Examples of problematic geometries

[jakepruitt]

Beginning a running list of problematic geometries from other mapnik and earcut-related projects. Going to be adding to this list as I see more tickets appears.

• Null island (Point at null island leads to "Error calculating min/max zoom: Bounds invalid" mapbox/mapnik-omnivore#88)
• US States Shapefiles (https://github.com/mapbox/mapnik-test-data/tree/master/data/shp/us_states)
• Martian coordinates (Omnivore fails hard on martian coordinate systems mapbox/mapnik-omnivore#124)

Please add any other problematic edge cases you are aware of, if you have time, @rclark, @springmeyer @flippmoke @GretaCB

[wilhelmberg]

us_states.shp works for me:

• QGIS reports no geometry errors (just two vertices at the same location)
• MBS Classic 0.3.1. from x64 installer displays fine
• upload to Mapbox also no problem:
  https://api.mapbox.com/v4/lr1k.c0ef5c13/page.html?access_token=pk.eyJ1IjoibHIxayIsImEiOiJ0ZDVoZ2FVIn0.VvDeZC2BzGINcCxObpfesw#4/1.05/-80.55

[GretaCB]

@BergWerkGIS Interesting. This is super odd. I tried re-uploading and navigated my map to the same z/x/y where your map ^^ displays the data, and I get partial tiling:

http://api.mapbox.com/v4/carolbhansen.us-states-test/page.html?access_token=pk.eyJ1IjoiY2Fyb2xiaGFuc2VuIiwiYSI6Iko1a0xjODgifQ.h7f9foFVduSgzGrh06hKUw#5/43.660/-95.208

• My link above is the zipped version of us_states from mapnik-test-data.
• I just tried us_states.shp from https://github.com/mapbox/mapnik-test-data/tree/master/data/shp/

Looks like us_states.zip is different than us_states.shp.

[wilhelmberg]

ahhh, I used
https://github.com/mapbox/mapnik-test-data/tree/master/data/shp/us_states

Looks like us_states.zip is different than us_states.shp.

Yes you are right, zip just contains DC:

But it is there, even in your upload:
http://api.mapbox.com/v4/carolbhansen.us-states-test/page.html?access_token=pk.eyJ1IjoiY2Fyb2xiaGFuc2VuIiwiYSI6Iko1a0xjODgifQ.h7f9foFVduSgzGrh06hKUw#7/38.895/-77.014
It's not easy to spot, because the zoom level is limited to 7.

Maybe the automatic zoom level detection has to be given another thought?
Where does this happen, mapnik-omnivore?

I uploaded us_states.zip via Mapbox Studio and made it available up to 16:
https://api.mapbox.com/v4/lr1k.2b97dd4d/page.html?access_token=pk.eyJ1IjoibHIxayIsImEiOiJ0ZDVoZ2FVIn0.VvDeZC2BzGINcCxObpfesw#12/38.8877/-77.0275

[mapsam]

Found one today where we had a GeoJSON file with a leading byte character that failed in mapnik tests. This PR removed the character, but might be worth keeping the old file for failed tests?