Feature request: spatial form widget

[florianm]

Cross post from ckanext-scheming.

Our CKAN users love the dataset extent map to bits, but regularly despair on providing valid GeoJSON geometries. Drawing polygons on a Leaflet map, or uploading a GeoJSON file is basically where it ends for them.

It would be ideal if the "spatial" field would allow the user to either

• paste a valid geojson geometry as usual, or
• let users select geometries from a list of custom geometries (e.g. administrative boundaries like marine parks), or
• draw a polygon on a leaflet map, writing back the geojson geometry of the convex hull (if several polygons are drawn) or
• upload a geojson file with the bounding polygon (or a bunch of features), then calculate the convex hull post-upload.

If we can edit "spatial" inline, it would be most logical to display the Dataset extent map also inline, replacing the unreadable WKT - that's easy enough, see my poc.