今天開始學習第三課，下面是課程結束之后老師的總結。
Finding data is its own challenge that you will always be trying to master.
第一節是重復一遍如何找到數據的，具體方法在第一堂課的指南中提到。
You now know how to use data frames, create basic layout views, andexport maps as PDFs.
這一小節有一些重點：
layer property：層的屬性，其中包含coordinate system
data frame的設置：借助view——layout view調出，其中可以添加title并且能通過pdf導出
We covered navigation in layout view and adding legends, scale bars,north arrows, and text store map layouts.One thing to remember is that if you want to change the properties oroptions of something in layout view, that's accessed by double clicking on it.See you in the next activity.
這一小節主要講了如何修正layout view，以及如何增加圖例、比例尺以及指北符號。
