I am looking for some (preferably free) GIS software that will enable me to export multi-layered world maps (made up of shapefiles and KML files and so on...) as high resolution (21,000 pixels wide), single layered TIFF, JPEG or other raster format files, so that I can then edit them in Photoshop.
I am an artist, and new to GIS. I have recently started running the free MapWindow program on my computer. This has enabled me to start constructing some of the world maps that I'm looking for, though I can't seem to find a way of exporting them as images from that program.