This tool will let you browse the Final Fantasy IV universe with a simple point-and-click interface.
The map viewer currently operates in a fashion similiar to other online map sites. If the map is larger than the window, you can click and drag to move the map. In addition, you can also zoom in or out using your mouse scroll wheel. I haven't tested it on mobile, and I don't expect it to work very well at this time.
By default, the map shows a tile overlay which indicates interesting tiles with the following colors:
Any extra information about the tile will appear to the right of the map when you hover over the tile. If the tile is a warp of some sort, clicking on the tile will take you to the appropriate map. (Warps will take you to the designated map. Return warps will take you back to the last map you visited.)
Some maps don't have any way to exit, since they rely on you being able to reach the edge of the map (which works the same as a return warp, if the border is crossable). In such cases, simply press the green button above to simulate a return.
Finally, you can directly go to certain locations via the toolbar above.