Space Maps visualization of 1,000 genes with 5,372 samples. (A) An expression profile at five levels of the hierarchy. Level L1 corresponds to the root and Level L5 corresponds to the leafs of the hierarchy. The information-content of the glyph increases as the levels increase. (B) A non-linear projection  of 1,000 expression profiles into 2D space. It is possible to make out global patterns such as clusters and outliers. Local patterns in the expression profiles can be identified as well, for instance in the lower left corner.