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NhlNDCToData

Converts normalized device coordinates (NDCs) into data coordinates.

Prototype

	procedure NhlNDCToData (
		plot  [1] : graphic,  
		x_in  [*] : float,    
		y_in  [*] : float,    
		x_out [*] : float,    
		y_out [*] : float     
	)

Arguments

plot

A plot object that can be created by using one of the many gsn plotting functions, or by calling the NCL create language construct.

x_in
y_in

One-dimensional arrays of x and y normalized device coordinates (NDCs). They must be the same length.

x_out
y_out

(output)
One-dimensional arrays of the same size as x_in and y_in. These will contain the x and y data coordinate output values. For map plots, x_out corresponds to longitude values, and y_out corresponds to latitude values.

Description

The NhlNDCToData procedure uses the built-in transformation mapping feature of NCL plot objects to map NDCs (normalized device coordinates) into data coordinates.

The NhlNDCToData procedure maps coordinate pairs from x_in and y_in and places the results in the corresponding elements of x_out and y_out, respectively. Both x_out and y_out can be the same variables as x_in and y_in.

When the data coordinates are outside the NDC viewport specified in the plot, a missing value is placed in both of the corresponding indexes in the output arrays. The missing value chosen is either the x_in missing value, y_in missing value, or a system default.

Note: this procedure is identical to the ndctodata procedure, and we encourage the use of ndctodata instead (saves having to type longer names and capital letters).

See Also

ndctodata, datatondc

Examples

See the examples for ndctodata.