Everything in ASL is abstracted (this is not as bad as it sounds) each level in ASL is measure in relative heights of either a full or half level obstacle.
Here are some snippets from Chapter B
9.1 A wall represents a stone fence varying in height between one and two meters, and conforms to hexsides rather than the interior of a hex.
10.1 Hills represent terrain elevations which rise above ground level, and any terrain upon them rises normally from this new level to form new height equivalents. For example, a one level obstacle on a level 1 hill hex becomes a level 2 obstacle to the LOS of a unit at level 0. Inherent Terrain (B.6), whether a one-level Obstacle or Hindrance (e.g., orchard) or a half-level Obstacle (rubble) or Hindrance (crag, wreck) rises from the actual hill depiction (i.e., in a Hill-Orchard hex, LOS that crosses the hill depiction is affected up through level 2; LOS that does not cross the hill depiction is only affected through level 1). Other terrain (e.g., grain, brush, woods, building) is at the higher level throughout the entire depiction of the terrain in question, even if it appears to be rising from the lower level portion of the hill hex. A hill mass is depicted in various shades of brown; the lightest shade in any group of contiguous brown hexes being level 1, the next darker shade being level 2, and so on. The specific shades often very from one board to another and are relevant only in comparison to the other shades of the same hill mass. For aesthetic purposes, many hexes contain colors representing more than one elevation, but units therein are always considered at the elevation level containing the hex center dot.
*10.211 ALPINE HILL OPTION: The previous rule treats hills as a series of plateaus rather that constantly rising and rolling terrain. Those wishing to simulate the latter style of terrain can invoke a SSR for Alpine Hills by allowing equal-elevation hill hexes to block LOS through (not into) them.
22.1 A valley occurs at an elevation below ground level and represents an area much larger than a Depression. A valley is depicted by dark green background in obvious contrast to the lighter green used to represent ground level Open Ground on the same board. 24Q9 is an example of a valley hex.
23.21 SINGLE STORY HOUSE: All single hex buildings which do not contain a staircase symbol are considered one level obstacles to LOS. All units in such buildings are at the level of the other terrain in the hex. 1D4 is an example of a Single Story House.
23.22 TWO STORY HOUSE: A multi-hex building which contains no stairwell symbol is considered a 1 1/2 level obstacle to LOS despite also having another vertical level in each hex besides the ground level in the form of a level 1 capacity. All buildings of this type have an inherent stairwell present in each hex to allow movement between levels. Units on a Level 1 counter are considered to be at a level one higher than the surrounding terrain even though the building itself is only 1 1/2 levels higher than the surrounding terrain. 1F1-G1 is an example of a two story house.
That should give you some ideas of the complexity and "resolution" of the game, there are other things such as crests, slopes, movement and combat and what have you.