Raster support

[elphick]

I'm looking for the most efficient way to store a raster in an OMF2 file. Consider this workflow:

1. Create a RegularBlockModel
2. Source elevation and imagery rasters with the same extents and the pixel size aligning with the block model block_size in x-y.
3. Create a RegularGridSurface and store the elevation data as an attribute, and store the imagery as a texture.

I cannot find an appropriate object, such as RegularGridSurface to support this workflow. There is only Surface (triangulations) and TensorGridSurface.

While it is possible to store the raster using a TensorGridSurface, this is not ideal (in this case) for two reasons:

1. It is less compact,
2. The grid no longer equivalent to the block model grid (in x-y)

I'm led to believe the omf-rust project is leading the charge in relation to the OMF2 specification, and that describes a regular 2D grid here.

Is this a gap, or have I missed something?