Does anybody know a easy way to do CTD charts in excel?

Question

CTD - Conductivity, Temperature, Depth, and Salinity

Answer 1

There isn't one since excel doesn't allow multiple x-axes on the same chart (which is what you need to plot CTS as a function of D with D on the y-axis).  You can rescale CTS data so that the individual ranges scale from 0 to 1 and then put the maximum and minimum values for C, T, and S on a text insert.  This doesn't really fit into your "easy way" qualification though.  Please don't blame me, I didn't write excel.  :-)

In general, excel is a bad program to use for presentation graphics in science for reasons like this.  There are a lot of other ways it falls woefully short of the task (e.g., error bars, tick marks, multiple y-axes).  There are any number of graphing packages that will do what you want, plotting multiple x-axes on the same chart, etc.  Grapher (Golden Software), Igor (Wavemetrics), Sigma-Plot (Systat) are a few choices (listed in order of increasing cost (There are probably dozens of shareware ones out there as well, but I'm not as familiar with them)).  If you're going to be doing a lot of scientific graphing, it will be easily worth the money to buy a separate plotting package and just use excel for data processing and calculations.