What is the best description of the world map's appearance? (Variant 1)

Geometry Level 2

${\color{#D61F06}}\text{This problem's question:}$ What is the best description of the world map's appearance?

The world map's projection is Azimuthal Equidistant . The center of the map is the sub solar point at 2019 12 21 2200Z. The night region of the world at that time is shaded darker. Therefore, where the sun is above the horizon is lighter.

Here is a sampling of maps drawn using the Azimuthal Equidistant projection centered on the capital cities of some geographically large area countries:

The entire world is represented with the outer edge of the map is the antipodal point.

Essentially circular map, lighter area off center with quarter of area of map. Essentially circular map with no shaded area. Essentially circular map, lighter circular area centered with half of area of map. Essentially circular map, lighter circular region at center with quarter of area of map. Essentially circular map, lighter semicircle with diameter through center of map Rectangular map with a wave of light and dark.

1 solution

A Former Brilliant Member
Jul 6, 2019

The subsolar point is at the center of the map. The antipodal point of the subsolar point is the entire outer edge of the map. The sun lights half of Earth at any time. It reaches half way from the subsolar point to the subsolar point's antipodal point. In the Azimuthal Equidistant projection that means the lit portion is $\frac12$ of the radius or $\frac14$ of the area of the map.

What is the best description of the world map's appearance? (Variant 1)

1 solution

0 pending reports