Just an update if people are following this link in the future:
Install the following.
for MacOS is on this page. Be sure to get the PPC platform (i.e. the .dmg file) this way you don't have to mess around with the terminal and unix stuff. I'd also get the pdf help file.
natvigate to the download section of the site. This again is a simple drag-to-applications install process.
Now this is more or less what I figured out to get Aquaterm and GNUplot working with the help from people in this post. I haven't tried calling GNUplot from Xcode yet. But I will be figuring out how to use the adapters soon. There are other people here who know how to do this.
GNUplot, being unix based looks for a file in you home directory called '.gnuplot', this is like it's preferences if you will. However '.filename' files are invisible on MacOS because they are reserved for the system. You will need to do the next bit from the terminal.
But first a few unix commands for the terminal:
cd = change directory
cd ~ = change directory to your home (the tide character always mean home to MacOS)
cd / = change directory to the root
ls = list file in directory
ls -a = list all (even invisible files)
ls -al = as above but with metadata printed too.
mkdir = make a directory
mv = move a file
info nameOfCommand = get info on a command
Firstly, open TextEdit and make a file with the text 'set terminal aqua', click save, make sure you unclick the square box because we don't want it to be saved as a .txt file. In the message window that pops choose the Use "." button.
Now every-time GNUplot starts up it will load aquaterm to display your data.
Secondly, we need to change the path variable to make the 'system' know where GNUplot is. (If you type 'gnuplot' from the terminal and get a 'can't find' type error you need to do this.)
NB - I don't know how to permanently change the PATH variable so I am editing PATH every time the terminal loads.
In terminal type, 'export'. You should be able to see a line called something like PATH='bin:more:directories/listed/here:new/directories/separated/by:colon' this is the value of your PATH variable. *IMPORTANT* do not do delete any of the directories in this string. My PATH:
Highlight and Edit --> Copy ALL of your PATH (from the first P of path to the very last " that terminates the string).
Now make a file called .profile in your home directory (same technique as last time). Inside the file, Edit --> Paste the PATH that you just copied. But include the path to GNUplot, which should be /usr/local/bin. make sure you add a colon after the pervious last entry to tell the system that this is a new directory in which to look. Save the file as we did before.
Close the terminal.
Open the terminal and type 'gnuplot'. GNUplot should now open!
Inside GNUplot terminal type 'plot sin(x)' (with out the inverted commas). AquaTerm should open and display your plot. If not make sure that AquaTerm is open and try again, this oddity was reported before, have a look here.
The next time you launch GNUplot from the terminal in will open AquaTerm automatically.
Please post if there is a better way of doing things. You might want to post too if you know how to change the path by not editing the .profile. Viro has posted before saying that this won't work when trying to call GNUplot from inside your Xcode projects, you have to change it globally. Hope this as been useful.