Formal metadata: information and software
Formal metadata information and software
m
is a Tcl variable name. On output it is given a unique
value that allows mq to keep track of it. This command returns 1 if
the parsing was successful, 0 otherwise.
m
is a Tcl variable previously passed to the
metadata
command above, and element_name
is a
standard or extended element name. This command returns the
address of a matching element in hex, or zero. Use the address
in subsequent commands.
address
is the value returned from the
find_first
subcommand above or a similar subcommand below.
This subcommand returns the address of the first node at or below
the given address
that matches the target element_name
.
-list
is not
specified, the value is returned as a string. In this case, if you
specify -nonewline
, then the
lines are combined into one, with each line of the input separated
from the next by a single blank space. With neither
-list
nor
-nonewline
,
each line is separated by the newline character (ASCII 10).
-list
is specified, the
result is returned as a list of strings, where each such string
contains the text in one line of the metadata record. Using
this method, it should be easier to recognize groups of lines
that begin with > and handle them differently than
lines that do not. Note that blank lines in the input will
appear as empty list elements.
unset
for this purpose
because it seems to take a long time to complete.Return value | Meaning |
---|---|
standard | Element defined in the FGDC metadata standard (FGDC-STD-001-1998) |
profile | Element defined in a recognized profile of the FGDC standard. At this writing the Biological Data Profile is the only profile supported by these tools. |
extension | Element defined in a file loaded using an extensions directive in the config file. |
compound
or data
Note that this interface allows you to read and manage more than
one metadata record at a time. If you're going to read a lot of
records, you will probably want to use the
forget
for this purpose
command when you're done with each one.
You'll need Tcl/Tk installed on your system in order to make use of mq. You can download Tcl/Tk from the Tcl Developer Xchange, which currently provides the core distribution:
<http://www.tcl.tk/>If you're running Microsoft Windows, you will download a file whose name is something like tcl846.exe (that's correct for the 8.4.6 version of Tcl/Tk; as Tcl version numbers go up, the file name will change accordingly). Execute this self-extracting package and remember where it installs itself. It will create a directory called Tcl in one of your existing directories like "Program Files". Within that Tcl directory are subdirectories bin and lib. To install mq, find the file mq26.dll from the metadata subdirectory /usgs/tools/bin and copy that dll into Tcl/bin. Then create a folder in Tcl/lib. Name the folder "mq" and copy into that folder the file pkgIndex.tcl which is also found in the metadata subdirectory /usgs/tools/bin. To test, open a Tcl shell and type the command package require mq. You should get a response that is the version number of the mq package, which was 2.6.11 at this writing.
Peter N. Schweitzer Mail Stop 954, National Center U.S. Geological Survey Reston, VA 20192 Tel: (703) 648-6533 FAX: (703) 648-6252 Email: pschweitzer@usgs.gov