Automated Computer Techniques _turpin

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aney Publishing

AN AUTOMATED COMPUTER TECHNIQUE FOR VESSEL FORM ANALYSISAuthor(s): Solveig A. Turpin and James A. NeelySource: Plains Anthropologist, Vol. 22, No. 78, Part 1 (November 1977), pp. 313-319Published by: Maney Publishing on behalf of the Plains Anthropological SocietyStable URL: http://www.jstor.org/stable/25667409 .Accessed: 09/10/2014 11:21

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ANAUTOMATEDCOMPUTERTECHNIQUEFORVESSELFORMANALYSIS

by

Solveig A. TurpinJames A. Neely

ABSTRACT

A computerized method for machine assisted

ceramic measurement from two-dimensional reproductions is given and its applicability in canonicalcorrelation analysis is tested.

INTRODUCTIONIn a recent edition of this journal (Turpin

et. al. 1976) a report was presented on astatistical analysis of fifty Caddoan vesselsfrom the Ben McKinney site, Marion County,Texas; designated as 42MR12 in the TexasArcheological Survey system. An attemptwas made through the use of canonicalcorrelation analysis (Veldman 1967, 1974) toassess the relationship between decorativetechniques, design elements, and vesselform. This met with limited success in thatcertain recognizable and characteristic forms

were delineated on the canonical variates(Fig. 1). However, certain smaller vessels,

notably bottle forms typed as Taylor Engraved(Suhm and Jelks 1962)were felt to have beeninadequately defined as a result of being

overshadowed by the physically larger vesselsand the numerical predominance of carinatedbowls in the sample.

Therefore, inorder to remove the effect of

size and orient the analysis more specificallytoward shape or form, two new complementary procedures were initiated and tested.

Improved Method of Data Recording

First, a more rapid and economicaltechnique was developed for measuringcomplete and restorable ceramic vesselsalong the polar coordinate axes used as formvariables incanonical analysis (Fig. 3).

A FORTRAN program written by Jerold R.

Johnson (1976) of the University of Texas at

Austin, which utilized the Rand tablet in theautomatic classification of projectile pointforms, was revised and adapted to accommodate ceramic vessels (see Appendix 1).

The Rand Tablet used for this project was

manufactured by the Data Equipment Company, model Grafacon 1010A. This off-linedevice consists basically of a flat glass screen,a photoelectric sensitive stylus, a keyboard,and a foot pedal triggering device foractivating the stylus. A continuous pointmode is optional wherein data points arerecorded from the stylus as it ismoved acrossthe screen. Ideally, this continuous point

mode could be adapted to record designmotifs as well as vessel form.

Thekeyboard

allows for the entry ofpertinent data such as sequence numbers,scale, provenience codes, and key symbols toserve as diagnostics to the decoding program.A Cartesian coordinate grid, embedded in the

glass screen, divides the X and Y axes into1024 units, each .25 mm. by .25 mm. Eachactivation of the foot switch causes thecoordinates of the stylus point to be read fromthe screen and punched onto an eight-levelpaper tape in a special binary code. TheFORTRAN program translates the character

punched paper tape into integer numbers andperforms the necessary mathematical operations to compute the recorded measurements.

Masking operations within the body of the

program translate the keyboard entries ofsequence numbers and scale into integernumbers. The scale of size can be altered to fitthe needs of the sample. For example, in thefirst tests of the technique all scale data wereentered simply as integer multipliers. In later

applications, the scale was modified to realnumbers to accommodate different ratios,

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Loadings

O .) .2 .3 .4 .5 J6 .7 .8 .9 1,0 0 ) ? .3 A .5 .6 .7 .8 .91.0

+Canonical Variate IB Canonical Variate 2B

+

Canonical Variate 3B Canonical Variate 4B

Figure 2

Fig. 2. Shape Oriented Canonical Variates

and the scale gives the centimeter length ofthe axis to the millimeter. These actual

measurements are relayed to the teletype andare recorded on a magnetic tape. The

measurements can also be punched ontocomputer cards immediately or when desired.Our procedure was to edit the tape by meansof the teletype unit or cathode ray terminal(CRT) for possible errors and make allnecessary corrections before commandingthe computer to punch the data cards.

To allow analysis of vessel shape, regardless of the range of size within the sample,

and eliminate biases in favor of large numbersof extremely small or large vessels, the actualmeasurements are then each converted toproportions relative to the height of thevessel. Each axis' actual length is divided bythe actual height of the vessel, thuseffectively setting the vessel height (polarcoordinate 10) at 100 percent.

While this program isdesigned specifically

to obtain polar axes measurements andproportional measurements, it ould easily beconverted to compute other relatively gross

measurements such as volume.

As noted, this computerized method maybe utilized with scale drawings as well asphotographic prints or transparencies havinga scale of size included. This provides accessto collections not readily available for directstudy. However, the primary advantage ofthis technique lies in its time-saving qualities.For example, data collecting and processingprocedures involved in the original study(Turpin et. al. 1976) took approximately 5hours. This length of time included themeasurements taken from scale drawings, thetime necessary to compute the actual

measurements, and the time required totransfer this data to punched computer cards.Using the automated process describedherein, similar procedures with the addition of

the computation of proportional measure

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_X?VI)_X(2U2)

^^^^^^^^^^ X(3)y(3)

Rgure 3

Fig. 3. Polar Coordinate Grid

ments, were accomplished on the samesample in 1 hour and 10 minutes. This time

included,not

onlythe

generationof a

punched data card deck, but the additionalstep of recording the data on a magneticstorage tape to facilitate data retrieval as wellas the correction and addition of informationby means of the teletype or cathode rayterminal (CRT). Comparisons between thehuman and machine-produced measurementsshowed less than a 2 mm. discrepancy at the

most.

Biasing the Canonical Analysis Toward Shape

In order to obtain a shape-oriented analysisas a complementary addition to the potentiallysize-biased original canonical correlationanalysis, the computation of the proportionate measurements was essential. Theseproportionate measurements were substi

tuted for the actual measurements thatdelineated the canonical variates shown inFigure 1 (hereafter designated as the Avariates) and the same canonical correlation

analysis (Veldman 1967, 1974)was

repeated.Because the vessel height had been set ata constant 100 percent itno longer functionedas a variable. The 22 design elements and 9remaining form measurements were transformed into 4 canonical variates or "roots'(Fig. 2), with a significance greater than .05(hereafter designated as the B variates).

A comparison between the graphic representations (Fig. 1 and 2) of the two analyses,both of which produced four statisticallysignificant roots, shows a similarity in

composition between canonical variates 1A

and 1B, the most significant roots, andbetween canonical variates 2A and 3B. Thesevariates delineate the form of the carinatedbowls in the sample. However, in the firstanalysis (A) the characteristic design elementsof the carinated bowls (Ripley Engraved andTaylor Engraved) were strongly correlated

with their characteristic forms on variates 1Aand 2A. In the modified analysis, these designelements diffused across variates 1B, 3B, and4B. The distinguishing design element between 1B and 3B was the occurence of red or

white paint. As white paint occurs solely onRipley Engraved in our sample and red paintpredominantly on Taylor Engraved thesevariates could be said to separate these types.However, the majority of the vessels themselves were found to correlate most signifi

cantlywith variates 1B and

4B,but there were

no strong consistent associations betweeneither type and these variates.

The graphic representation of variates 3Aand 4B clearly illustrates the results ofelimination of size as a variable in the analysis.Despite the extreme difference in size theconformation of these two variates is similarand clearly outline the forms of two vesseltypes, Harleton Applique and Bullard Brushed,

which in our sample were all large jars. Thedesign elements of both these types also

loaded heavily on these variates. As wasnoted above, design elements of the carinatedbowls also contributed to variate 4B butHarleton Applique and Bullard Brushedvessels were distinguished by their negativecorrelation with variate 1B.

Similarly, the smallest vessel in the sample,a miniature bowl did not contribute to anyvariate in the first canonical analysis, butloaded very heavily on variate 1B in the

second, shape-biased analysis.Canonical variate 2B

producedthe most

significant difference between the two analyses. Most clearly delineated on this variate is

Hodges Engraved, a type believed to havebeen traded into the site (Davis and Golden1960). Vessels with the strongest shapecorrelations to this variate were HodgesEngraved, Belcher Engraved, and SimmsEngraved, all imports to the area from thenorth and west (Dee Ann Story, personalcommunication). Within the variate, thesetypes were differentiated by their correlations

with the other significant roots. Simms

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vessels correlated negatively with variate 4B,Hodges negatively with all 3 other variates,and Belcher positively with design loadings onvariate 4B. One might then view variate 1B asan "importation vector" that could delineate acultural preference for certain shapes or

design attributes. The design element loading

most heavily on this root was the Jay element(--O) but it is not common to all imported

vessels nor unique to these types.The emergence of this variate in an

analysis oriented toward shape suggests it is alatent vector defined primarily by an underlying cultural preference for certain forms in

trade ceramics.

The bottle forms we hoped to isolate canbe defined only through negative correlations

with all four significant variates. However, thefifth root, which has a

significanceprobability

less than .1000, reflected the bottle shapeleading us to believe greater numericalrepresentations of this form with more

distinctly unique design attributes woulddefine a more significant variate.

We feel that by utilizing both the actualand proportional measurements of ceramicvessels, two perspectives may be gained.Inclusion of the variable of size produced

more definitive associations between the

design elements and forms of numericallysuperior ceramic types in the sample. Elimination of the size effect, through the use ofporportionate measurements, diffused thenumerically superior types across the canonical variates allowing the minor ceramic typesto emerge.

ACKNOWLEDGEMENTS

We wish to thank Jerold Johnson, the writer of theoriginal lithic measurement program, for his coopera

tion, Dr. Joel D. Gunn of the University of Texas atSan Antonio for his critical comments and Marge andJim nox of the University f Texas at Austin Hybrid

Computer Lab for their assistance.

APPENDIXI

FORTRAN IVProgram for CDC-6400/6600 Computer System, University f Texas at Austin.

PROGRAM MAC(TTY,OUTPUT*POLAR,PROP,TAPEi?P0LAR


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15 CALL BELLC(3tTTM#0,N)C THIS 30 DO LOOP ZEROES OUT ERRORS? THE, ERROR CODE IS 45B

DO 30 Ul# 1500IF 20,30

20 BUFR(I)?0C IP ERROR IS KEYBOARDHIT, ONE CHARACTER IS ZEROED IF ERROR ISC STYLUS HIT, FOUR CHARACTERS ARE ZEROED

IF( (BUFR( 1*1 )lAND', 100B).GT;0)22,2422 BUFR(I-1)?0 % BUFR(I*2)?0 S BUFR(I*3)?0 S BUPR(I?4)?024 IF((BUFR(I?1)'AND;40B);6T;0)26,3026 BUFRCI?1)*030 CONTINUE

WRITE(TTY#34)34 F0RMATC2/,* SEQ SCA PR1 PR2 PR3 PR4 PR5 PR6 PR7 PR8

>R9 PR10*,2/)REWIND TTY

C THIS 999 DO LOOP DECODES A LINE FROM BUFR AND WRITES IT BOTH TOC AN EXTERNAL FILE AND TO THE TELETYPE

DO 999 N?l,1500ICNT?1

C OPEN BRACKET J (CODE 242B) SIGNIFIES THE BEGINNING OF A NEW CASE

IF(BUFR(N).EQ,2428)50,99950 NSEQ?0NUM?3KOUNT?KOUNTfl

60 NSEQtNSEQ+l70 N?N*1

IF(NfGT;i500)GO TO 300IF(BUFR(N);EQf0)70.80

80 SSC(NSEQ)?(BUFR(N).ANDll7B)

IF(NSEQ;EQ;nUH)90,6090 N*N*frl

IF(N;gt11500)GO TO 300IP(BUFR(N)'.EQ90)90,100

C CODE FOR SPACE MARKER (BETWEEN SEQUENCE AND SCALE) IS 40B100 IF(BUFR(N)fNE,40B)GO TO 300

ICNT?ICNTtlNUM?NUM*2IF(ICNT;GT;2)110#60

110 DO 150 M>1,11ICNT?1

120 N?N*1IF(N;gt;1500)GO TO 300IF(BUFR(N)r. EG)'.0)120,130

130 BITS(ICNT)?BUFR(N)ICNT?ICNT*1IF(lCNT;GTl4)140,120

140 BITS(l)?LSHIFT(BITS(l)iAND:37B,5)BITS(3)?LSHIFT(BITS(3);AND#37B,5)BITS(2)?BITS(2)lANDf37BBITS(4)?BITSfOR,BlTS(2)Y(M)?BITS(3),0R.BITS(4)

150 CONTINUE155 N?N+1

IF(NtGT#t1500)GO TO 300IF (BUFR (N).EQft 0)155,160

C THE CODE 43B, SIGNIFIES AN END BRACKET 1 AS CASE TERMINATOR160 IF(BUFR(N).NE?43B)G0 TO 300

C K JS THE CENTIMETER MULTIPLIER FOR RAND TABLET COORDINATES

Kb.025

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C SC FIGURESSCALEFROMKEYBOARDUNCHSC?(FL0AT(SSC(5)))/(FL0AT(S3C(4)))

C LOOPS170 AND 175 FIGURE POLARCOORDINATESANDPROPORTIONSDO 170 I?2

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