Does your minecraft map on 360 transfer to Xbox one?

I'm thinking about buying minecraft again. I have a PS4 and a Xbox one. I would buy the One version if it keeps my maps but if it doesn't then what would be the point but to just buy it on my PS4.

I'm sorry to report that the XBox 360 & PS4 versions of NOT COMPATIBLE with the XBox One version.

The Xbox 360 version ran it's own platform-specific version, which was discontinued after the release of the Update Aquatic (Java version 1.13). Mojang never released the Bedrock Engine version for the console (mostly dedicating resources for the XBox One & Windows 10 support of the engine). Additionally, there's NO WORLD EXPORT OPTIONS… So your world is stuck on the 360.

The PS4 is currently running it's own Legacy Console version, which operates separately from the Bedrock Engine & still being updated. The main reason why it's NOT running on the Bedrock Engine that Sony has not granted Cross-Platform permission for Minecraft (which Fortnite & Rocket League have obtained). Once Sony grants Cross-Platform support, it'll get rolled into the Bedrock Engine version.

The XBox One, as mentioned above, is running on the Bedrock Engine alongside the Switch, Windows 10 & Mobile versions. At this time, ONLY the Windows 10 version has world import & export support… Which is helpful to move an offline world onto a Bedrock Engine Dedicated (BED) server for Windows 10 & mobile (XBox One & Switch can't connect to privately-operated servers via an IP address at this time). The one practical upshot is that once you're on the Bedrock Engine, it becomes easier to move world data between different platforms as they're all utilizing the same data.

This is just my 2+ KB here, but I hope it sheds light on the subject.