Shapefile saving to unknown format instead of geojson

Question

I have a shapefile and would like to export a single record (polygon), which I've selected, to GeoJSON.

I have never had a problem with this before. I've checked the CRS - it is defined as ESPG: 4326. I choose Save As... > Tick "only selected features" but then I am given an unknown table instead of a GeoJSON file.

Why might this be happening?

Here is a link to the shapefile in question: link

Answer 1

Le me summarize our findings and unknowns ("as is" basis).

[What we found]

• Format conversion of a Vector layer to GeoJSON through "Save As..." function creates a Table layer without geometries, with a distinctive suffix Unknown when it appears on Layers Panel.
• This happens when the GeoJSON could not take geometry information from its original layer, for instance:
  • User choose not to save its geometry, by selecting 'No geometry' at the Geometry | Geometry type section, or
  • The original layer (or selected feature) had geometry error(s).

[Unknown]

• Root cause and where was the error.
• Some vector operations which access its geometry had rectified the error, but the reason why they had been successful was not clear.

Happy to update and edit further.