They are presets for the advanced settings. The advanced settings are Starting town, Starting units, Starting distance, Roads, Roaming units, Treasures, Cities, Dwellings, Resource structures, Visit structures, Treasure structures. Starting town is the size of your town from none, to settler, all the way to Metropolis. Starting units goes from weak to battle and I don't know exactly what it entails. Starting distances are close where your next to everyone else, Average where while you are not next to each other you won't be placed in the corners, and far which basically places you at the edge of the map and if you have 4 players your probably each in a corner. Roads go from none to many and are what can determine exploration speed. Roaming units is also none to many and this will be the structures that produce them. Treasures go from minimum to many and are the random piles of gold and what not you find, be warned if you use a lot then early game exploring is extra important and can make a multiplayer game unfair. Cities go from none to many, the same goes form Dwellings, Resource structures, Visit structures, and Treasure structures. The modes are:
Normal
Village
Medium units
Average distance, roads, roaming units, treasures, cities, dwellings, resource structures, visit structures, and treasure structures
Battle
Metropolis
Battle level starting units
Near distance
Many roads ands cities
Average roaming units, treasures, dwellings, and visit structures
Few resource structures and treasure structures
Empire Building
Settler
Medium units
Far distance
No roads and Cities
Average roaming units, treasures, visit structures, and treasure structures
Many resource structures
Few dwellings
Adventure
No starting town or settler
Strong units
random distance
Average roads, roaming units, and visit structures
Many treasures, Dwelings, and treasure structures
Few cities and resource structures
If you want to know more about the random map generation settings then I advise iHunterKiller's one video though overall I advise his videos to learn the game period. Anyway here is a link to where he starts talking about the map creation stuff:
http://youtu.be/hTKwI3N-kuU?t=13m13s