Provide Geo Interface for Collection and Records

[kannes]

This is a feature request, not a bug report.

Please provide the __geo_interface__ property for both the whole Collection (mirroring GeoPandas approach of returning something like a GeoJSON FeatureCollection) and for each Record (like a GeoJSON Feature).

This would add Fiona to the fabulous list of projects supporting the Geo Interface and it would make plotting in Altair (thanks to the recent addition of vega/altair#1664) super duper easy.

✌️🥳🎉

[sgillies]

We'll do this for features, but not for collections, which can be very large. Handling that situation is best left up to the fiona user.

[kannes]

Do you worry about memory issues or is there another reason that this could be problematic?

@mattijn Would features be enough for Altair support?

[mattijn]

A fiona.Collection is a Iterator, so the features are parsed one by one. For __geo_interface__ support you’ll have to return all features in once as a copy. That is a choice.

Currently a single fiona feature is just a plain dictionary. I don’t know many people who uses fiona that like to plot a single feature. So that is probably not so useful. To collect the features of interest in a list won’t help much since a plain list has no __geo_interface__.

So you’ll still need to create a FeatureCollection by yourself: geojson.FeatureCollection(list(fio_col))

[sgillies]

Still tracking this for 1.9.0.

[sgillies]

Geo interface for Feature is done. I've decided not to do anything about Collection. Very large feature collection blobs are, from this project's perspective, an anti-pattern. Fiona is more about streaming features. And as pointed out, it's only 1-2 lines of code to materialize a Collection.

[kannes]

you

[sgillies]

Done!