It get hotter towards the center

what exactly get hotter towards the centre... I mean the earth does get hotter while you get closer to the core... but I am not quite sure what your question is

in cartography, a contour line (often just called a "contour") joins points of equal elevation (height) above a given level, such as mean sea level. a contour map is a map illustrated with contour lines, for example a topographic map, which thus shows valleys and hills, and the steepness or gentleness of slopes.

explanation:

space exploration has led to the development and technological improvement of many everyday items. (if this answer is wrong i will find the right answer) : )