Since version 1.4, Cartographica has contained a highly-useful, but somewhat hidden feature for navigation called Bookmarks. In Cartographica, these contain both a geospatial location (in latitude and longitude, so that they can be converted agnostically into any CRS) and a scale in meters.
Bookmarks can be created manually through the UberBrowser panel using the Bookmarks tab, or can be saved from any map by choosing View > Bookmark Extent. When saved, the new bookmark will have the location and scale of the current Map Window, and when manually created, you will have the opportunity to input the coordinates and scale manually.
Bookmarks are stored in your Preferences, so they can be used in with any map; making them a great tool for locating either the same place on multiple maps or just as a temporary way to look at the same place on two different maps.