The caption below the graph in the image states that is how you should interpret the results in some places:
The map compares the popularity of the U.S. and China in each country based on their net perception score (measured as the difference between the share of respondents with a positive perception minus those with a negative perception of each country.) The country with the higher net score is relatively more popular, or less unpopular.
The caption below the graph in the image states that is how you should interpret the results in some places: