The location of various genes on a chromosome relative to specific microscopically visible landmark on the chromosome is called

The location of various genes on a chromosome relative to specific microscopically visible landmarks on the chromosome is called a Cytogenetic map.
A cytogenetic map is the visual appearance of a chromosome when stained and examined under a microscope. Particularly important are visually distinct regions, called light and dark bands, which give each of the chromosomes a unique appearance.