1．地图的计算

计算类别

相关原理

比例尺的计算

比例尺=图上距离/实地距离。

地理坐标（经纬度）的计算

①1º经线长为111km, 1º纬线长为111cosαkm〔其中α为纬度〕；②北极星的地平高度等于当地纬度

海拔（绝对高度）和相对高度的计算

等高线图上任意两地相对高度的计算可根据：

(n-1)d ≤▲H<(n+1)d〔其中n表示两地间不同等高线的条数,d表示等高距。〕

⑴两地之间距离的计算

两地之间距离的计算主要有两种类型：一是已知比例尺求实际距离，只要量出所求两点之间的图上距离再用公式（实际距离=图上距离/比例尺）进行计算即可，需要注意的是单位一定要一致。二是通过经度或纬度差来进行计算，纬度差1度的经线长约为111千米，经度差1度的纬线长约等于111千米×cosφ（φ为所求地的纬度）。

⑵相对（断崖）高度的计算

断崖在等高线地形图上表现为若干条等高线的重叠处，其顶部的海拔高度应为几条重叠等高线中海拔最大值或之上，而底部的海拔高度应为几条重叠等高线中海拔最小值或之下，同时通过归纳得出，断崖的顶部和底部的相对高度H为：d（n-1）≤ H ＜ d（n+1） （其中d为等高距，n为重叠的等高线条数）

18. So ____ that no fish can live in it.

       A. shallow is the lake     B. the lake is shallow    

C. shallow the lake is     D. is the lake shallow

1~5 CBADB  6~10 ADADC  11~15 DBDBA  16~18 CBA

17. ____ is not everybody ____ can draw so well.

       A. It, all                B. It, that                     C. There, who        D. There, that

16. It was ____ I met Mr Green in Shanghai.

       A. many years that        B. many years before     C. many years ago that   D. many years when

15. Mary speaks in a low voice; ____ is difficult to know what she is saying.

       A. it                      B. that                   C. so                     D. she

14. Was it because he was ill ____ he asked for leave?

       A. and                   B. that                   C. that's                D. so

13. It was on October 1st ____ new China was founded.

       A. which               B. when                C. as                            D. that

12. It was in the rice fields ____ we had our league meeting.

       A. where               B. that                   C. in which            D. on which

11. It was through Xiao Li ____ I got to know Xiao Wang.

       A. who                  B. whom               C. how                  D. that

10. How long ____ to finish the work?

       A. you'll take         B. you'll take it      C. will it take you  D. will take you