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density

PURPOSE ^

DENSITY - Calculates the spatial density of grid points around a

SYNOPSIS ^

function dens = density( tg, gd, r, xy, type )

DESCRIPTION ^

 DENSITY - Calculates the spatial density of grid points around a
 certain set of points for each timestep.

 Usage: dens = density( totalGrid, gooddata, radius, coord_pts )

 totalGrid is a 2-column set of coordinate points where data is located.  

 gooddata is a matrix where each row corresponds to a grid point (point
 in totalGrid) and each column is a timestep.  Grid points and time steps for
 which data is present should be represented by a 1, bad data by a zero.
 If gooddata=[] (i.e. is empty), then a one column matrix of ones with the
 same number of elements as grid points in totalGrid will be used.

 radius is a distance in Km around each grid point to look for other data
 points.  It can be a scalar, in which case a single distance is used, or
 it can be a vector with as many elements as points in coord_pts.

 coord_pts is a two column matrix of the coordinates of the points at which
 the density is to be determined.  It should be in the same units as
 totalGrid (i.e. either Km or lon,lat).  If this argument is absent, then
 totalGrid is used.

 type is a string indicating the units of totalGrid and coord_pts.  It
 can be either 'lon,lat' or 'km' (must be exact). Defaults to 'lon,lat'.

 NOTE that this function requires the lonlat2km function from Mike Cook's
 HFradarmap toolbox if lon,lat coordinates are used.

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     $Id: density.m,v 1.2 2006-08-01 18:16:09 dmk Exp $    

 Copyright (C) 2006 David M. Kaplan
 Licence: GPL

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CROSS-REFERENCE INFORMATION ^

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