According to the GeoJSON specification [1]:
> * A linear ring is a closed LineString with four or more positions.
> * The first and last positions are equivalent, and they MUST contain
> identical values; their representation SHOULD also be identical.
> (...)
> * For type "Polygon", the "coordinates" member MUST be an array of
> linear ring coordinate arrays.
Note that, for simplicity, right now we aren't checking whether the
coordinates are defined counterclockwise for exterior rings and
clockwise for interior rings, which is what the specification expects.
[1] https://datatracker.ietf.org/doc/html/rfc7946#section-3.1.6
We're reworking the format validation to correctly interpret feature
collection, feature, and geometry, according to RFC 7946 [1].
Since Leaflet interprets GeoJSON format, we're rendering the GeoJSON as
a layer instead of as a set of points. For that, we're normalizing the
GeoJSON to make sure it contains either a Feature or a
FeatureCollection. We're also adding the Leaflet images to the assets
path so the markers used for point geometries are rendered correctly.
Note we no longer allow a GeoJSON containing a geometry but not a
defined type. Since there might be invalid GeoJSON in existing Consul
Democracy databases, we're normalizing these existing geometry objects
to be part of a feature object.
We're also wrapping the outline points in a FeatureCollection object
because most of the large GIS systems eg ArcGIS, QGIS export geojson as
a complete FeatureCollection.
[1] https://datatracker.ietf.org/doc/html/rfc7946
Co-authored-by: Javi Martín <javim@elretirao.net>
