Travel & Terrain

There are many different modes of travel in Ultima IV, some which are more efficient than others.
Walking
Normal mode of transportation.  Can encounter enemies while walking.  Can enter areas that ships and the hot air balloon can't enter.
Ship
     
Faster than walking.  Can also encounter enemies, such as pirate ships.  Can enter places that walking and hot air balloon can't enter.  To obtain a ship, approach a pirate's ship near the shoreline & defeat all of them in battle.  Becareful of the whirlpools...
Hot Air Balloon
About as fast as the ship.  Will not encounter enemies while on balloon.  Can navigate over mountains.  Must use 'Wind' spell to correctly navigate Balloon.  Can enter places that walking and ships can't enter.  While you are in the Balloon, you have a full view of all your surroundings, including forest areas.  Can't land on forest, plateau, mountain, river, sea or marsh areas.
Gate Travel
Instantaneous.  Travel from one gate location to another gate location during corresponding moon phases.  Gates will be located near 1 of the 8 virtuous towns.
Terrain Icon Description
Plains
Normal walking fields.
Brush
Same as Plains, except can have boulder obstacles in battlefields.
Forest
Shortens range of sight to a 3 x 3 area around you.
Plateau
Same thing as plains.  In battle, may have boulder/mountain obstacles in some areas.
Mountain
A big pointy rock, usually found in a copious amounts together near plateau areas.  Cannot cross over.
Poison Marsh
A poisoned patch of land.  Will inflict poison when crossed.
Fire
Marsh
A fiery marsh.  Will cause damage.  Can be found on world map near Abyss, or in battle from enemy attack, spell 'Energy' or item 'Oil'.
Force Marsh
Damage floor basically.  Same effect as fire marsh, but only found in towns, castles & dungeons.
Shallow Sea
Shallow water.  Located usually around the shoreline around landmasses.
Deep
Sea
Deep water.  Found in most of the world.  Not really much different from shallow water.
River
Small streaks of water.  Can be found on mainland or near shorelines.  Cannot cross over, except for bridges.
Bridge
A wooden bridge, used for traversing over water/rivers.
Shoal
Patches of water that are not passable.  One such shoal has some importance to it...
Whirlpool
Large vacuum of swirling water, found in sea areas.  Entering one may take you to someplace unexpected...
Town
1 of 12 towns found throughout the game; can encounter npcs & possible shops.
Castle
1 of 4 castles in the game, each with a ruling lord/lady.  Can find valuable information or items in them.
Shrine Places of meditation used to aquire partial Avatarhood in 1 of 8 virtues.  If requirements are met, Avatarhood is gained for that virtue; if not, you will be told what to do.
Dungeon Subterranean locations found throughout Britannia.  Monsters dwell within them.  Some contain the stones of virtue & principle altars.. others may contain other valuable information or items.  The final dungeon in the game, The Great Stygian Abyss, is surrounded by lava.