Hachure

Hachure is a map shading technique in which relief is represented by short, straight lines known as hachures. The lines are typically arranged in a regular pattern and are oriented roughly perpendicular to the contours, following the slope of the terrain. The density, length, and sometimes angle of the lines convey the steepness and texture of the landscape: steeper areas receive more or longer lines, while gentler slopes have fewer lines. Hachures are commonly used to indicate elevation and relief in lieu of filled shading or contour lines, especially on early or wood-engraved maps where detailed shading was difficult to achieve.

History and usage: The technique emerged in early modern cartography and was widely used in European maps from the 16th to the 19th centuries. It was gradually supplemented and often replaced by contour lines and color relief shading with the advent of more precise surveying and printing methods. Today, hachures survive primarily in historical reproductions and in stylistic or decorative maps, where they evoke a traditional or old-fashioned appearance.

Etymology and scope: The term comes from the French hachure, from hacher meaning to hash or chop, reflecting the hatch-like marks. In modern cartography, hachures are rarely the primary relief method but may be employed for historical accuracy, artistic effect, or educational illustrations to demonstrate how terrain was depicted before more quantitative methods became standard.