Provided by: libncarg-dev_6.3.0-6build1_amd64 NAME

c_shgetnp - find the nearest points to a specified point in 3-space

FUNCTIONPROTOTYPE

int c_shgetnp(float, float, float, int, float *, float *, float *,
int, int *);

SYNOPSIS

int c_shgetnp (px, py, pz, n, x[], y[], z[], iflag, ier );

DESCRIPTION

px          (float)  The  X coordinate value for a point P whose nearest neighbor is to be
found.

py          (float) The Y coordinate value for a point P whose nearest neighbor is  to  be
found.

pz          (float)  The  Z coordinate value for a point P whose nearest neighbor is to be
found.

n           (int) The number of input data points, n > 1.

x           (float) An array of length n containing the X coordinate values for the  input
data points.

y           (float)  An array of length n containing the Y coordinate values for the input
data points.

z           (float) An array of length n containing the Z coordinate values for the  input
data points.

iflag       (int)  A  flag  that equals 0 if this is the first call to this subroutine for
the given dataset and equals 1 otherwise.

ier         (pointer to int) An error return value.  If *ier is returned  as  0,  then  no
errors  were  detected.  If  *ier  is  non-zero, then look at the man page for
shgrid_errors for details.

USAGE

c_shgetnp is called to find the nearest point to a specified point in 3-space.  Successive
calls  to  c_shgetnp will determine the point nearest the specified point exclusive of the
points found in previous calls, i.e. successive calls can be used to find  the  N  nearest
points for any N between one and the maximum number of points in the input dataset.

c_shgetnp  returns  an integer, say np, such that (x[np],y[np],z[np]) is the nearest input
data point to P. np = -1 if *ier is not zero. On successive calls to this  function  after
the first (that is when iflag=1) you can find the Mth closest point to (px,py,pz) with the
Mth call.

ACCESS

To use c_shgetnp, load the NCAR Graphics library ngmath.

SEEALSO

shgetnp, c_shgrid, c_shseti, c_shgeti, shgrid_params.

Complete documentation for Sh is available at URL
http://ngwww.ucar.edu/ngdoc/ng/ngmath/shgrid/shhome.html