BeRKA asked in a what I thought about the issue of dangling routes - routes depicted as leading from a sector to a neighboring sector, but with no appropriate target in the accepted data for the target sector. One option is to treat certain maps (e.g. Spinward Marches) as canonical down to the angle of the departing route and try and fix the data in the target sector. Another is to fix the angle of the departing route so that it lands on a documented world. BeRKA likes the second approach.
I agree with changing the angle, and preserving the route if possible. My philosophy is that you should respect the intent and knowledge of the creators of a map, and to assume that other cartographers had/have this philosophy as well, to within the limits of the resources and time available.
When the Spinward Marches map was created, nothing was documented about nearby sectors. Therefore, the intent was that there was an outgoing route, but the target was guesswork.
The next big data set was the Atlas of the Imperium, which is lacking routes altogether. From that, I assume that the level of detail wasn't considered. Possibly, the scope of matching the routes was outside the time available. Alternately, the data may have been generated in such a way (e.g. seeded random numbers) that tweaking the data was unpalatable. Finally, going back to the intent of the Spinward Marches map creator, the outgoing routes could be considered as "guesswork" only, and up to later revision.
Another reason for inconsistencies is that the earlier data simply wasn't available. While everyone must have had access to the Spinward Marches map, as you get farther away from GDW and DGP as sources you can't assume the resources were available to everyone. Time also takes its toll - tracking down DGP resources is very time consuming now. Ask MJD how he tackled the Gateway sector!
So anyway: when I run into a dangling route I try to match it up as best I can, preserving the source and the target angle if possible.
Also, regarding DGP data, the Travellers' Digest "Grand Tour" Adventure followed a definite path around Charted Space: Deneb, Corridor, Vland, Lishun, Core, Massilia, Old Expanses, Solomani Rim, Magyar, Daibei, Reaver's Deep, Dark Nebula, Ealiyasiyw, Riftspan Reaches, Trojan Reach, Spinward Marches. This gives you a precedence order and can explain some inconsistencies - for example Magyar was probably charted several months before Dark Nebula, so Magyar may be missing some routes implied by Dark Nebula.