Data Worksheet

The GS+ Data Worksheet

The GS+ Data Worksheet contains data for analyses. Data can be entered manually or can be imported from files in a wide variety of formats. Predefined formats include those for GeoEas and Surfer®. Entered data can be edited, filtered (bounded), and can be temporarily or permanently deleted from subsequent analyses. Temporary deletions are made with a click of the right mouse button, and data are just as easily undeleted.

Field assignments (assigning fields or columns to x-coordinate values, y-coordinate values, etc.) are made in the worksheet window by clicking on a top row, which brings up a small dialog window. Once a data set is defined, descriptive statistics can be viewed in the Data Description window. The GS+ worksheet supports up to 2 billion rows and 64 columns.

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GS+ Descriptive Statistics

Descriptive statistics for the variates defined in the Data Worksheet window appear in the Data Summary window. Information is provided for both the Z-variate (on the exposed tab in this picture) and for the X, Y Coordinates (in a separate tab that includes an x, y sample posting). The Z-variate can be transformed here in order to better normalize the variate's distribution prior to geostatistical analysis. During kriging, transformed data can be written to kriging output files in transformed form or results can be back-transformed to the original measurement domain. A full-window frequency distribution is available by clicking on the small frequency distribution image.

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GS+ Frequency Distribution

The GS+ Frequency Distribution provides a visual check of the need to transform a Z-variate prior to further analysis. Distributions can also be plotted as Normal Probability or Cumulative Probability curves from the Plot menu at the bottom of the screen. The Edit Graph command allows axes, titles, backgrounds, and the number of frequency classes (bars) to be changed. When data are transformed via the Data Description window, both the nontransformed and the transformed data are graphed, as below.

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GS+ Scattergrams (Coordinate Postings)

The Coordinate Posting window provides a map of coordinate locations coded by data values. The location of each data point in the active data set is marked by a symbol corresponding to its relative value. Both the number of levels displayed as well as the range for each level is user-defined. A similar window provides coordinate postings for 1d data.

Data may be grouped in one of three distributions:

Quantiles – in which Z data are placed into groups of equal frequency, i.e. into groups that have the same number of sample values. Quartiles (the default graph) are divided into 4 groups, percentiles into 100 groups, etc.
Intervals – in which Z data are placed into groups based on even intervals of the data range, without regard to how many sample values are placed in each group.
Custom – in which you can define how individual groups are defined (upper and lower bounds).

This posting describes all data in the current Data Worksheet.

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