Focus-Glue-Context Fisheye Transformations for Spatial Visualization

Focus-glue-context (FGC) fisheye transformations to two-dimensional coordinates and spatial vector geometries. Implements a smooth radial distortion that enlarges a focal region, transitions through a glue ring, and preserves outside context. Methods build on generalized fisheye views and focus+context mapping. For more details see Furnas (1986) , Furnas (2006) and Yamamoto et al. (2009) .