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Communication and the Cartographer: 1. The "success" of a map or diagram as a visual means of communicating information between a cartographer and a reader is expressed as "percent map transfer function", a measure which remains theoretical but would be 100% when all the information intended for transfer was retrieved by the reader.
2. Effective visual communication depends on several elements of data presentation: (i) A statistical map or diagram must be neatly designed and drafted-an untidy or illdesigned map defeats its own pupose. (ii) A statistical map or diagram must be clear and unambiguos-such informative data as the Title, Scale, North Point, Legend and Class Interval are essential, not accessory. Anything that expedites communication is good; anything that obstructs or lengthens the path of communication is poor. (iii) There may be many ways of visually representing a set of data-there is no one correct way. A cartographer must assess the meaning of a set of data and decide on the impression or message to be conveyed. then a method must be chosen which will acieve the desired result in an incisive and effective manner. (iv) Simple messsages as the most effectively transmitted. Several maps or diagrams may be better than a single cluttered one. However "pretty" a map could look, it is the time taken by a reader to retrieve information from it that is the critical element that should govern its design. (v) The cartographer is powerful! the reader depends entirely upon the integrity of the person presenting the map or diagram. certain facets of the data set can be emphasized or suppressed by skillful use of the cartographic languae-indeed, the reader may deliberately be misled. 3. A cartographer requires certain skills and qualities. Fundamental is the ablity to use basic drafting equipment with a steady hand and eye for a balanced arrangement. Essential too, is a knowledge and practical facility with cartographic language and methods of data generalization and analysis. Desirable is a basic honesty and will to serve the reader.
Geodesy:Though one learns the elements of Earth shape at an early age, it is apporpriate to review the basic properties of the physical body of which various kinds of scales od maps are made. To simplify reality for the purposes of description, the earth is imagined as being a true shperical body. location on this hypothetical sphere can then be defined by reference to its geometry, first by means of Latitude, then by Longitude. Latitude was understood by early traders traveling between Egypt and Cyprus, the relative position of the north star being seen to shift as the observer moved north or south. Longitude was not a feasible measure until a reasonably accurate chronometer was developed agaisnt which the difference between local sun-time and the time as one agreed-upon location could be measured. | |||
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