投影造成的面积变形
麦卡托投影法(Mercator projection)不能保持面积. 该方法并不是等面积投影.
In[1]:=

GeoProjectionData["Mercator", "EqualArea"]
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非洲的面积比格陵兰面积的大 14 倍以上.
In[2]:=

GeoArea[Entity["GeographicRegion", "Africa"]]/
GeoArea[Entity["Country", "Greenland"]]
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但在麦卡托地图中,非洲和格陵兰的面积却近乎相同.
In[3]:=

GeoGraphics[{GeoStyling[Green],
Polygon[Entity["Country", "Greenland"]], GeoStyling[Red],
Polygon[Entity["GeographicRegion", "Africa"]]},
GeoProjection -> "Mercator", GeoRange -> "World",
GeoBackground -> "Satellite"]
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使用等面积投影法,比如摩尔魏特(Mollweide),来表示更合适的和相对大小.
In[4]:=

GeoProjectionData["Mollweide", "EqualArea"]
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In[5]:=

GeoGraphics[{GeoStyling[Green],
Polygon[Entity["Country", "Greenland"]], GeoStyling[Red],
Polygon[Entity["GeographicRegion", "Africa"]]},
GeoProjection -> "Mollweide", GeoRange -> "World",
GeoBackground -> "Satellite"]
Out[5]=
