GeoJSON to SLF attribute conversion

[c0c0n3]

The location attribute gets stored as GeoJSON. When a client queries the attribute, QL returns GeoJSON. We discussed the possibility of having clients specify the format of the returned location value which could be either GeoJSON or NGSI SLF. This would work as follows:

1. Client specifies format through header or query param.
2. If specified format = GeoJSON, QL simply returns the content as is.
3. If specified format = SLF and stored location GeoJSON can be converted to SLF, QL converts the value on the fly before returning it.
4. If specified format = SLF and stored location GeoJSON cannot be converted to SLF, QL returns the GeoJSON content as is.

Note we need (4) since SLF only offers a subset of the geographical features supported by GeoJSON.

[github-actions]

Stale issue message

[daminichopra]

Hi @c0c0n3 @chicco785 , I would to investigate on this issue. Please assign. Also, if any reference related to NGSI SLF. Thank you !!

[c0c0n3]

Hi @daminichopra thanks for offering to work on this!

any reference related to NGSI SLF.

You should read the "Geospatial properties of entities" section of the v2 spec.

Also our SLF implementation comes w/ lots of Python docs and diagrams if memory serves, so you could have a look at that too if it helps.