00001 //# DerivedMC.h: Derived MS and CalTable columns 00002 //# Copyright (C) 2010 00003 //# Associated Universities, Inc. Washington DC, USA. 00004 //# 00005 //# This library is free software; you can redistribute it and/or modify it 00006 //# under the terms of the GNU Library General Public License as published by 00007 //# the Free Software Foundation; either version 2 of the License, or (at your 00008 //# option) any later version. 00009 //# 00010 //# This library is distributed in the hope that it will be useful, but WITHOUT 00011 //# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 00012 //# FITNESS FOR A PARTICULAR PURPOSE. See the GNU Library General Public 00013 //# License for more details. 00014 //# 00015 //# You should have received a copy of the GNU Library General Public License 00016 //# along with this library; if not, write to the Free Software Foundation, 00017 //# Inc., 675 Massachusetts Ave, Cambridge, MA 02139, USA. 00018 //# 00019 //# Correspondence concerning AIPS++ should be addressed as follows: 00020 //# Internet email: aips2-request@nrao.edu. 00021 //# Postal address: AIPS++ Project Office 00022 //# National Radio Astronomy Observatory 00023 //# 520 Edgemont Road 00024 //# Charlottesville, VA 22903-2475 USA 00025 //# 00026 //# $Id$ 00027 00028 #ifndef DERIVEDMSCAL_DERIVEDMC_H 00029 #define DERIVEDMSCAL_DERIVEDMC_H 00030 00031 #include <casacore/casa/aips.h> 00032 #include <casacore/derivedmscal/DerivedMC/DerivedMSCal.h> 00033 00034 namespace casacore { //# NAMESPACE CASACORE - BEGIN 00035 00036 // <module> 00037 // 00038 // <summary> 00039 // Derived MS and CalTable columns 00040 // </summary> 00041 00042 // <prerequisite> 00043 // <li> <linkto module="MeasurementSets:description">MeasurementSets</linkto> module 00044 // </prerequisite> 00045 // 00046 // <reviewed reviewer="" date="" demos=""> 00047 // </reviewed> 00048 00049 // <etymology> 00050 // Class to handle derived columns in an MS or CalTable. 00051 // </etymology> 00052 // 00053 // <synopsis> 00054 // A MeasurementSet or CalTable can be extended with virtual columns to 00055 // be able to use hourangle, azimuth/elevation, parallactic angle, and UVW 00056 // as if they were stored in the table using the DerivedMSCal virtual column 00057 // engine. Such columns have a fixed name, otherwise the engine cannot handle 00058 // them. The class description of the engine shows which columns can be handled 00059 // and gives an example how to add them. 00060 // 00061 // Class UDFMSCal contains TaQL user defined functions for these virtual 00062 // columns. In this way the columns do not need to be added to the table, 00063 // but can be used directly in a TaQL command. For example: 00064 // <srcblock> 00065 // select from my.ms where derivedmscal.ha1() > 10deg 00066 // </srcblock> 00067 // to select the rows where the hourangle of ANTENNA1 fulfills the condition. 00068 // If HA1 was added as a virtual column (which is more intrusive), the 00069 // command could look like: 00070 // <srcblock> 00071 // select from my.ms where HA1 > 10deg 00072 // </srcblock> 00073 // 00074 // UVW coordinates are already stored in an MS, but the virtual UVW_J2000 00075 // column makes it possible to calculate them on the fly. 00076 // 00077 // An MS or CalTable can be created with one or more of these columns or they 00078 // can be added later using 'DerivedMSCal' as their data manager. 00079 // A column can, of course, also be removed. If all these columns are removed, 00080 // the Table System will also remove the data manager from the table. 00081 // 00082 // The derivedmscal library can be used in two ways: 00083 // <ol> 00084 // <li> It needs to be linked in if the DerivedMSCal class is used. This 00085 // mode will probably be used rarely. 00086 // <li> It will be loaded dynamically when a table is opened with columns 00087 // using this data manager, when a column is added to a table using 00088 // this data manager by name (thus without an object), or when 00089 // such a TaQL user defined function is used. 00090 // </ol> 00091 // <note> For the second reason above it is important that the library 00092 // and the other casacore libraries are built shared. 00093 // </note> 00094 // </synopsis> 00095 // 00096 // <motivation> 00097 // It is very handy to be able to use a column like PA in software that can 00098 // deal with various table columns (e.g. TaQL, TablePlot, pyrap). 00099 // </motivation> 00100 00101 //# <todo asof="1997/02/01"> 00102 //# </todo> 00103 00104 // </module> 00105 00106 00107 } //# NAMESPACE CASACORE - END 00108 00109 #endif