Agriculture Reference
In-Depth Information
7
Contours
In this chapter you will learn about:
The graphic conventions for representing and communicating landforms using con-
tour lines
•
How to manipulate contour lines in creating a variety of landforms
•
How to determine slope and precise elevations of any feature in the landscape
•
How to establish the slope of a land or paved surface using contours
•
IntroductIon
The focus of this chapter is the use of contour lines in site grading; a later chap-
ter will concentrate on the use of spot elevation. Together, contour lines and spot
elevations are the basic tools of the designer in creating the slope, three-dimen-
sional forms, and ultimately site-grading plans. Contours are especially useful
to the designer in helping him or her visualize the forms to be created in the
landscape, while spot elevations provide more precision to guide the detailed
site-grading design. Contour lines in a grading plan fill in the gaps, providing
critical information in transitional areas between hardscape features and areas
of pavement and walls. For instance, where dimensions and spot elevations
establish the height of walls, contours transition from the wall to the adjacent
landscape areas. Contours provide a similar transitional function in the design
of roadways, walks and trails, and paved areas, with spot elevations providing
the precision a contractor needs, in order to establish grades. Our basic tools for
providing grading instructions to a contractor are contours, spot elevations, and
