[Geojson] Toward consensus on proposals

Martin Daly Martin.Daly at cadcorp.com
Wed Nov 2 08:04:34 PDT 2011


> We've got two proposals for changes to the spec and one that may be
> arriving (Andrew?), so it shouldn't take long to decide whether to
> accept them or not.
> 
> Circles and Ellipses:
> https://github.com/GeoJSONWG/geojson-
> spec/wiki/wiki/Proposal%20Circles%20and%20Ellipses%20Geoms
> 
> Let's be clear whether we're specifying paths or patches. Center
> coordinates + radius feels natural to me. If a CRS is defined,
> wouldn't it be best to apply those units to the radius? Otherwise,
> could we require units to always (MUST) be meters?
> 
> An ellipse is complicated by the two axes and their orientation.
> Defining these differently than GML does would need a strong argument.
> 
> Circles and ellipses can be approximated by polygons, but it becomes
> onerous for good approximations. I'm in favor of this proposal.

I'm in favour too, although I would prefer it to be circles only, as per OpenSearch Geo.

I think, while agreeing with Dale's point, that it *has* to use linear units for the radius: who has ever asked for coffee shops within a fraction of an arc second of here (to use the standard example)?

I'd be comfortable with either metres only, or the linear units of the CRS (coordinate units for projected, ellipsoid units for geographic). It is up to the software that is reading or writing the data to cope with converting to its own internal units.

> Data Series Proposal:
> https://github.com/GeoJSONWG/geojson-spec/wiki/Data-Series-Proposal
> 
> I'm concerned about adding something so specialized to the spec and
> also wonder why a data series object needs to be privileged instead of
> simply going in the properties object.

I agree that this looks too domain-specific for the core spec.

Martin

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