Often a timestamp appears to be imprinted onto maps, telling us a time of day, rather than date. It is of course a lie (born of a convention). Hills and trees were drawn onto maps with the long evening shadows of a setting sun.
Maps followed figure drawing conventions: the body positioned so that a light source is in front and to the left to avoid the drawing hand casting a shadow where they drew. As north appears at the top of the map, so shadows were drawn with a notional light source “from the left extremity of the top of the drawing downwards”.This convenience for right-handers – to avoid casting a shadow upon the drawing – leaves me, and other left-handers, in the dark! Though even in my grandma’s day, left-handedness was frowned on, she had to learn to write and draw with her right hand.
As contours lines, and other innovations, came into play the shadow convention was rocked. The planimetric God’s eye view would suggest that only the crown of the tree appears – no trunk, no shadow – with ‘sun’ at perpetual midday, a view considered by some as “essentially imaginary or abstract in concept”. Although overhead, overall, lighting was seen by some as ‘more correct’ for maps, others found that ‘less talented artists’ who attempted slopes with “no light or dark sides” caused “a monotonous effect” upon their maps.
The whole shade / no-shade issue resulted in some curious juxtapositions once contour lines began to appear on maps. Contoured hills, devoid of shading, could be dotted with trees that still caught the evening sun. Others insisted the contoured hills should keep their shading, to avoid “pictorial difficulty” they desired contour lines to be limited to faint dots, so as not to “catch the eye unpleasantly”.
Wanting to experience drawing with shadows for myself, I set up shaded models hills in the studio. The shocker was not so much the irritation of the shadow cast by my hand – which was slight as I stood to draw and could move around the sketch – no, what was startling was how impossible it was to then attempt contour lines with an even stroke! The impulse to make lines darker on the shadow side was overwhelming, and however much I fought it, the lines still looked more like Japanese cartographer Kitiro Tanaka’s ‘Illuminated Contours’. I feel I’ve only just begun to scratch the surface of shadowy shaded relief.
 C. W. Pasley, Course of Instruction; (London: T Egerton, 1813)
 Eduard Imhof, Cartographic Relief Presentation (Berlin: Walter de Gruyter, 1982)
 Frome, Outline of the method of conducting a trigonometrical survey, (London: John Weale, 1840)
 Scott, “Representation of Ground,” in Papers on subjects connected with the duties of the Corps of the Royal Engineers, (Woolwich: W. P. Jackson, 1863)