EzGet: A Software Library to Facilitate Data Retrieval

A FORTRAN library called EzGet has been developed at PCMDI to facilitate retrieval of modeled and observed climate data stored in popular formats including DRS, netCDF, GrADS, and, if a control file is supplied, GRIB. You can specify how the data should be structured and whether it should undergo a grid transformation before you receive it, even when you know little about the original structure of the stored data (e.g., its original dimension order, grid, and domain).

The EzGet library comprises a set of subroutines that can be linked to any FORTRAN program. EzGet reads files through the cdunif interface, but use of EzGet does not require familiarity with cdunif. The main advantages of using EzGet instead of the lower level cdunif library include:

  • Substantial error trapping capabilities and detailed error messages
  • Versatile capability of conveniently selecting data from specified regions (e.g., oceans, North America, all land areas north of 45 degrees latitude, etc.)
  • Ability to map data to a new grid at the time it is retrieved by EzGet
  • Automatic creation of ``weights'' for use in subsequent averaging or masking of data
  • Increased control in specifying the domain of the data to be retrieved.
    • Taken together these capabilities will simplify the process of writing programs for accessing data stored in different formats and structures, including all the observed data sets and the model output from various model intercomparison projects (AMIP, PMIP, CMIP, etc.) archived at PCMDI.

    EzGet is updated and enhanced from time to time. Information on differences between the most recent and earlier versions of EzGet along with a description of current limitations of the software is available: see updates, bugs and limitations.

    If you wish to be informed of updated versions of EzGet (along with a description of any bugs discovered), please register. (If you register, you may expect to be sent email, but not often--no more than a few times a year.) 

    EzGet serves a different purpose from other software tools developed at PCMDI. EzGet is meant to be used in conjunction with FORTRAN programs that need access to data. For direct viewing and interactive manipulation of data, a Visualization and Computation System (VCS) has been developed. To transfer data to files, formats, or visualization systems, the Data and Dimensions Interface (DDI) has been developed. Neither VCS nor DDI can be called from a FORTRAN program.

    The EzGet software is currently available for the following platforms/operating systems: Sun/SunOS 4.1.3, Sun/Solaris 2.7, IBM RS6000/AIX 3.2, HP/HP-UX 9.0, SGI Irix 5.3, Cray C90, LINUX/Redhat 6.1.

    You may obtain via ftp the FORTRAN libraries and documentation comprising EzGet:

    If you will be reading data stored in netCDF format, you will need to obtain the netCDF library.

    Once you have transferred the EzGet files to your computer, you should uncompress and extract the individual files from the tarred files (further information available).
     

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    Last update August 11, 1997. For questions or comments on EzGet, contact Karl Taylor (taylor13@llnl.gov)

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