To read a map, take note of the compass direction, the legend, and the reference lines.

为了读懂地图，要注意指南针方向、图例以及基准线。

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Then Ecosign sends foresters and surveyors equipped with GPS, topographical maps and compasses to the slopes to scramble the steep trails, marking central reference lines with flagging tape, determining boundaries and figuring out where trees need to be removed.

WSJ: Paul Mathews of Ecosign, Scouting the World for Killer Ski Slopes | Creating

It hasn't been given a name yet so lets reference it as "The Big Graph" where all lines intersect at 2020.

CNN: Just Imagine - Living Space: Your views