Why do you think the mentioned "color-centric" image processing operations deserve a specialized file format, rather than building and using a transient index in memory when it is useful? Do you have some special use case in mind?
Any interactive application, for instance, can be expected to render the image to the screen (repeatedly); any GPU use for texture mapping needs pixels sorted by location, regardless of whether pixel values are palette indices or explicit colours; many image processing tasks, like segmentation and drawing, need efficient access to pixels at arbitrary locations or near already processed locations.
The technique actually supports both modes in the implementation (synthetic skeleton or random subsampling). However, for this browser visualisation, we default to the synthetic sine skeleton for two reasons:
1. Determinism: Random landmarks produce a different layout every time you calculate the projection. For a user interface, we needed the layout to be identical every time the user loads the data, without needing to cache a random seed. 2. Topology Forcing: By using a fixed sine/loop skeleton, we implicitly 'unroll' the high-dimensional data onto a clean reduced structure. We found this easier for users to visually navigate compared to the unpredictable geometry that comes from a random subset