The FITS format used in astronomy was defined mainly for archiving, transmission, and processing. In other situations, the data might be useful in other formats. For example, when you are writing a paper or report, or if you are making slides for a talk, you cannot use a FITS image. Other image formats should be used. In other cases you might want your pixel values in a table format as plain text for input to other programs that do not recognize FITS. ConvertType is created for such situations. The various types will increase with future updates and based on need.
The conversion is not only one way (from FITS to other formats), but two ways (except the EPS and PDF formats132). So you can also convert a JPEG image or text file into a FITS image. Basically, other than EPS/PDF, you can use any of the recognized formats as different color channel inputs to get any of the recognized outputs.
Before explaining the options and arguments (in Invoking ConvertType), we will start with a short discussion on the difference between raster and vector graphics in Raster and Vector graphics. In ConvertType, vector graphics are used to add markers over your originally rasterized data, producing high quality images, ready to be used in your exciting papers. We will continue with a description of the recognized files types in Recognized file formats, followed a short introduction to digital color in Color. A tutorial on how to add markers over an image is then given in Marking objects for publication and we conclude with a LaTeX based solution to add coordinates over an image.
Because EPS and PDF are vector, not raster/pixelated formats