Simple question.
I have read and heard so many times that the political borders between kingdoms during the middle ages (whether it's high or late) were very blurry. People had a general idea of regions being under control of one kingdom or lord but it was not a clear precise border like it was depicted on maps.
Them, if that is the case, why is it that every single map I've seen that represent the political reality of medieval Europe has clear cragged borders?
I think my question can apply to maps from the high or late middles as well as northern, western of eastern Europe. But for the sake of rules, if needs be, we can focus on Western Europe maps for the period of 13th to 15th century.
I'm going to assume you're talking about modern maps depicting medieval Europe, rather than maps produced in the Middle Ages, which didn't include political borders at all (at least not in surviving maps).
The answer is perhaps simple, but it's because it's much easier to draw linear borders and to represent them in a neat way visually than to have the majority of the map coloured in as some sort of liminal frontier zone, which would have been constantly shifting. Political maps of medieval Europe are necessary abstractions and generalisations, like historians make all the time, which should be seen as outlining spheres of influence rather than solid borders. Most good history survey books and historical atlases will point this out.