It is almost as if the photographer takes the viewer by the hand, draws them into the landscape, and points the way. The viewer's eyes are compelled to follow the line. Curves are graceful, rhythmic, dynamic and add energy to an image. They can separate or connect elements or simply offer a balance.
curves can have a mesmerizing effect on the viewer as their eyes sweep back and forth through the frame. They also create a sense of depth as the eye moves from foreground to background. curves can be found in the natural flow of a river, winding road, or a pathway
They are created when objects in the frame imply the shape. Rather than the shape jumping out at you in the bend of river, the photographer has to put a little more work into composing an image to make the elements in the scene form a shape, or by recognizing and taking advantage of a shape when it happens.
Remember you are guiding the viewer’s eye so choose carefully where you want the the eye to enter the frame and where it should go from there.
Other compositional “rules” can also be applied. For example, you can have a symmetrical composition or follow the rule of thirds as well as having a curve shape in the frame for an effective and dynamic image.
Make sure the image is well balanced with your curve not too close to the edges of the frame.