Via: uk.ac.portsmouth.csovax; Thu, 19 Nov 1992 17:09:33 +0000
Newsgroups: bit.listserv.ingrafx
Date:         Thu, 19 Nov 1992 17:11:00 GMT
From:         MAPPAMUNDI@CSOVAX.PORTSMOUTH.AC.UK
Subject:      Efficiency of craDIR/FOLDER

Quantification of the efficiency of transmission of graphical data
******************************************************************
                  - A research proposal
                  *********************

To calculate the efficiency of transmission, a method is required to quantify
the data content of a cartographic image. Some cartographers have used
information theory techniques, which uses a calculated variable of entropy
(random disorganisation), to give a measure of 'uncertainty'. The greater
the uncertainty, the more the information. However, information theory,
although useful to electrical & electronic communication, has been unsuitable
for quantifying map data, as it does not take into account the geographical
pattern of data. Robinson & Petchenik (1975) rejected information theory's
direct application to cartographic communication, because of it's fundamental
concepts.

Quantification of transmission efficiency would be easier to calculate if
information theory was valid in this application, as the total data read
by the map percipient could be divided by the total data content of the map,
to give a ratio of efficiency of communication. Although not valid in
quantifying map data, the information theory methods may still be suitable
for application to quantifying the data content of other forms of graphic
representation.

A quantification method for map data probably exists, and it is most likely to
be in the guise of computerised analysis. If a computer can reduce a map to
numerical data, communicate it and then expand the data back to a map, then
surely the best hope for quantifying the geographical pattern of data must lie
in this direction.

This initial research proposal is expressing interest in formulating a formal
research proposal to study the following:

(1)     Evaluation of the suitibility of the application of information theory
to non-map graphical representation.

(2)     Construction of a method, probably involving computer-assisted
detailed analysis of data, to enable the quantification of data content of
a map.

(3)     Creation of a research method to calculate the transmission efficiency
of graphical data, from the map-maker to the 'average' map-precipient, based
on the amount of data contained by a graphic.

(4)     Construction of the 'average' map percipient, as advocated by Robinson
& Petchenik (1975), and his/her characteristics and tolerances.

(6)     Assessment of the transmission factors affecting data transmission
efficiency, ie. graphic type, format of data, use of colour, symbolisation,
typography etc.

This document is only an initial research proposal, and I would welcome
comments, suggestions, criticisms etc., or details of similar work that has
been, or is being undertaken.
I would especially like to receive information on the content of the following
literature, which has so far proved elusive:

Gokhman, V.M., et al. (1970) 'Special & general informative capacity of topical
maps', Unpublished paper for 5th Int. Carto. Conf. of I.C.A.

Kadar, I., et al. (1973) 'A practical method for estimation of map information
content', Unpublished paper from Meeting of Commission II, I.C.A., Budapest.

Muehrcke, P.C., (1973) 'Some notes on pattern complexity in map design',
Unpublished paper for discussion 'Map design for the user', A.C.S.M. ann.
meeting

Sukhov, V.I., (1970) 'Application of information theory in generalisation of
map contents', Int. Yrbk. of Carto. 11, 177-181.

                        *******************
References:

Board, C. & Taylor, R.M. (1976) 'Perception and maps: human factors in map
design and interpretation', in Trans. Ins. Brit. Geog. 2, 1, 19-36.

Robinson, A.H. & Petchenik, B.B. (1975) 'The map as a communication system',
in The Cartographic Journal, 12, 7-15.

                        *******************
I would like to express thanks  to Alan McEachren at Penn State University, for
pointing me in the direction of this topic.
                        *******************
Thanks for hearing me out!!

                Paul Darlow
                        Dept. of Geography,
                        University of Portsmouth, U.K.