Glyph-Based Multi-field Visualization - Scientific Visualization: Uncertainty, Multifield, Biomedical, and Scalable Visualization - page 128

However, it is not always easy to design a glyph-based visualization such that the
different data-to-property mappings are independent and do not influence each other
(the interpretation of shape details, for example, is usually influenced by the size of
the glyph). In this context, the number of data variates that can be depicted must be
seen in relation to the available screen resolution. Large and complex glyphs such as
the local probe [ 13 ] can be used when only a few data points need to be visualized. If
many glyphs should be displayed in a dense manner, however, a more simple glyph
may be desirable [ 10 ]. Another design guideline is the usage of redundancies ,for
instance, to use symmetries that ease the reconstruction of occluded parts of the
glyph. Important properties can, moreover, be mapped to multiple glyph properties
in order to reduce the risk of information loss.
Important aspects when rendering many glyphs in a dense 3D context are depth
perception, occlusion, and visual cluttering. In cases where many glyphs over-
lap, halos can help to enhance the depth perception and to distinguish individual
glyphs (compare to Piringer et al. [ 18 ]). For improving the depth perception for non-
overlapping glyphs a special color map (called chroma depth [ 23 ]) can be used to
represent depth. Finally, appropriate glyph placement [ 19 , 24 ], interactive slicing, or
filtering via brushing are strategies for dealing with occlusion and cluttering issues.
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