Hello, I am new to IDL but am familiar with how Microsoft Excel can be used to manipulate data. I use iPLot to visualise data by following these steps: 1. I point to the file in question in the default folder by: f ='C:\Users\rxj72462\Desktop\Default\overnight.xls' 2. I then find that f is a string variable but contains the data which I want to visualise. So I can do: iPlot, f and it will plot gobblygook but I can bring up VISUALISE from the iPlot pull down menus and I can point towards the actual data. My question is, how do I work on the actual data within the F string (ie how do I extract the numerical values from the F string in order that I can manipulate the data mathematically? Thanks, Nevica