The elevation changes from 635 to 600 at the picnic area.
Explanation:
In the picnic area which is close to point 4 on the map, the elevation changes from 635 to 600. We see that the site chosen for the picnic has a very gentle elevation and would be easily taken as a flat plain surrounded by hills.
The contours here are far apart and it implies a flat area with gentle slope. The only creek here is the equation creek. The area is below 635.
