You can use your garden hose to help lay out the borders of curved areas for gardens, flower beds, paths or small ponds. Just lay the hose along the proposed edge, check it for position, then mark out the curve by using a garden spade along the edge of the hose.
Carpenters who do rough construction get very proficient at “close-enough” measuring. For example, to quickly draw a line parallel to the edge of a board, you can place a pencil at the end of a combination square and move both the square and pencil along the board. Some combination squares have a hole in the blade for this purpose.