What is the meaning of Liu Bei's transformation from the Three Kingdoms to the circle and triangle in topographic information?

It represents the combat capability of the arms in this terrain. Round represents the ability of the army 100%. The triangle represents 90% ability.

There are five more stars. Solid circle. X.-. And other symbols. Represent respectively

★ 120% of the ability to play.

◎ 1 10% capacity.

○ 100% of the ability to play.

△ 90% ability to play.

× 80% of the ability to play.

-Troops cannot walk on this terrain.