Support for Geospatial Geometries

[yeesian]

Hi, so I've started out defining some of my own types (e.g. in GeoJSON.jl), mainly

• Points (both 2 and 3D)
• MultiPoints (a vector of points)
• LineStrings (a vector of points),
• Polygons (a vector of LinearRings[1]), and
• Multi-* (a vector of *; where * can stand for any of Point/LineString/Polygon)

with the itch to generalize them through GeoInterface.jl to support geometries across Shapefile.jl, LibGEOS.jl, and Geodesy.jl. Among other things, it provides a small set of conversion routines to their Compose.jl counterparts here (while awaiting the verdict on issues like rohitvarkey/Compose3D.jl#2)

They have a fairly consistent set of semantics (spelt out across different specifications [2,3,4,5]) with common operations [6] defined on them, partially implemented through experiments in

• Turf.jl which operates on native Julian objects, and
• LibGEOS.jl which operates on wrappers to opaque C objects.

But going forward, for future interoperability, I'd be happy for that responsibility to rest within JuliaGeometry instead. Might you consider providing types for some of the common geometries for Geospatial applications in this repository?

[1]: LinearRings are LineStrings, with matching first and last coordinates
[2]: John R. Herring, Ed., “OpenGIS Implementation Specification for Geographic information - Simple feature access - Part 1: Common architecture,” Oct. 2006.
[3]: Martin Davis, “JTS Technical Specifications,” Mar. 2003. [PDF]
[4]: The GeoJSON Format Specification [link]
[5]: ESRI Shapefile Technical Description [PDF]
[6]: E. Clementini, P. Di Felice, and P. van Oosterom, “A Small Set of Formal Topological Relationships Suitable for End-User Interaction,” Third International Symposium on Large Spatial Databases (SSD). Lecture Notes in Computer Science no. 692, David Abel and Beng Chin Ooi, Eds., Singapore: Springer Verlag, 1993, pp. 277-295. [PDF]

[SimonDanisch]

Yes! Would be great to have them here.
Right now I'm pretty tight with time, but in the long term I want to do everything possible to create a unified, pleasant to use platform for handling geometry.
So don't expect it to move fast from my side, but any pull requests and issues with a finer granularity are more than welcome!
If you're unsure how to procede, please consider discussing stuff via pullrequests in meta, or via the gitter chat (badge is in the meta readme).
CC: @sjkelly , @shashi, @rohitvarkey, @KristofferC

Best,
Simon