SURFLIB_FILL_GRID - Populate grid with data points corresponding to position

Description:

Given an array of I,J coordinates associated with data values, this routine places each data point onto the rectangular grid and the position in the data array into a corresponding grid. Grid is of size (NX,NY,NMAX) and each data point is placed into a different layer (up to NMAX) for each I,J. We already know the value of NMAX since the output array has been pre-allocated.

Invocation:

CALL SURFLIB_FILL_GRID (N_PTS, NX, NY, NMAX, OFFSET, IN_DATA, IN_QUALITY, BADBIT, IJ, GRID, BINS, BIN_POS, STATUS )

Arguments:

N_PTS = INTEGER (Given)

Number of I,J pairs supplied

NX = INTEGER (Given)

Size of X dimension

NY = INTEGER (Given)

Size of Y dimension

NMAX = INTEGER (Given)

Maximum value allowed for third dimension of BINS

OFFSET = INTEGER (Given)

This is the offset in the IJ data array. Not used for IJ itself (Since this is added to the pointer of the input array if needed) in this array but is added onto each of the values placed into the BIN_POS array so that we can keep track of the input data without using a further two pieces of information.

IN_DATA(N_PTS) = REAL (Given)

Input data

IN_QUALITY(N_PTS) = BYTE (Given)

Input quality

BADBIT = BYTE (Given)

Bad bits mask for quality array

IJ ( 2, N_PTS ) = INTEGER (Given)

Positions of each point (I,J) in output grid for each N_PTS

GRID (NX, NY) = INTEGER (Given & Returned)

Scratch space for keeping track of the number of points added into each I,J

BINS(NX, NY, NMAX) = REAL (Given & Returned)

The data stored in relation to its position

BIN_POS (NX, NY, NMAX) = INTEGER (Given & Returned)

The position in the input data arrays associated with each data point in BINS

STATUS = INTEGER (Given & Returned)

Global Status

Notes:

• GRID is not initialised by this routine since it is incremented each time a point is placed in BINS

• BINS and BIN_POS are not initialised here but should be filled with bad before this routine is first called.

• a status of SAI__WARN is returned if the indices lie outside the model area. It is up to the calling routine to decide whether to halt.

Copyright

Copyright ©1995,1996,1997,1998,1999 Particle Physics and Astronomy Research Council. All Rights Reserved.