Rutter

A rutter is a navigational chart of subspace, especially for the regions in the Wilds which are not marked by gravity anchored subspace beacons. Even in the Midlands it is common for a world or confederation or empire of worlds to post a subspace beacon in an area of subspace which gives access to their system. Of course even in the Midlands there are worlds which chose to remain hidden, or at least to make outside navigation difficult.
In the Wilds many groups deliberately seek to hide their presence, or at least attempt to remain unknown to all but their friends. Others simply do not have the capability to maintain a subspace beacon.
In the absence of a beacon a ship traveling subspace must rely on inertial navigation and gravitational topology plotting, a very dangerous prospect, especially when there is not a supporting structure like the Highland's Department of Roads gravitational sensors and storm warnings to allow advanced notice of moving gravitational shear planes, i.e. susbspace storms. A rutter is a record of the path taken by another vessel which gives lapsed time, inertial navigational data and gravity plots of areas of subspace which are not marked with beacons. It is basically a set of data that can be loaded into the navigational computer system of a vessel that will allow that vessel to follow the course of the ship that recorded the rutter.
Most rutters are not public knowledge, but are instead carefully guarded proprietary secrets of traders or merchants. Often explorers will attempt to cash in on the strength of their rutters. The Church attempts to collect sets of rutters which they will often publish in an attempt to open up a region, though not always immediately, sometimes delaying use to themselves for reasons of limiting exploitation of degraded cultures.