function [ cThis ] = reduce_spatial( this, newCoordinates, varargin )
%
% This function is used to reduce the spatial sampling from the current
% directions. This is done with a findnearest search. For a reduction to
% interpolated values use interp
%
% INPUT:
%
%
% OUTPUT:
%
%
%
% Author: Jan-Gerrit Richter
% Version: 2017-11-23
oldCoords = this.getEar('L').channelCoordinates;
% if the desired sampling has more points, its probably unfeasable with
% findnearest search. Abort
if oldCoords.nPoints < newCoordinates.nPoints
error('There are more points in the wanted sampling than are available. You probably want the interp function');
end
% the new coords should have the same radius as the old ones to reduce
% errors
newCoordinates.r = mean(oldCoords.r);
% don't use the mex file to make use of bugfix as poles
% oldCoords = oldCoords.build_search_database;
newIndex = oldCoords.findnearest(newCoordinates);
% calculate all distances from the wanted points to the found points
pointDistances = getVectorLength(newCoordinates,oldCoords.n(newIndex));
% calculate the distance between two neighboring points of the new sampling
newSamplingDistance = getVectorLength(newCoordinates.n(1),newCoordinates.n(2));
% the maximum of the found points should always be smaller
if max(pointDistances) > newSamplingDistance
ita_verbose_info('The found points are further apart than the sampling allows. Something is wrong',0)
end
cThis = this.direction(newIndex);
end
function length = getVectorLength(pointsA, pointsB)
pointsA.r = pointsB.r;
vector = pointsA - pointsB;
length = sqrt(vector.x.^2 + vector.y.^2 + vector.z.^2);
end