That is quite possible, I posted it for the Slavic forms which are not at all universal and differ even within the West Slavic branch. Old Czech also did not have one universal "ano" and "ne".
German uses doch for some answers instead of ja.
The map is also dubious in the division of Lowland and Highland Scotland, I'd expect it to be the opposite.
There is no "da" in Czech. But despite of geographical distance there are some similarities.
It doesn't flat out mean yes (for that there is "ano"), but it can. As kacenka9 wrote, it depends on the context. When "tak" is used in czech as a yes, it has a sense of confirming something. For example when you finally start to understand something you didn't understand before and you repeat it to someone, they can shortly confirm if you're right by saing "tak". It's common to even say "taktak".