JSON-FG Draft Standard

[docuracy]

@kgeographer has drawn our attention to the OGC draft standard for JSON-FG (features and geometry) here, which proposes adding a simple time element to GeoJSON (among other things).

The proposals are defined here in JSON Schema format.

Observations

1. JSON-FG features are required to have ALL of ["type", "time", "place", "geometry", "properties"], which seems to me unnecessarily verbose.
2. The time object is limited to a more restricted set of ISO 8601 expressions than is permitted in the current LPF (though these are not defined/enforced by any regex patterns in the JSON Schema).
3. The time object neatly uses ISO 8601-2 '..' notation to express unbounded intervals, but offers no means to represent after/before or earliest/latest.
4. The link object described here is quite different from an LPF link. It uses href instead of identifier, and includes optional properties that might be considered useful for LPF.
5. The representation of intervals as strings was rejected because a JSON structure 'is easier to parse' (see here), which seems to me a lazy and unnecessary concession to programmers at the expense of non-technical users. Parsing a string and splitting it on a '/' is trivial.

Suggestions

1. LPF should adopt the OGC restricted set of ISO 8601 expressions for date and datetime.
2. LPF links should conform to the OGC standard.
3. LPF should keep its when property to avoid confusion with the OGC time property (which is both inadequate and over-prescriptive for LPF purposes).