Usage of PALM NCL script crosssections.ncl
==========================================
Last change: $Id: crosssections.usage.txt 127 2007-10-23 11:05:25Z letzel $
Marcus Letzel, 17 July 2007

Command-line syntax
===================
ncl crosssections.ncl [parameters]

The parameter syntax depends on their data type:
A) numeric data    : parameter=value      (for example t=0)
B) character string: 'parameter="string"' (for example 'var="u_xy"')

Alphabetical parameter list
===========================
Name	Default value		Meaning
-----------------------------------------------------------------------------
cm	"ncview_default"	colormap
di	""			input directory (with final /)
d	=di			output directory (with final /)
fi	"example_xy"		base name of input file (without suffix)
fo	""			base name of output files (without suffix)
fill_mode "AreaFill"		fill mode for mode="Fill":
				"AreaFill", "RasterFill" or "CellFill"
mode	"Fill"			output mode ("Fill" or "Line")
t	0			output time step
var	"u_xy"			variable to be output
xs	-1e+38			output x-coordinate range start (in m)
xe	+1e+38			output x-coordinate range end   (in m)
ys	-1e+38			output y-coordinate range start (in m)
ye	+1e+38			output y-coordinate range end   (in m)
zs	-1e+38			output z-coordinate range start (in m)
ze	+1e+38			output z-coordinate range end   (in m)

Usage
=====
This script draws NCL contour plots from two-dimensional cross-sections of 
NetCDF data produced by PALM. Instantaneous or time-averaged xy-, xz-, yz- or 
3D-data can be used with this script.

The sectional plane has neither a default orientation nor a default position.
Both must be specified together using the coordinate range parameters:
- For xy cross-sections specify zs and ze (with zs=za).
- For xz cross-sections specify ys and ye (with ys=ya).
- For yz cross-sections specify xs and xe (with xs=xa).

The remaining coordinate range parameters can optionally be used to restrict 
the output coordinate range.

By default, only screen output is produced. Additional file output is optional
and requires to specify the parameter fo. This will create three files: fo.pdf,
fo.eps and fo.ps.

Input and output files can optionally be preceeded by an input and output
directory di and d, respectively. If not specified, this scripts expects the
input file to reside in the current directory.

The contours can be drawn either in "Fill" (default) or "Line" mode.