--> Abstract: Point-Counting with Personal Computers, by D. W. Downey; #90958 (1995).

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Abstract: Point-Counting with Personal Computers

Donald W. Downey

Point-counting with personal computer hardware and software significantly increases the ease-of-use and integration of data into graphing software. I use a Macintosh computer with Hypercard software programmed for point-counting and Deltagraph for creation of ternary charts. The system is inexpensive and easy-to-use, requiring about two hours of set-up and training time. Software costs are about $400.

Graphical interfaces on personal computers allow creation of screens with buttons and numeric fields that look and operate like mechanical point-counters. Hypercard allows creation and copying of buttons linked to counting fields with scripts. Addition of buttons as new varieties of grains are identified provides flexibility. Pushing a button or key adds one to the current count. On-screen labeling of grain type for each button and field reduce operator error.

Saving point counts for each sample point on a separate screen allows development of a computerized database. Additional fields for sample location and petrographic descriptions connect to the primary screen through button links. Integration of the collection of point-counts, descriptions and sample locations organizes the petrographic research phase of the study.

Spreadsheet and statistical analysis programs such as Excel and Statview total the modal varieties and allow a quantitative interpretation of the difference between sample points. Deltagraph creates ternary charts in color. To determine the provenance by modal analysis of point-count data with QFL plots, scanning and scaling of provenance field charts published by previous workers creates overlays for the ternary charts.

AAPG Search and Discovery Article #90958©1995 AAPG Pacific Section Meeting, San Francisco, California