NCL Home > Documentation > Graphics > Graphical Interfaces

gsn_blank_plot

Draws a blank plot.

Prototype

load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_code.ncl"

	function gsn_blank_plot (
		wks [1] : graphic,  
		res [1] : logical   
	)

	return_val [1] :  graphic

Arguments

wks

A Workstation identifier. The identifier is one returned either from calling gsn_open_wks or calling create to create a Workstation object.

res

A variable containing an optional list of plot resources, attached as attributes. Set to True if you want the attached attributes to be applied, and False if you either don't have any resources to set, or you don't want the resources applied.

Return value

A scalar id of the plot created is returned. This is useful if you want to use setvalues to change some plot options after this function has been called.

Description

This function creates and draws a blank plot with tickmarks. By default, the axes will go from 0.0 to 1.0. To change this, you can set trXMinF, trXMaxF, trYMinF, and/or trYMaxF.

You can also set any of the Tickmark resources to control their appearance.

This function useful if you need to further annotate an existing plot by doing something additional with tickmarks. You can then overlay it on your existing plot. It is also useful if you just need a blank plot in order to draw some primitives (polylines, polymarkers, polygons).

The frame is not automatically advanced for this function, so set gsnFrame to True if you need this. To maximize the area that the plot is drawn in, set the special resource gsnMaximize to True.

Examples

For some application examples, see:

"tm_11.ncl" (view example)

Here's a simple example that creates a default "blank" plot.

load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_code.ncl"

begin
  wks = gsn_open_wks("x11","blank")

  res = True

  res@gsnMaximize = True
  res@gsnFrame    = True    ; The frame is not advanced by default.

  plot = gsn_blank_plot(wks,res)

end