Header Files

I am new to arduino and i have a few questions on header files and its usage on programming arduino boards.

Can i use 1sheeld header file to program arduino without actually including the 1sheeld. For example i am including a GPS to arduino and if i want to program it can i use the 1sheeld library header file?

Other than some default libraries that are automatically called by the IDE, you always need to #include the header file of the library. The use of angle brackets (< and >) around the library header file name tells the compiler to look for the header file in the default path location for the IDE libraries. (Look in the libraries subdirectory of where you installed the Arduino IDE.) If you write your own library and it's part of your current project, you would surround the header file with double quote marks ("), which tells the compiler to first look in your project directory for the needed library files.

Yes, I understand that. But what if i am to use 1sheeld header file without actually using 1sheeld in my arduino project?