299,792,458 metres per second
The fax modem is used to send and receive fax messages by only having phone line (fax machine is not required). The scanned documents should be saved as digital file (image or PDF format) in order to be sent. So, in order to send a portion of a map you should first convert the map into digital file and than simply send it through the fax modem. The best way to convert it to a digital file is to use an optical character recognition (OCR).
Answer: Without GUI's being developed, we most likely would still be using terminal systems. Terminals require command/text input rather than mouse or other input. The invention of GUI's enabled people to use simpler input methods, rather then clunky text input systems. To sum, GUI's simplified the computer experience as we know today.
Hope this helped :)