Q: What are digital maps?

Digital maps are offered as raster maps and vector maps.

Raster maps
Rasters maps are digital maps on the basis of individual pixels. Since each point must be represented on the map with a pixel and the colour, such maps require very much memory on the hard disk.
Examples for formats are GEOTIFF or BSB.

Vector maps
Vector maps are digital maps on basis of vectors. A line consists of 2 points, which are connected with each other. It requires less memory and therefore has a more simple zooming. Mostly it is possibly to switch to different layers and to fade out as well