Names, units-designations, and text descriptions are stored in the file-headers and may be accessed via the FDESC data structures after a call to DESC3(). The reverse procedure is used to create new files: store the file's description in the FDESC data structures, and then call OPEN3() .
For C programmers: The IOAPI_Cdesc3
fields (gdnam, upnam, execn, fdesc[], updsc[], vname[],
units[]
, and vdesc[]
are blank-padded
character arrays (padded to a length of NAMLEN3=16 for name fields and
MXDLEN3=80 for description variables), not null-terminated C strings.
On the other hand, file name and variable name arguments
to read3c()
, write3c()
, interp3c()
,
and xtract3c()
should be null-terminated
C strings.
Within a file, all the variables have the same dimensions, horizontal coordinate system and horizontal grid structure, number of layers and vertical grid structure, time step structure, and type of data structure, although they may have different basic data type.
Layers range from 1 to NLAYS3D
, where
NLAYS3D
is the attribute in FDESC3
file
descriptions for the number of layers.
Vertical coordinate and vertical grid descriptions found in
FDESC data structures
fully characterize the layering structure of files.
There are three kinds of basic data type which individual variables may have, as indicated by the following "magic number" parameters defined in PARMS3.EXT , and stored in the VTYPE3D arrays of FDESC3.EXT :
There are also three kinds of time-step structure supported, discriminated on the basis of the time step TSTEP3D, and stored according to Models-3 date and time conventions, and found in FDESC file descriptions . These kinds of time step structure are:
There are eight types of data currently supported by the I/O API. Data type is indicated by "magic number" values for FTYPE3D in file descriptions such as those found in FDESC3.EXT. Definitions for these magic numbers are found in PARMS3.EXT . The data types, together with the names of the magic numbers, are:
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