Plans are measured drawings of layers and structures on excavations, recorded horizontally. This means that the
finished plan should represent the surfaces being drawn as if from above, to scale (usually 1:20 or 1:10, but for
large areas 1:100 is sometimes used). Plans are drawn on site, and then inked-in (and increasingly, computer-digitised)
afterwards to create a permanent record.
Plans are produced on a drawing board permanently covered by graph paper. Secured over this is a blank sheet of
semi-transparent drawing film. The plan is drawn on this in pencil. If the plan is to be drawn at 1:20, then each
centimetre square on the graph paper represents 20 cm on the site. A one metre square wooden frame strung out in
20 by 20 cm squares inside (called a planning frame) is placed over the archaeology to enable the planner to
visualise the grid on the ground, and draw more accurately. The frame must be absolutely level
(not always easy on a sloping site) otherwise the drawing will be distorted by perspective. Sometimes it is
necessary to position a frame above the ground using adjustable props, making sure it is level with a spirit-level.
If there is a gap below the frame, a plumb-bob on a string is used to transfer the grid intersections vertically to
the surface being drawn.
The outlines of different deposits and structures are drawn on the plan, and context numbers added to identify them.
Where features such as pits or ditches have already been excavated, the edges of these cuts are shown. 'Hachures'
(lines with small arrows on them) are added to show the direction and shape of the cut. A level or total station is
used to measure heights at various points and these are marked on the plan. Plans must always be carefully located
within the site grid, with grid co-ordinates marked at their corners.
Planning is a skill that requires much practice and patience, and even then some people find it difficult to get it
right. Many excavation teams have a full-time 'planner' - somebody with good visual and drawing skills who can work
quickly, consistently and accurately and make sure that this vital recording activity is done properly.
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