Spatial analysis and filtering within polygons are impossible. Crude raster maps are considerably less beautiful than line maps Network linkages are difficult to establish Projection transformations are time consuming unless special algorithms or hardware is used. At most basic, simple file of coordinates as geocoded. Raster must build connected independent cells. Leads to fat lines, jaggies etc.
Alternative method is Freeman codes.
Often shorthand data are stored with chain, points only read in when required. Point based 2. Link based Quad Trees Two dimensional coding system, can be used for vectors and rasters.