Symbol Location Plot

Use the Geochem Map > Point Plots > Location Plot menu option (CHSYMB GX) to plot geochemical sample locations. Location plots are used to represent the spatial distribution of sample locations on a map. When you use this functionality, the system searches the currently selected database for X and Y locations and plots a specified symbol on the currently selected map.

Symbol Plot dialog options

Mask channel

Select a mask channel from the drop-down list. If the use of the mask channel is enabled and set to this channel, only those data values whose corresponding mask channel values are not dummy values will be plotted or exported.Channels must have their CLASS attribute set to MASK to appear as selections in the drop-down list. If the mask channel does not exist, it will be created with its CLASS attribute set to MASK.

The default mask channel is set from the CHPREFERENCES GX (Geochem Import/Preferences...).

Script Parameter: CHSYMB.MASK

Symbol

symbol number

Script Parameter: CHSYMB.SYMBOL

Size (mm)

symbol size in mm.

Script Parameter: CHSYMB.SIZE

Weight

symbol weight

Script Parameter: CHSYMB.WEIGHT

Line colour

line colour

Script Parameter: CHSYMB.LINE_COLOR

Fill colour

fill colour

Script Parameter: CHSYMB.FILL_COLOR

Grouping

Grouping in the plot. If "Group by line/group" is selected, then symbol attributes can only be edited for entire lines or groups. If "Individual symbols" is selected, the symbols can be edited individually. The former selection is the default, and will be faster, especially for very large data sets.

Script Parameter: CHSYMB.GROUP (0: Individual, 1: Group (default)

Offset symbols?

If "Yes" is selected, symbols are offset from their actual locations and replotted so that overlap is avoided. The original location and the new location are joined with a line, and a small filled circle is plotted at the original location. Care should be taken when choosing the symbol size, because if the point density is too high, all the points will get pushed to the outside edge and your plot will look like a hedgehog (it also takes a lot longer!). The algorithm should work perfectly for the pie symbols, because they are all the same size. For the rose plots and bar plots an estimate of the average size is made and used to determine spacing and locations, so some overlap may occur for high-value data locations.

Script Parameter: CHSYMB.OFFSET: (0:No, 1:Yes)

Application Notes

The Mask channel can be used to determine which samples to plot. If you specify a mask channel, the system will plot the points based on the selected masking channel. Only locations that have a non-dummy value in the Mask channel will be plotted.