query

The query command allows the user to get information about a variety of aspects of the current GrADS session. Configuration, plot characteristics, graphics specifics, and file structure are some examples. The use of query pos combined with the coordinate transformations is the basis of many interactive applications with buttons and drop menus. The query command may be shortened to simply q. The syntax is:

When given without an option, the query command returns a list of the possible options. These are:

attr n Returns all attributes for file n (or default file if n is omitted)
cache n Returns netcdf4/hdf5 cache size for file n (or default file if n is omitted) (2.0.a8+)
cachesf Returns netcdf4/hdf5 cache scale factor (2.0.a8+)
calendar Returns calendar mode: unset, 365-day, or standard
config Returns GrADS configuration information
contours Returns colors and levels of a line contours (2.0.a8+)
ctlinfo Returns contents of data descriptor file
dbf Lists the contents of a shapefile attribute database (2.0.a8+)
define Lists currently defined variables
defval v1 i j Returns the value of defined variable v1 at point i,j
dialog args Launches a dialog box that prompts for text or numeric data entry
dims Returns current dimension environment
ens Returns ensemble metadata
fgvals Returns values and colors specified for gxout fgrid (2.1.a2+)
file n Returns info on file number n. Uses the default file if n is not given.
files Lists open files
font n Returns info on font number n. Uses the default font if n is not given. (2.2.0)
fwrite Returns status and characteristics of fwrite ouput file
gxconfig Returns configuration information about the graphics plug-ins (2.2.0)
gxinfo Returns graphics environment info
gxout Returns current gxout settings
lats Returns the status of the GrADS-LATS interface
pos Waits for mouse click, then returns position plus additional widget information
sdfwrite Returns the status of the sdfwrite options
shades Lists colors and levels of shaded contours
shp Lists the contents of a shapefile (2.0.a8+)
shpopts Returns settings for drawing and writing shapefiles (2.0.a9+)
string str Returns the width of string str in virtual page inches
time Returns info about time settings
udft Returns the user defined function table
undef Returns the output undefined value
xinfo Returns characteristics of the graphics display window
xy2w  v1 v2 Converts XY coords to world coords
xy2gr v1 v2 Converts XY coords to grid coords
w2xy  v1 v2 Converts world coords to XY coords
w2gr  v1 v2 Converts world coords to grid coords
gr2w  v1 v2 Converts grid coords to world coords
gr2xy v1 v2 Converts grid coords to XY coords
pp2xy v1 v2 Converts virtual page XY coords to real page XY coords

 

Usage Notes

For more information on the use of the query command, see the section of the User's Guide on commands that complement the scripting language.

Examples