Mapping a specific region in matlab with high-detail coastlines

Hello,

I recently discovered matlab is capable of mapping places of the world using the mapping toolbox. However, I found out that the default coastlines are rather lacking in detail. I understand that, in order to achieve more detail, I should download a higher resolution dataset of the coastlines and import it into matlab. I am new to this toolbox so I am unsure how to do that.

Simply put, what I want is this;

1) A map of the Gulf of Genoa, with high detail coastlines. Country borders are not necessary.

2) Arrows pointing towards a specific coordinate, at a specific angle. Optional and not necessary.

I found an example of this online, of the North Sea. I believe it is also made using matlab.

Can someone run me through the process of downloading high-resolution coastline data, importing these into matlab, and mapping a specific region?

Thanks in advance.