Final answer:
A semi-permanent reference point that serves as the basis for a map is known as a frame of reference, such as the Prime Meridian for longitude measurements on Earth. Key map elements also include scale, orientation, and explanations for symbols used.
Step-by-step explanation:
The term for a reference point that serves as the basis for a map and is somewhat permanent would be a frame of reference. This can be a specific point or a collection of points that are used to define positions and measure motion in relation to this point. For example, on a map, the Prime Meridian is an internationally recognized reference point, from which the longitude of other points on Earth is measured. The Prime Meridian, passing through Greenwich, England, has a defined longitude of 0°. In the context of classroom instructions, the door could serve as a reference point, allowing people to describe their position as '2 meters from the door, directly inside.'
When creating or using maps, it is also essential to know the ratio of distance on the map to the actual distance on the ground, which is known as scale, and other elements such as arrows indicating north, and explanations for any symbols, colors, or icons used on the map. Furthermore, understanding the source of geographic information, the map projection used, the year of the map's release or revision, and any associated publication or guidebook is important for map interpretation.