Comparative Archaeology Database, University of Pittsburgh
URL: http://www.cadb.pitt.edu
Email: cadb@pitt.edu

Machalilla Settlement Dataset
Alexander J. Martín

Area Density Index and Demographic Projections

The data files DENSITIES.TXT and DENSITIES.XLS contain data on the densities of ceramic material for each lot (by period), calculations of the Area-Sherd Density Index, and estimated population numbers for each lot (Martín 2009a:60-62). DENSITIES.TXT is an ASCII text file; DENSITIES.XLS contains the same data in the form of an Excel spreadsheet. Each line represents one collection lot. There are 553 lines in the text file, each with 16 variables separated by commas. The variables are, in the following order:

1

Lot Number

2

Formative Period sherd count

3

Regional Development Period sherd count

4

Integration Period sherd count

5

Total area of collection circles (in square meters)

6

Lot density for unsystematic collections

7

Surface density of Formative Period sherds (sherds per square meter)

8

Surface density of Regional Development Period sherds (sherds per square meter)

9

Surface density of Integration Period sherds (sherds per square meter)

10

Lot area (in hectares)

11

Formative Period Area-Sherd Density Index

12

Regional Development Period Area-Sherd Density Index

13

Integration Period Area-Sherd Density Index

14

Formative Period population estimate

15

Regional Development Period population estimate

16

Integration Period polulation estimate

The first line of the ASCII text file, for example, looks like this:

1,8,3,6,37.70,,0.212,0.080,0.159,0.2875,0.0610,0.0229,0.0458,0.05,0.05,0.17

This indicates that the data pertains to collection lot 1, in which there are 8 Formative Period sherds, 3 Regional Development sherds, and 6 Integration Period sherds. The total area of the collection circles used to pick up the sample of artifacts was 37.70. Since this was a systematic collection, and the densities are calculated using this area, it was not necessary to assign a density in the field, which is why the next variable is empty. Hence, for this lot the surface density of Formative Period sherds is 0.212 sherds per square meter, the surface density of Regional Development Period sherds is 0.080, and the surface density of Integration Period sherds is 0.159 per square meter. This lot is 0.2875 hectares in size, and so the Formative Period Area-Sherd Density Index is 0.0610, the Regional Development Area-Sherd Density Index is 0.0229, and the Integration Period Area-Sherd Density Index is 0.0458. These numbers are used to extrapolate an absolute population number of 0.05 individuals per century for the Forative Period, 0.05 individuals per century for the Regional Development Period, and 0.17 individuals per century for the Integration Period.

The last, or 553rd, line of the ASCII text file is:

553,0,0,43,7.07,,0.000,0.000,6.083,0.0000,0.0000,0.0000,0.0000,0.00,0.00,0.00

This indicates that the data pertains to lot 553, in which no Formative or Regional Development Period sherds were recovered, but which contained 43 Integration Period sherds. The total area of the collection circles used to pick up the sample of artifacts was 7.07. Since this was a systematic collection, and the densities are calculated using this area, it was not necessary to assign a density in the field, which is why the next variable is empty. Because there were no Formative of Regional Development sherds, the surface densities for the Formative and Regional Development Periods are 0.00 and 0.00. The surface density for Integration Period sherds, on the other hand, is 6.083 sherds per square meter. Since this lot is one of 39 special collection lots belonging to shell concentrations recognized during survey, there is no demographic reconstruction carried out for it, and so the remaining variables all measure 0.00.

Click here to download the file DENSITIES.TXT (44 KB) or the file DENSITIES.XLS (135 KB).


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