旅行时间和距离
估计一段公路旅行的距离和时间.
两个相距甚远的城市间的旅程.
In[1]:=

cities = {Entity["City", {"Lisbon", "Lisboa", "Portugal"}],
Entity["City", {"Beijing", "Beijing", "China"}]};
以下为该两地间的测地距离.
In[2]:=

GeoDistance[cities]
Out[2]=

以下为计算出的公路旅程的长度.
In[3]:=

TravelDistance[cities]
Out[3]=

假设连续驾驶不停留,以下是估计的驾驶时间.
In[4]:=

TravelTime[cities]
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以下对象包含了实际的一套旅程向导.
In[5]:=

td = TravelDirections[{Entity[
"City", {"Lisbon", "Lisboa", "Portugal"}],
Entity["City", {"Beijing", "Beijing", "China"}]}]
Out[5]=

在麦卡托地图上表示轨迹(红色),并与测地轨迹(蓝色)进行比较,如我们之前所见,后者要短些.
In[6]:=

GeoGraphics[{Thick, Red, GeoPath[td], Blue,
GeoPath[{Entity["City", {"Lisbon", "Lisboa", "Portugal"}],
Entity["City", {"Beijing", "Beijing", "China"}]}]},
GeoProjection -> "Mercator", GeoGridLines -> Automatic]
Out[6]=

方位投影法更清晰的显示出,测地线比旅行路程更短.
In[7]:=

GeoGraphics[{Thick, Red, GeoPath[td], Blue,
GeoPath[{Entity["City", {"Lisbon", "Lisboa", "Portugal"}],
Entity["City", {"Beijing", "Beijing", "China"}]}]},
GeoProjection -> "Mercator", GeoGridLines -> Automatic];
Show[%, GeoProjection -> "LambertAzimuthal", GeoZoomLevel -> 4]
Out[7]=
