irreg2map - Convert irregular data to uniform field

Name

	irreg2map - Convert irregular data to uniform field

Author

INFORMATION
	John Tee
	AVS Inc. Consultant
	17 Dawnay Road, Great Bookham, Leatherhead, Surrey KT23 4PE, UK
	Tel/Fax (+44) 0372 459214

Summary

	Name	irreg2map
	Type	Mapper
	Inputs	input - 	field 2D irregular float REQUIRED
	Outputs	output - 	field 2D 2-space uniform byte
	Parameters
	Name		Type		Default	Min	Max
	Row/Col		choice		Col	Row!Col
	Row/Col No	idial		0	0	500
	Max Int		dial		50.00	 0.00	100.00
	Min Int		dial		50.00	 0.00	100.00
	X start		typein_real	0	-1	1
	Y start		typein_real	0	-1	1
	X stop		typein_real	1	-1	1
	Y stop		typein_real	1       -1      1
	X step		dial		.1	.01	1.
	Y step		dial		.1      .01     1.

Description

	IRREG2MAP is intended for applications in which data from scattered
sensors is stored in irregular fields, and needs to be displayed, or processed,
as uniform data.  In particular, a time series of measurements may be stored
in a 2D irregular field, with the one compute dimension representing time,
and the other dimension the data values recorded at that time.  For the data
to be displayed in the Image Viewer, or as a texture map in the Geometry
Viewer, this module is needed to create the uniform field required.
	IRREG2MAP produces a uniform byte field in which the pixels are set
to zero, except where data from a selected row or column of the input field
exists.  The resolution of the output field is determined by the X_start,
Y_start, X_stop, Y_stop, X_step and Y_step parameters.  The module ignores
any Z data in a 3-space field.  The X and Y limits determine the range of
coordinates, present in the input field, that are mapped into the output
field.  Values which fall outside the range of coordinates selected for the

Output

field are ignored.
	The range of intensities in the output field is, by default, set
automatically to match the range of intensities in the whole of the input
field. (Note that this is not the same as auto-scaling each output field.)
Manual adjustment is provided by the Max Int and Min Int dials, which set the
value of the input data which is mapped to 255 and 0 respectively.  Out-of-
range values are set to 0 or 255 as appropriate.

Inputs

	input - field 2D 2-space irregular float

Parameters

Row/Column (choice)  Selection of whether row or column contains the "image"
Row/Col No (idial)  Column or Row index of input field to process
Max Int (dial)  Value in input field mapped to 255 in output
Min Int (dial)  Value in input field mapped to 0 in output
X step  (dial)  Increment in X-coordinates corresponding to 1 pixel in output
Y step  (dial)  Increment in Y-coordinates corresponding to 1 pixel in output
X start (typein_real)	X-coordinate in input field mapped to left of output
Y start (typein_real)	Y-coordinate in input field mapped to top of output
X stop  (typein_real)	X-coordinate in input field mapped to right of output
Y stop  (typein_real)   Y-coordinate in input field mapped to bottom of output
OUTPUTS
	output - field 2D 2-space uniform byte

Example networks

LIMITATIONS
	There is no reason why IRREG2MAP need take only float input data.
The output field is byte for use in the Viewers, but other data types could
be allowed.
	The module does not take special action if two or more data values
are mapped to the same output pixel.  As a result, the value in the output
pixel is that from the larger coordinate in compute space.
	For displaying time-dependent measurements from static sensors, the
method of storing the data as an irregular field is inefficient, as each set
of coordinates in the row direction is identical.  A separate field containing
the coordinates for a column could be used in this case, in conjunction with
a uniform input data field, but the generality of the solution would be lost.

Related modules

See also