Add interpretAs and withNoData methods to Tile - #1702

Is this WIP until the RFC gets worked out?

I'd be happy to bundle them together, but they don't have to be. This PR can be merged as is and addresses the issue that spawned it.

@lossyrob @moradology Ready for review again after .withNoData changes.

One final through is that what is currently .interpretAs might be better named .withCellType. That name seems consistent with behavior:

• If we're not changing underlying data type this just re-wraps the array with new CellType.
• Otherwise we coerce to the desired cell type and label it with new NoDataHandling

@echeipesh I think withCellType is a bit ambiguous, and might be read as doing the same thing convert does. But I've though about this less, so if you are strong +1 on that name I'll follow your lead.

I also think withCellType seems more ambiguous. Have we considered, as an alternative to interpretAs, reinterpret? The other reason I like interpret is that it makes clear that we're dealing with something which quite likely modifies the Tile's semantics (making its numbers mean different things on the output than they meant prior to the method having been called).

I prefer interpretAs to reinterpret. I thought that withCellType has nice symmetry to withNoData but lets discount it since its got two votes against it. I'm still not totally happy with interpretAs, I'd like to capture the intuition is that this is equivalent of calling _.toDouble or _.toInt on cell by cell basis.

• toCellType(IntCells)
• asCellType(IntCells)
• convertRaw(IntCells)
• convertFromRaw(IntCells)
• reassign(IntCells)
• coerce(IntCells)

Semantic ambiguity could be addressed in docstrings.

+1 interpretAs. I think it's the most semantically clear.

I like the word coercion but it usually means an implicit type conversion the word cast used for explicit (correct me if I'm wrong). So probably interpretAs or even cast (but cast looks similar to convert). But I see no problems with withCellType name as well, as for me it means more a type interpretation rather than conversion :))

• +1 interpretAs

Thank you everybody for chiming in on the naming!
For eons let it written, let it be said: Tile.interpretAs