srtm是美国nasa指定的精度为90米的全球高层数据，函数srtmshow可以利用matlab读取这样的数据，并且以mesh的形式显示他们。用法：srtmshow（‘c:/.../XXX.ttf’,60,70,60,70）。表示读取文件XXX.ttf中横向60 -70 ，纵向60 -70 的数据并显示他们。

-srtm the United States designated the accuracy of nasa' s global top 90 m data, the function srtmshow can use matlab to read this data and to display them in the form of mesh. Usage: srtmshow (' c :/.../ XXX.ttf' , 60,70,60,70). That read the file XXX.ttf 60 -70　in the horizontal, vertical 60 -70　of the data and display them.