Using spreadsheets to produce stacked histogram, stacked line and spindle charts
By far the most widely available computer programs for recording, manipulating, and displaying numerical data are spreadsheets, such as Microsoft Excel™ and Lotus 1-2-3™. These are powerful and flexible tools and for most workers this is an obvious way of recording micropalaeontological data. However, they have been primarily produced for business users and have limited abilities when it comes to plotting scientific graphs. This note describes some indirect but rapid methods, for using the standard graphing tools in such packages, to produce additional types of graphs of value to micropalaeontologists.
STACKED HISTOGRAM CHARTS
Figure 1 is a stacked histogram chart, produced in Microsoft Excel™. This type of diagram is useful, for instance, in displaying variations in size of a species between samples through a section. Stacked histogram charts are not directly supported by any spreadsheets that I have seen. As a result, they can usually only be produced by rather inefficient techniques. For example, making a separate chart for each sample and then combining them in a graphics program. The indirect approach used here is to separate each true data series with a mirror image padding data series, which is not displayed. The entire diagram is then plotted as a single chart. The steps for doing this are:
(1) Enter the data (specimens per size class) in a spreadsheet (samples v. size classes).
(2) Between each pair of data columns insert a column with equations which will calculate mirror image padding data. These will have the form C3 = . . .