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Geological mapping, land and mine survey, and archaeological recording — three disciplines that share one problem and one kind of answer. Each has a notation designed to record a position or a measurement precisely enough that somebody else can re-find it: a strike-and-dip reading fixing the attitude of a rock surface, a boundary monument that outranks the deed describing it, a Harris matrix that made stratigraphic sequences comparable between excavations by throwing away everything except relative position. The recurring lesson is that several of these numbers are not measurements — a Mohs hardness is ordinal, a geological map's colour is age rather than rock, and a context number carries no stratigraphic order at all.
A long line with a short tick and a number, giving a bed's attitude.
A heavy line with ticks or arrows showing which side moved.
An arrowed line showing where rock has been bent.
Repeating patterns standing for rock type in a section.
A marked point recording where the ground was drilled.
A number from one to ten ranking scratch resistance.
Names and axis descriptions classifying a crystal's symmetry.
Capital letters naming layers down a soil profile.
A T-shaped mark on a plan showing who maintains a boundary.
Paint bands and dots marking trees for felling or retention.
A numbered tag identifying an individual animal.
Cuts in an animal's ear encoding an owner or a number.
A design burned or frozen into hide, read by a fixed grammar.
A diagram of stratigraphic relationships in an excavation.
A number identifying one deposit, cut or structure.
Hachures, levels and a datum line recording a vertical face.
A vessel drawn half in section and half in elevation.
A date with an error, a laboratory code and a calibration marker.
Painted or fixed points recording position underground.
A fixed stone or marker defining a legal boundary.
Colours standing for the age of the rock beneath.
Letters printed on a map naming the rock's age.
A number on a logarithmic scale, subscripted by method.
A number from zero to eight rating an eruption's size.
A height measuring how far a summit rises above its saddle.
A graduated board or post showing water level.
Times and heights of high and low water at a named port.
A wavy line marking missing time in a rock sequence.