Mapbox Vector Tile Unmarshal Failed: proto: wrong wireType = 7 for field Layers about orb

[wangyoucao577]

You're right. It works after use mvt.UnmarshalGzipped instead. Previously the .mvt comes from http works because the http.Get will silently uncompress the response if see Content-Encoding: gzip.

The .mvt comes from mapbox server is always gzipped, whatever with Accept-Encoding: gzip or not. I didn't see any explaination from mapbox document about the gzip. It looks like an implementation issue of mapbox's vector tile service.

[wangyoucao577]

I made a simple command line tool vt2geojson based on this library, which supports load mvt from either file or URL. The strange thing is it's ok to download from URL directly, but it reports this error from file, even from the file in encoding/mvt/testdata.

Please refer to the command line tool from: https://github.com/wangyoucao577/orb/tree/feature/vt2geojson/cmd/vt2geojson

$ cd cmd/vt2geojson
$ go build 
$ 
$ ./vt2geojson -mvt ../../encoding/mvt/testdata/15-8956-12223.mvt -summary
2020/02/03 15:52:51 proto: wrong wireType = 7 for field Layers

[invisiblefunnel]

I believe this failure is due to the data being gzipped. Try to gunzip the file or use mvt.UnmarshalGzipped.