Example

For contour mapping, the reduced level $($RL$)$ of the points were obtained from levelling used by $15m15m$ grid system as follows.a$)$ Draw the contour map using scale $1$:$500($grid lines: vertical lines starting $1$ and horizontal lines starting A$)$b$)$ b$)$ Find the percent slope between points C$3$ and A$1.$c$)$ c$)$ Draw the section of the line Cl to C$5$ using scale $1$:$500$ for X axis and $1$:$50$ for Y axis.