casa6

//# SpectralImageUtil.cc: Spectral Image Utilities

//# Copyright (C) 2013

//# Associated Universities, Inc. Washington DC, USA.

//#

//# This library is free software; you can redistribute it and/or modify it

//# under the terms of the GNU Library General Public License as published by

//# the Free Software Foundation; either version 2 of the License, or (at your

//# option) any later version.

//#

//# This library is distributed in the hope that it will be useful, but WITHOUT

//# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

//# FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Library General Public

//# License for more details.

//#

//# You should have received a copy of the GNU Library General Public License

//# along with this library; if not, write to the Free Software Foundation,

//# Inc., 675 Massachusetts Ave, Cambridge, MA 02139, USA.

//#

//# Correspondence concerning AIPS++ should be adressed as follows:

//#        Internet email: aips2-request@nrao.edu.

//#        Postal address: AIPS++ Project Office

//#                        National Radio Astronomy Observatory

//#                        520 Edgemont Road

//#                        Charlottesville, VA 22903-2475 USA

//#

//#

//# $Id$

​

​

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template <typename T>  casacore::SubImage<T>* SpectralImageUtil::getChannel(casacore::ImageInterface<T>& theIm, casacore::Int beginchannel, casacore::Int endchannel, casacore::Bool writeAccess){

    casacore::CoordinateSystem csys=theIm.coordinates();

    if(endchannel<0 )

      endchannel=beginchannel;

    if(beginchannel > endchannel){ 

      casacore::Int temp=endchannel;

      endchannel=beginchannel;

      beginchannel=temp;

    }

    casacore::Int spectralIndex=casacore::CoordinateUtil::findSpectralAxis(csys);

    casacore::IPosition blc(theIm.shape());

    casacore::IPosition trc(theIm.shape());

    blc-=blc; //set all values to 0

    trc=theIm.shape();

    trc-=1; // set trc to image size -1

    if(beginchannel > trc[spectralIndex] || beginchannel <0 || endchannel >  trc[spectralIndex] )

      throw(casacore::AipsError("Channel requested does not exist"));

    blc[spectralIndex]=beginchannel;

    trc[spectralIndex]=endchannel;

    casacore::Slicer sl(blc, trc, casacore::Slicer::endIsLast);

    casacore::SubImage<T> * imageSub=new casacore::SubImage<T>(theIm, sl, writeAccess);

    return imageSub;

  };

​

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