2/ The map of Iberia "only" plots the different regional languages, it doesn’t convey anything regarding language characteristics.
So it is simply a “map of languages” rather than a “linguistic map”.
We’re interested in the other two, which are great examples of linguistic maps which plot lexical (words) and syntactic (sentence structure) variation across geographical space.
3/ Now for a quick crash course in linguistics:
There are many branches, but for today, it’ll be helpful to understand the following in a bit more detail:
• Dialectology - the study of subsets of language (dialects) ex: Scouse English, Bavarian German
• Phonetics - the study of sounds of speech - cat vs chat, ik vs ich
• Sociolinguistics - the study of how social factors (i.e. age, class) impact speech
These, of course, are not official definitions of these terms!