I'm puzzled why you want to convert to arrays of pairs of coordinates into a single array of strings?

The only use I can see for this is if you are going to display them as part of the html on the page you are generating? Any other use would require you to parse the strings to retrieve the numeric values and that is never going to be efficient which appears to be your main concern.

I'm completely lost by your description of "The problem is that I am working within a foreach loop iterating over 96 lines (and doing this for each line) and it is also within a CGI which chocked after ~ line 22".

If you are doing this prior to printing them either the browser as part of your page or to disk somewhere, then there is no point in building a seperate array of strings first. You can just build the strings when you print it.

A little more explaination of what it is that you are doing, with perhaps a little more of the code would probably get you better answers.