What do map makers use as a key to explain all the symbols used on a map

Colors are often used as symbols. ... A map usually has a legend, or key, that gives the scale of the map and explains what the various symbols represent.

Different colors and shapes are used for different symbols

Explanation:

Maps are the two-dimensional representation of the global earth. They are commonly used by the geologists and the geographers in order the study the topography and the surface features in any particular location on earth.

The mapmakers often use symbols to highlight a particular object or location. These symbols are used in the map keys. These symbols are shown on the map by using different types of colors and each symbol has a different shape.

This helps in the identification of those places. For example, the triangular symbols are used to show the mountains, roadways are shown by using dashed lines, small airplanes demarcates an airport and so on.

the first historical instance of china engaging in internationalism was during the han dynasty.[1] at the start of the han dynasty, the huns in the north were attacking the frontiers of han and trying to obtain riches. emperor wu of han wanted to gain an alliance with a country called dayuezhi so the two countries could join together and fight against the huns.[2] to obtain this alliance, emperor wu sent zhang qian to the west to establish economic and cultural connections.[2] history records that during the han dynasty there were four primary avenues of contact between china and europe. they included the northern land route, the central land route, the southern sea route, and the far southern sea route.[1] the most famous of these routes is the central land route, or the classical silk road, comprising a network of roads stretching from northwest china to the ports of syria and the black sea, which passed through the oasis of the turkestans and northern persia.[1] the silk road was significant for chinese emperors because it provided dominance over central asia by developing resources and provided new markets for the export of china's most valuable resources.[1]

the roman army grew in size and became dominant in the mediterranean region.