[SIGMAPLOT v12] correspondence analysis to gaussian curve

John_

New Member
A correspondence analysis was performed, which generated an X and a Y coordinate. I have a third value that I want to use as a Z coordinate. How can these three values be used to create a gaussian curve in SigmaPlot?

gianmarco

TS Contributor
Hi,
in order to provide help, it wuld be useful if you could describe the issue in some more detail, providing some background of you study/analysis as well as your goals.
Provided that I do not understand what would be the purposes of "create a gaussian curve" in the context of Correspondence Analysis, I would like to know what the z coordinate represent.

Regards,
Gm

John_

New Member
not a problem, thanks for your reply. Looking back, you're right, there isn't much to go on. Here are some details:

The objective is to plot the abundance of harmful algal species in a 3d graph. A CA produced an x and a y coordinate for each species, which was successfully plotted on a 2d graph. The relative position of all of the species on the graph indicates their similarity to one another.

The point on the 2d graph represents the peak abundance of a species. Underneath that point (which isn't shown) is a unimodal mound, representing the distribution of this species. More area = more of the species. I want to create a gaussian curve as the unimodal mound. As for the shape of the mound, I have the number of units (length) of the base of the curve on the y and x axis.

The Z coordinate is another variable (biovolume) that I want to use to compare all of the species. Plotting the CA x, the CA y and the biovolume is no problem, but I want to plot a gaussian curve underneath the xyz point using the curve length data to shape it.

Overall, there are 5 pieces of data per species. An X value from the CA, a Y value from the CA, a Z value (biovolume), length on the Y axis and length on the X axis.

Any thoughts? or would you like anything clarified further?