go-pmtiles

[bdon]

Can you try generating the file with a minimal PNG image, hardcoded bytes, and inspecting in the viewer?

The verify command is meant for verifying the container organization, and not the tile contents, so it is difficult to distinguish between the read failure being the container or the individual contents...

[dabreegster]

The container bit was just fine; the bug was in not getting coordinate transforms right at all in the MVT part. Stuart got a minimal working example in Urban-Analytics-Technology-Platform/od2net#40.

Maybe what could be useful is something to verify MVT contents or better error messages, but I think the Uncaught Error: unknown command 4 is auto-generated protobuffer code anyway.

Thanks!

[bdon]

Here's a related issue of improving error messages in maplibre for malformed PBFs:

maplibre/maplibre-gl-js#2809

My thinking right now is that verifying individual MVTs takes this project too far - a verify on a planet basemap would need to spend a lot more time parsing 100+ million tile contents, unless we make it optional (adding more complexity...)

[dabreegster]

For the record, figured this out: Urban-Analytics-Technology-Platform/od2net@f7bfb02
There's a bug in https://crates.io/crates/mvt where asking to encode a LineString with 0 points doesn't fail as it should, but instead writes something invalid. Will be fixing upstream.

And I hope to have a working demo soon of a tippecanoe alternative specialized for a particular LineString case!