The Customized Metric Grid Reference Window Facility provides rectangular windows of various sizes and shapes through which restricted areas of the globe can be viewed and locations within those areas can be addressed by means of truncated addresses. The boundaries of the rectangles are metric grid lines which serve as boundaries of SQUARES or DOMAINS. The two smallest window sizes are the SQUARE and the single DOMAIN; all other windows comprise sets of DOMAINS, up to and including the entire globe. It is to be noted that latitude lines and even the very concept of latitude play no role in the Customized Metric Grid Reference Window Facility since it is my observation and considered opinion that the concept of latitude is antithetical to good metric gridding.

The Customized Metric Grid Reference Window Facility supports 5 different sizes of Reference Window through which restricted areas of the globe may be viewed, and corresponding forms of truncated addresses for locations within those restricted areas. Here, the term truncated address means high-order or left-end truncation, which clearly has the effect of limiting the area throughout which the address remains valid without having any effect on the precision or resolution of the address. All character-lengths of truncated addresses are quoted for 1-meter resolution addresses. In practice, of course, low-order or right-end truncations are regularly used when shorter addresses are desired and reduced precision is tolerable or desirable, but we do not here consider such low-order truncations.

An associated display shows clearly that MGRW Case #2 windows can provide a separation between homonymous neighbors (repeats) of truncated addresses which is twice as great as that provided by MGRS. The yellow RECTANGLES on the left denote the DOMAINS containing repeats of the MGRS truncated address for South Astro, while the yellow RECTANGLES on the right denote the DOMAINS containing repeats of the MGRW Case #2 truncated address for the city of Kabul in Afghanistan.