The dim: parameter defines the diameter of a viewing circle centered on the coordinate. While the default unit of measurement is metres, the km suffix may be appended to indicate kilometres.

GeoHack uses dim: to select a map scale such that the viewing circle appears roughly 10 centimetres (4 in) in diameter on a 72 dpi computer monitor. If no dim:, type:, or scale: parameters are provided, GeoHack uses its default viewing circle of 30 kilometres (19 mi).

Samples
Subject View diameter Markup Result
Western Hemisphere 10 000 kilometres (6 200 mi) {{coord|0|N|90|W|dim:10000km}} 0° с. ш. 90° з. д.HGЯO
Ohio 400 kilometres (250 mi) {{coord|40.5|-82.5|dim:400km}} 40°30′ с. ш. 82°30′ з. д.HGЯO
Dresden 20 000 metres (12 mi) {{coord|51.033|13.73|dim:20000}} 51°01′59″ с. ш. 13°43′48″ в. д.HGЯO
Statue of Liberty 100 metres (330 ft) {{coord|40.6892|-74.0445|dim:100}} 40°41′21″ с. ш. 74°02′40″ з. д.HGЯO