This means the Water Tribe is territorially smaller than it appears on the map, and the Fire Nation is larger. It is also heavily distorted, much like a Mercator projection, a type of cylindrical map that makes a round surface appear flat while still preserving loxodromes.
Yellow markers are locations that were first visited by Korra in 171 AG.Orange markers are locations that were first visited by Korra in 170 AG.Red markers are locations that were first visited by Team Avatar during Summer 100 AG.
The zoomed in square marks different locations in Republic City.