If parameter SHAPE is set TRUE, a 2 or 3 dimensional NDF is created in which the spatial position of each data value is read from the catalogue columns specified using parameters COLX, COLY and COLZ. The NDF is formed by binning the catalogue values into a grid of equally sized rectangular cells, the dimensions of each cell being given by parameter BOX. Each pixel in the output NDF corresponds to one of these cells. The data values for the cell are formed by combining together the COLDAT values of all input positions which fall within the cell, using the method specified by the parameter METHOD.
If parameter SHAPE is set FALSE, a 1D NDF is created in which the spatial position of each data value is ignored. The data values are just copied into the 1D NDF in the same order that they appear in the input catalogue. That is, the first value in the catalogue becomes pixel 1, the seconds catalogue value becomes pixel 2, etc. This avoids any binning of the data values, and is useful if applications which do not use spatial information (such as the KAPPA applications STATS, HISTOGRAM, etc) are to be used.