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Manual for psimpoll and pscomb

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Menu B: diagram scaling

B Scaling of taxa and samples
a Independent scaling for each taxon (off)       [off]
b Scaling covers excluded samples (off)          [off]
c Use defaults for marks on age/depth scale (on) [on]
d Use two columns for sum values (off)           [off]
e Skip every nth sample (0)                      [0]
f Interpolate to constant sample intervals (off) [off]
g Threshold for missing data values (-0.99)      [-0.99]
9 Leave this menu
Allows changes to factors that control various scaling properties:
Menu Ba: independent scaling
By default, a scale is found that will work for all taxa in the dataset, except that for those specifically marked as separate (e.g., charcoal, rarefaction data). This option disables the search for a common scale, and searches for a separate scale for each taxon;

Toggles from `on' to `off'.

Menu Bb: scale excluded samples
By default, if samples have been excluded, either because they were marked with an `x' (see Data preparation) or because they are outside a section of the sequence that has been selected (menu H), then data values in those samples are not considered when scaling plots. This option allows the data values in excluded samples to be considered. It means that when sections of the diagram are picked out, each such section will have plots with the same scaling as the others;

Toggles from `on' to `off'.

Menu Bc: labelling on age-depth scale
By default, psimpoll determines an appropriate scale with major and minor marks for the age-depth axis. This option enables the user to turn off the default and specify an interval for both major and minor marks. Interval must be given in the same units as those in effect for the age-depth scale (allowing for any conversion to ages). If the default is turned off, the current settings for major and minor marks are shown, and then prompts for new values;
Menu Bd: double column for sums
Values for pollen sums, identified by marking the taxon `name' with `*', are normally printed as a single column with upto 50 samples, but as a double column for more than 50 samples. Selecting this option forces double-column printing however many samples there are;

Toggles from `on' to `off'.

Menu Be: skip every nth sample
Allows omission of samples, regularly spaced. This is included to permit exploration of the sensitivity of certain analyses (notably zonation) to the number of samples in the dataset. A value of `2' causes every other sample to be selected for omission, `3' every third sample, etc. A negative value causes the selected samples to be included, and the rest omitted: a value of -3 causes only every third sample to be included. Thus, `2' and `-2' would both select every other sample, but the two series would have alternating samples. Values of `1' and `-1' are not allowed;

[Allowed range -100-100].

Menu Bf: interpolate to constant sample intervals
Selecting this item produces the following display:
6 Interpolate to constant sample intervals (off)  [on]

Enter '0' for on, or '1' for off
Allows a new dataset to be generated, based on the input data set, but with interpolated samples evenly spaced. The values at the interpolated samples are based solely on the pair of original samples either side of the interpolated sample (or on one original sample if there is one with exactly the same age or depth value as the desired interpolated sample). If 0 is selected, you will see the following submenu:
A Interpolation interval in age-depth units (1)   [100]
B Start level for interpolation (0)               [0]
C Stop level for interpolation (0)                [10000]
D Interpolation method (nearest pair)             [nearest pair]
9 Leave this menu
Q Return to main menu
Here you can select the interpolation interval, using the same units as the input dataset or age units (if a conversion to age is being done), specify where the interpolation should start and stop, and determine the interpolation method. The two available methods are `nearest pair', and `line fitting'. The first finds a pair of samples that lie either side of the interpolated level (however far away they are), and interpolates between them. The second uses all levels upto half of the interpolation interval either side of the interpolated level, fits a line through these points, and obtains the desired value for the interpolated level from the line. For the line-fitting method only, if there is only 1 (or 0) level available, the value for the interpolated level is given as for a missing data (-1, by default: see Menu Bg). If this option is selected, confidence intervals (menu N) are not available, because the value at any level is a combination of values from several levels.
Menu Bg: threshold for missing data
Allows change to the value of the negative number used to identify missing values. By default, this is -0.99. Anything more negative than this (e.g. -1) is used to mark a missing value. The value can be changed to any other negative number. This may, however, cause undesirable results for existing data sets that use -1, so use with caution.

[Allowed range: any negative real number].

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Copyright © 1995-2007 K.D. Bennett

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