The Landscape as Two Parts
A lot of game art is delivered as 2 dimensional art, whether it is a room in a castle, a city, or the exterior land. Scenery that is divided into rooms is easier to manipulate, and you can determine what is in each room, by dividing the landscape into pieces or subsets.
If you have rooms or subsets of the landscape, a closer look will show you the topography or altitude of the landscape, but it will also show you things like textures of land, or other deliverables for the game that is being created.
The animation team that is working on the room or landscape will also spend time on lighting and shadows. This is a separate task from creating the land itself. The lighting and the shadows may be separate layers in the art, and they add a significant amount of believability to the overall game. There are tools that can automate the creation of the look, but nobody ever tells you how long it takes for the automation to render.