• The OP mentions the “dataset” is composed of maps they created and those works would be copyrightable if they wanted. Additionally the arrangement of the works and composition of the works in the dataset might also be copyrightable.
• licensing extends beyond copyrights and clarifies terms of use to protect both creator and users even when copyrightability might be debatable in some jurisdictions.

Sounds pretty neat. Licensing can be pretty complex but MIT is a pretty much no-frills license that let’s them do with your dataset what they want. CC0 (public domain) is similar.

Alternatively you can also use something like CC-BY license which also let’s people use it but it requires attribution.

A step beyond that is the CC-BY-SA which is similar but requires anything new created with the data to be licensed under the same license (share alike).

Just depends on what you want to do, and what you want people to do when they use your data. Id recommend MIT, CC0, or the CC-BY-4.0 license since these ensure the most people can use it if that’s your goal