This module describes the differences between the NCAR Graphics user interfaces (LLUs, HLUs, and NCL). This module also indicates the advantages of using each interface and provides the criteria for deciding which interface to use depending on the user skill level and user application.
For a complete description of how to learn and use the LLUs and examples of the types of plots you can create, see the Low Level Utilities module.
Also, HLUs use resource files to set plot attributes like color, line thickness, position, etc. This allows developers to quickly change a plot's characteristics without having to edit and recompile any code. Tweaking the appearance of a plot is simply a matter of editing an ascii resource file, supplying a new value for a plot resource, and rerunning your code.
HLUs are also designed to aid GUI developers in their efforts to create graphical interfaces for NCAR Graphics applications. If you want to add this type of enhancement to your NCAR Graphics programs, then we recommend that you use the HLU library.
For a complete description of how to learn and use the HLUs, see the High Level Utilities module.
NCL contains a rich set of math functions that allow you to read and process your data dynamically from a command line interface or from within a script if you are using NCL in batch mode.
NCL also provides a mechanism for specifying plot characteristics so you can create NCAR Graphics plots by typing commands rather than developing and compiling a C or Fortran program. NCL has built-in defaults for quick and accurate visualization of data. The defaults can also be customized by the user via a user defaults file. Furthermore, visualization specifications can be entered and altered at the command line.
For more information about learning how to use NCL, see the NCAR Command Language module.
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