等高线画图工具。通过在多个图上划分等高线，来区分不同区域的划分，一般用在地理及力学上，比如气压分布、比压分布等。工程上有时也会需要标注不同区域的受力点等。-The contour drawing tools. Divided by multiple chart contour to distinguish between different areas of the division, is generally used in geography and mechanics, such as pressure distribution, pressure ratio distribution. Engineering sometimes need to label the different regions of the force point.