Overzoom is the result of a tileset being zoomed in beyond its given zoom extent.

Raster tilesets will appear to lose clarity if overzoom occurs. For example, if you are displaying a raster tileset with a zoom extent between z0 and z6, if you zoom to a higher zoom level past z6, the imagery will become blurry and difficult to see.

The effects of overzoom are not as noticeable with vector tilesets since vector data is not stored in a pixel-based format, but rather encoded and calculated from a series of points, lines, and polygons. Because of this, vector data can be overzoomed and visualized to zoom 22.