Index: trunk/src/series/civ_series.m
===================================================================
--- trunk/src/series/civ_series.m	(revision 937)
+++ trunk/src/series/civ_series.m	(revision 938)
@@ -890,5 +890,5 @@
         if isempty(errormsg)
             disp([ncfile_out ' written'])
-            [success,msg] = fileattrib(ncfile_out ,'+w','g');% allow writing access for the group of users, recursively in the folder
+            %[success,msg] = fileattrib(ncfile_out ,'+w','g');% done in struct2nc
         else
             disp(errormsg)
Index: trunk/src/series/merge_proj.m
===================================================================
--- trunk/src/series/merge_proj.m	(revision 937)
+++ trunk/src/series/merge_proj.m	(revision 938)
@@ -252,4 +252,8 @@
     %%%%%%%%%%%%%%%% loop on field indices %%%%%%%%%%%%%%%%
 tstart=tic; %used to record the computing time
+CheckOverwrite=1;%default
+if isfield(Param,'CheckOverwrite')
+    CheckOverwrite=Param.CheckOverwrite;
+end
 for index=1:NbField
         update_waitbar(WaitbarHandle,index/NbField)
@@ -258,4 +262,28 @@
         return
     end
+    
+     %% generating the name of the merged field
+    i1=i1_series{1}(index);
+    if ~isempty(i2_series{end})
+        i2=i2_series{end}(index);
+    else
+        i2=i1;
+    end
+    j1=1;
+    j2=1;
+    if ~isempty(j1_series{1})
+        j1=j1_series{1}(index);
+        if ~isempty(j2_series{end})
+            j2=j2_series{end}(index);
+        else
+            j2=j1;
+        end
+    end
+    OutputFile=fullfile_uvmat(RootPath{1},OutputDir,RootFileOut,FileExtOut,NomTypeOut,i1,i2,j1,j2);
+    if ~CheckOverwrite && exist(OutputFile,'file')
+            disp(['existing output file ' OutputFile ' already exists, skip to next field'])
+            continue% skip iteration if the mode overwrite is desactivated and the result file already exists
+    end
+        
     %%%%%%%%%%%%%%%% loop on views (input lines) %%%%%%%%%%%%%%%%
     Data=cell(1,NbView);%initiate the set Data
@@ -268,4 +296,5 @@
             return
         end
+        
         ListVar=Data{iview}.ListVarName;
         for ilist=1:numel(ListVar)
@@ -325,23 +354,5 @@
     end
 
-    %% generating the name of the merged field
-    i1=i1_series{1}(index);
-    if ~isempty(i2_series{end})
-        i2=i2_series{end}(index);
-    else
-        i2=i1;
-    end
-    j1=1;
-    j2=1;
-    if ~isempty(j1_series{1})
-        j1=j1_series{1}(index);
-        if ~isempty(j2_series{end})
-            j2=j2_series{end}(index);
-        else
-            j2=j1;
-        end
-    end
-    OutputFile=fullfile_uvmat(RootPath{1},OutputDir,RootFileOut,FileExtOut,NomTypeOut,i1,i2,j1,j2);
-
+  
     %% recording the merged field
     if strcmp(FileExtOut,'.png')    %output as image
Index: trunk/src/series/merge_proj_polar.m
===================================================================
--- trunk/src/series/merge_proj_polar.m	(revision 938)
+++ trunk/src/series/merge_proj_polar.m	(revision 938)
@@ -0,0 +1,543 @@
+%'merge_proj': concatene several fields from series, can project them on a regular grid in phys coordinates
+%------------------------------------------------------------------------
+% function ParamOut=merge_proj(Param)
+%------------------------------------------------------------------------
+%%%%%%%%%%% GENERAL TO ALL SERIES ACTION FCTS %%%%%%%%%%%%%%%%%%%%%%%%%%%
+%
+%OUTPUT
+% ParamOut: sets options in the GUI series.fig needed for the function
+%
+%INPUT:
+% In run mode, the input parameters are given as a Matlab structure Param copied from the GUI series.
+% In batch mode, Param is the name of the corresponding xml file containing the same information
+% when Param.Action.RUN=0 (as activated when the current Action is selected
+% in series), the function ouput paramOut set the activation of the needed GUI elements
+%
+% Param contains the elements:(use the menu bar command 'export/GUI config' in series to 
+% see the current structure Param)
+%    .InputTable: cell of input file names, (several lines for multiple input)
+%                      each line decomposed as {RootPath,SubDir,Rootfile,NomType,Extension}
+%    .OutputSubDir: name of the subdirectory for data outputs
+%    .OutputDirExt: directory extension for data outputs
+%    .Action: .ActionName: name of the current activated function
+%             .ActionPath:   path of the current activated function
+%             .ActionExt: fct extension ('.m', Matlab fct, '.sh', compiled   Matlab fct
+%             .RUN =0 for GUI input, =1 for function activation
+%             .RunMode='local','background', 'cluster': type of function  use
+%             
+%    .IndexRange: set the file or frame indices on which the action must be performed
+%    .FieldTransform: .TransformName: name of the selected transform function
+%                     .TransformPath:   path  of the selected transform function
+%    .InputFields: sub structure describing the input fields withfields
+%              .FieldName: name(s) of the field
+%              .VelType: velocity type
+%              .FieldName_1: name of the second field in case of two input series
+%              .VelType_1: velocity type of the second field in case of two input series
+%              .Coord_y: name of y coordinate variable
+%              .Coord_x: name of x coordinate variable
+%    .ProjObject: %sub structure describing a projection object (read from ancillary GUI set_object)
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+%=======================================================================
+% Copyright 2008-2016, LEGI UMR 5519 / CNRS UGA G-INP, Grenoble, France
+%   http://www.legi.grenoble-inp.fr
+%   Joel.Sommeria - Joel.Sommeria (A) legi.cnrs.fr
+%
+%     This file is part of the toolbox UVMAT.
+%
+%     UVMAT is free software; you can redistribute it and/or modify
+%     it under the terms of the GNU General Public License as published
+%     by the Free Software Foundation; either version 2 of the license,
+%     or (at your option) any later version.
+%
+%     UVMAT 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 General Public License (see LICENSE.txt) for more details.
+%=======================================================================
+
+function ParamOut=merge_proj_polar(Param)
+
+%% set the input elements needed on the GUI series when the function is selected in the menu ActionName or InputTable refreshed
+if isstruct(Param) && isequal(Param.Action.RUN,0)
+    ParamOut.AllowInputSort='off';% allow alphabetic sorting of the list of input file SubDir (options 'off'/'on', 'off' by default)
+    ParamOut.WholeIndexRange='off';% prescribes the file index ranges from min to max (options 'off'/'on', 'off' by default)
+    ParamOut.NbSlice='off'; %nbre of slices ('off' by default)
+    ParamOut.VelType='one';% menu for selecting the velocity type (options 'off'/'one'/'two',  'off' by default)
+    ParamOut.FieldName='one';% menu for selecting the field (s) in the input file(options 'off'/'one'/'two', 'off' by default)
+    ParamOut.FieldTransform = 'on';%can use a transform function
+    ParamOut.TransformPath=fullfile(fileparts(which('uvmat')),'transform_field');% path to transform functions (needed for compilation only)
+    ParamOut.ProjObject='on';%can use projection object(option 'off'/'on',
+    ParamOut.Mask='on';%can use mask option   (option 'off'/'on', 'off' by default)
+    ParamOut.OutputDirExt='.mproj';%set the output dir extension
+    ParamOut.OutputFileMode='NbInput';% '=NbInput': 1 output file per input file index, '=NbInput_i': 1 file per input file index i, '=NbSlice': 1 file per slice
+      %check the input files
+    ParamOut.CheckOverwriteVisible='on'; % manage the overwrite of existing files (default=1)
+    first_j=[];
+    if isfield(Param.IndexRange,'first_j'); first_j=Param.IndexRange.first_j; end
+    PairString='';
+    if isfield(Param.IndexRange,'PairString'); PairString=Param.IndexRange.PairString; end
+    [i1,i2,j1,j2] = get_file_index(Param.IndexRange.first_i,first_j,PairString);
+    FirstFileName=fullfile_uvmat(Param.InputTable{1,1},Param.InputTable{1,2},Param.InputTable{1,3},...
+        Param.InputTable{1,5},Param.InputTable{1,4},i1,i2,j1,j2);
+    if ~exist(FirstFileName,'file')
+        msgbox_uvmat('WARNING',['the first input file ' FirstFileName ' does not exist'])
+    elseif isequal(size(Param.InputTable,1),1) && ~isfield(Param,'ProjObject')
+        msgbox_uvmat('WARNING','You may need a projection object of type plane for merge_proj')
+    end
+    return
+end
+
+%%%%%%%%%%%% STANDARD PART (DO NOT EDIT) %%%%%%%%%%%%
+ParamOut=[]; %default output
+RUNHandle=[];
+WaitbarHandle=[];
+%% read input parameters from an xml file if input is a file name (batch mode)
+checkrun=1;
+if ischar(Param)
+    Param=xml2struct(Param);% read Param as input file (batch case)
+    checkrun=0;
+else
+    hseries=findobj(allchild(0),'Tag','series');
+    RUNHandle=findobj(hseries,'Tag','RUN');%handle of RUN button in GUI series
+    WaitbarHandle=findobj(hseries,'Tag','Waitbar');%handle of waitbar in GUI series
+end
+
+%% define the directory for result file (with path=RootPath{1})
+OutputDir=['three_cameras' Param.OutputDirExt];% subdirectory for output files
+
+if ~isfield(Param,'InputFields')
+    Param.InputFields.FieldName='';
+end
+
+%% root input file type
+RootPath=Param.InputTable(:,1);
+RootFile=Param.InputTable(:,3);
+SubDir=Param.InputTable(:,2);
+NomType=Param.InputTable(:,4);
+FileExt=Param.InputTable(:,5);
+[filecell,i1_series,i2_series,j1_series,j2_series]=get_file_series(Param);
+%%%%%%%%%%%%
+% The cell array filecell is the list of input file names, while
+% filecell{iview,fileindex}:
+%        iview: line in the table corresponding to a given file series
+%        fileindex: file index within  the file series, 
+% i1_series(iview,ref_j,ref_i)... are the corresponding arrays of indices i1,i2,j1,j2, depending on the input line iview and the two reference indices ref_i,ref_j 
+% i1_series(iview,fileindex) expresses the same indices as a 1D array in file indices
+%%%%%%%%%%%%
+% NbSlice=1;%default
+% if isfield(Param.IndexRange,'NbSlice')&&~isempty(Param.IndexRange.NbSlice)
+%     NbSlice=Param.IndexRange.NbSlice;
+% end
+NbView=numel(i1_series);%number of input file series (lines in InputTable)
+NbField_j=size(i1_series{1},1); %nb of fields for the j index (bursts or volume slices)
+NbField_i=size(i1_series{1},2); %nb of fields for the i index
+NbField=NbField_j*NbField_i; %total number of fields
+
+%% determine the file type on each line from the first input file 
+ImageTypeOptions={'image','multimage','mmreader','video'};
+NcTypeOptions={'netcdf','civx','civdata'};
+for iview=1:NbView
+    if ~exist(filecell{iview,1}','file')
+        disp_uvmat('ERROR',['the first input file ' filecell{iview,1} ' does not exist'],checkrun)
+        return
+    end
+    [FileInfo{iview},MovieObject{iview}]=get_file_info(filecell{iview,1});
+    FileType{iview}=FileInfo{iview}.FileType;
+    CheckImage{iview}=~isempty(find(strcmp(FileType{iview},ImageTypeOptions)));% =1 for images
+    if CheckImage{iview}
+        ParamIn{iview}=MovieObject{iview};
+    else
+        ParamIn{iview}=Param.InputFields;
+    end
+    CheckNc{iview}=~isempty(find(strcmp(FileType{iview},NcTypeOptions)));% =1 for netcdf files
+    if ~isempty(j1_series{iview})
+        frame_index{iview}=j1_series{iview};
+    else
+        frame_index{iview}=i1_series{iview};
+    end
+end
+if NbView >1 && max(cell2mat(CheckImage))>0 && ~isfield(Param,'ProjObject')
+    disp_uvmat('ERROR','projection on a common grid is needed to concatene images: use a Projection Object of type ''plane'' with ProjMode=''interp_lin''',checkrun)
+    return
+end
+
+%% calibration data and timing: read the ImaDoc files
+[XmlData,NbSlice_calib,time,errormsg]=read_multimadoc(RootPath,SubDir,RootFile,FileExt,i1_series,i2_series,j1_series,j2_series);
+if size(time,1)>1
+    diff_time=max(max(diff(time)));
+    if diff_time>0 
+        disp_uvmat('WARNING',['times of series differ by (max) ' num2str(diff_time) ': the mean time is chosen in result'],checkrun)
+    end   
+end
+if ~isempty(errormsg)
+    disp_uvmat('WARNING',errormsg,checkrun)
+end
+time=mean(time,1); %averaged time taken for the merged field
+
+%% coordinate transform or other user defined transform
+transform_fct='';%default fct handle
+if isfield(Param,'FieldTransform')&&~isempty(Param.FieldTransform.TransformName)
+        currentdir=pwd;
+        cd(Param.FieldTransform.TransformPath)
+        transform_fct=str2func(Param.FieldTransform.TransformName);
+        cd (currentdir)
+        if isfield(Param,'TransformInput')
+            for iview=1:NbView
+            XmlData{iview}.TransformInput=Param.TransformInput;
+            end
+        end       
+end
+%%%%%%%%%%%% END STANDARD PART  %%%%%%%%%%%%
+ % EDIT FROM HERE
+
+%% check the validity of  input file types
+for iview=1:NbView
+    if ~isequal(CheckImage{iview},1)&&~isequal(CheckNc{iview},1)
+        disp_uvmat('ERROR','input set of input series: need  either netcdf either image series',checkrun)
+        return
+    end
+end
+
+%% output file type
+if min(cell2mat(CheckImage))==1 && (~Param.CheckObject || strcmp(Param.ProjObject.Type,'plane'))
+    FileExtOut='.png'; %image output (input and proj result = image)
+    for iview=1:NbView
+        BitDepth(iview)=FileInfo{iview}.BitDepth;
+    end
+    BitDepth=max(BitDepth);
+else
+    FileExtOut='.nc'; %netcdf output
+end
+if isempty(j1_series{1})
+    NomTypeOut='_1';
+else
+    NomTypeOut='_1_1';
+end
+%NomTypeOut=NomType;% output file index will indicate the first and last ref index in the series
+RootFileOut=RootFile{1};
+for iview=2:NbView
+    if ~strcmp(RootFile{iview},RootFile{1})
+        RootFileOut='mproj';
+        break
+    end
+end
+
+%% mask (TODO: case of multilevels)
+MaskData=cell(NbView,1);
+if Param.CheckMask
+    if ischar(Param.MaskTable)% case of a single mask (char chain)
+        Param.MaskTable={Param.MaskTable};
+    end
+    for iview=1:numel(Param.MaskTable)
+        if exist(Param.MaskTable{iview},'file')
+            [MaskData{iview},tild,errormsg] = read_field(Param.MaskTable{iview},'image');
+            if ~isempty(transform_fct) && nargin(transform_fct)>=2
+                MaskData{iview}=transform_fct(MaskData{iview},XmlData{iview});
+            end
+        end
+    end
+end
+
+%% Set field names and velocity types
+%use Param.InputFields for all views
+
+%% MAIN LOOP ON FIELDS
+%%%%%%%%%%%%% STANDARD PART (DO NOT EDIT) %%%%%%%%%%%%
+% for i_slice=1:NbSlice
+%     index_slice=i_slice:NbSlice:NbField;% select file indices of the slice
+%     NbFiles=0;
+%     nbmissing=0;
+
+    %%%%%%%%%%%%%%%% loop on field indices %%%%%%%%%%%%%%%%
+tstart=tic; %used to record the computing time
+CheckOverwrite=1;%default
+if isfield(Param,'CheckOverwrite')
+    CheckOverwrite=Param.CheckOverwrite;
+end
+for index=1:NbField
+        update_waitbar(WaitbarHandle,index/NbField)
+    if ~isempty(RUNHandle) && ~strcmp(get(RUNHandle,'BusyAction'),'queue')
+        disp('program stopped by user')
+        return
+    end
+    
+     %% generating the name of the merged field
+    i1=i1_series{1}(index);
+    if ~isempty(i2_series{end})
+        i2=i2_series{end}(index);
+    else
+        i2=i1;
+    end
+    j1=1;
+    j2=1;
+    if ~isempty(j1_series{1})
+        j1=j1_series{1}(index);
+        if ~isempty(j2_series{end})
+            j2=j2_series{end}(index);
+        else
+            j2=j1;
+        end
+    end
+    OutputFile=fullfile_uvmat(RootPath{1},OutputDir,RootFileOut,FileExtOut,NomTypeOut,i1,i2,j1,j2);
+    if ~CheckOverwrite && exist(OutputFile,'file')
+            disp(['existing output file ' OutputFile ' already exists, skip to next field'])
+            continue% skip iteration if the mode overwrite is desactivated and the result file already exists
+    end
+        
+    %%%%%%%%%%%%%%%% loop on views (input lines) %%%%%%%%%%%%%%%%
+    Data=cell(1,NbView);%initiate the set Data
+    timeread=zeros(1,NbView);
+    for iview=1:NbView
+        %% reading input file(s)      
+        [Data{iview},tild,errormsg] = read_field(filecell{iview,index},FileType{iview},ParamIn{iview},frame_index{iview}(index));
+        if ~isempty(errormsg)
+            disp_uvmat('ERROR',['ERROR in merge_proj/read_field/' errormsg],checkrun)
+            return
+        end
+        
+        ListVar=Data{iview}.ListVarName;
+        for ilist=1:numel(ListVar)
+            Data{iview}.(ListVar{ilist})=double(Data{iview}.(ListVar{ilist}));% transform all fields in double before all operations
+        end
+        % get the time defined in the current file if not already defined from the xml file
+        if ~isempty(time) && isfield(Data{iview},'Time')
+            timeread(iview)=Data{iview}.Time;
+        end
+        if ~isempty(NbSlice_calib)
+            Data{iview}.ZIndex=mod(i1_series{iview}(index)-1,NbSlice_calib{iview})+1;%Zindex for phys transform
+        end
+        
+        %% transform the input field (e.g; phys) if requested (no transform involving two input fields)
+        if ~isempty(transform_fct)
+            if nargin(transform_fct)>=2
+                Data{iview}=transform_fct(Data{iview},XmlData{iview});
+            else
+                Data{iview}=transform_fct(Data{iview});
+            end
+        end
+        
+        %% calculate tps coefficients if needed
+        check_proj_tps= 1;
+        Data{iview}=tps_coeff_field(Data{iview},check_proj_tps);
+        
+        %% projection on object (gridded plane)
+        if Param.CheckObject
+            [Data{iview},errormsg]=proj_field(Data{iview},Param.ProjObject);
+            if ~isempty(errormsg)
+                disp_uvmat('ERROR',['ERROR in merge_proge/proj_field: ' errormsg],checkrun)
+                return
+            end
+        end
+        
+        %% mask
+        if Param.CheckMask && ~isempty(MaskData{iview})
+             [Data{iview},errormsg]=mask_proj(Data{iview},MaskData{iview});
+        end
+    end
+    %%%%%%%%%%%%%%%% END LOOP ON VIEWS %%%%%%%%%%%%%%%%
+
+    %% merge the NbView fields
+    [MergeData,errormsg]=merge_field(Data);
+    if ~isempty(errormsg)
+        disp_uvmat('ERROR',errormsg,checkrun);
+        return
+    end
+
+    %% time of the merged field: take the average of the different views
+    if ~isempty(time)
+        timeread=time(index);   
+    elseif ~isempty(find(timeread))% time defined from ImaDoc
+        timeread=mean(timeread(timeread~=0));% take average over times form the files (when defined)
+    else
+        timeread=index;% take time=file index 
+    end
+
+  
+    %% recording the merged field
+    if strcmp(FileExtOut,'.png')    %output as image
+        if BitDepth==8
+            imwrite(uint8(MergeData.A),OutputFile,'BitDepth',8)
+        else
+            imwrite(uint16(MergeData.A),OutputFile,'BitDepth',16)
+        end
+        if index==1
+            %write xml calibration file, using the first file
+            siz=size(MergeData.A);
+            npy=siz(1);
+            npx=siz(2);
+            if isfield(MergeData,'Coord_x') && isfield(MergeData,'Coord_y')
+                Rangx=MergeData.Coord_x;
+                Rangy=MergeData.Coord_y;
+            elseif isfield(MergeData,'AX')&& isfield(MergeData,'AY')
+                Rangx=[MergeData.AX(1) MergeData.AX(end)];
+                Rangy=[MergeData.AY(1) MergeData.AY(end)];
+            else
+                Rangx=[0.5 npx-0.5];
+                Rangy=[npy-0.5 0.5];%default
+            end
+            pxcmx=(npx-1)/(Rangx(2)-Rangx(1));
+            pxcmy=(npy-1)/(Rangy(1)-Rangy(2));
+            T_x=-pxcmx*Rangx(1)+0.5;
+            T_y=-pxcmy*Rangy(2)+0.5;
+            GeometryCal.CalibrationType='rescale';
+            GeometryCal.CoordUnit=MergeData.CoordUnit;
+            GeometryCal.focal=1;
+            GeometryCal.R=[pxcmx,0,0;0,pxcmy,0;0,0,1];
+            GeometryCal.Tx_Ty_Tz=[T_x T_y 1];
+            ImaDoc.GeometryCalib=GeometryCal;
+            t=struct2xml(ImaDoc);
+            t=set(t,1,'name','ImaDoc');
+            save(t,[fileparts(OutputFile) '.xml'])
+        end
+        
+    else   %output as netcdf files
+        MergeData.ListGlobalAttribute={'Conventions','Project','InputFile_1','InputFile_end','NbCoord','NbDim'};
+        MergeData.Conventions='uvmat';
+        MergeData.NbCoord=2;
+        MergeData.NbDim=2;
+        % time interval of PIV
+        Dt=[];
+        if isfield(Data{1},'Dt')&& isnumeric(Data{1}.Dt)
+            Dt=Data{1}.Dt;
+        end
+        for iview =2:numel(Data)
+            if ~(isfield(Data{iview},'Dt')&& isequal(Data{iview}.Dt,Dt))
+                Dt=[];%dt not the same for all fields
+            end
+        end
+        if ~isempty(timeread)
+            MergeData.ListGlobalAttribute=[MergeData.ListGlobalAttribute {'Time'}];
+            MergeData.Time=timeread;
+        end
+        % position of projection plane 
+        if isfield(Data{1},'ProjObjectCoord')&& isfield(Data{1},'ProjObjectAngle')
+            'test'
+            ProjObjectCoord=Data{1}.ProjObjectCoord;
+            ProjObjectAngle=Data{1}.ProjObjectAngle;
+            for iview =2:numel(Data)
+                if ~(isfield(Data{iview},'ProjObjectCoord')&& isequal(Data{iview}.ProjObjectCoord,ProjObjectCoord))...
+                        ||~(isfield(Data{iview},'ProjObjectAngle')&& isequal(Data{iview}.ProjObjectAngle,ProjObjectAngle))
+                    ProjObjectCoord=[];%dt not the same for all fields
+                end
+            end
+            if ~isempty(ProjObjectCoord)
+                MergeData.ListGlobalAttribute=[MergeData.ListGlobalAttribute {'ProjObjectCoord'} {'ProjObjectAngle'}];
+                MergeData.ProjObjectCoord=ProjObjectCoord;
+                MergeData.ProjObjectAngle=ProjObjectAngle;
+            end
+        end
+        % coord unit
+        if isfield(Data{1},'CoordUnit')
+            CoordUnit=Data{1}.CoordUnit;
+            for iview =2:numel(Data)
+                if ~(isfield(Data{iview},'CoordUnit')&& isequal(Data{iview}.CoordUnit,CoordUnit))
+                    CoordUnit=[];%CoordUnit not the same for all fields
+                end
+            end
+            if ~isempty(CoordUnit)
+                MergeData.ListGlobalAttribute=[MergeData.ListGlobalAttribute {'CoordUnit'}];
+                MergeData.CoordUnit=CoordUnit;
+            end
+        end
+        % time unit
+        if isfield(Data{1},'TimeUnit')
+            TimeUnit=Data{1}.TimeUnit;
+            for iview =2:numel(Data)
+                if ~(isfield(Data{iview},'TimeUnit')&& isequal(Data{iview}.TimeUnit,TimeUnit))
+                    TimeUnit=[];%TimeUnit not the same for all fields
+                end
+            end
+            if ~isempty(TimeUnit)
+                MergeData.ListGlobalAttribute=[MergeData.ListGlobalAttribute {'TimeUnit'}];
+                MergeData.TimeUnit=TimeUnit;
+            end
+        end
+        error=struct2nc(OutputFile,MergeData);%save result file
+        if isempty(error)
+            disp(['output file ' OutputFile ' written'])
+        else
+            disp(error)
+        end
+    end
+end
+ellapsed_time=toc(tstart);
+disp(['total ellapsed time ' num2str(ellapsed_time/60,2) ' minutes'])
+disp([ num2str(ellapsed_time/(60*NbField),3) ' minutes per iteration'])
+
+%'merge_field': concatene fields
+%------------------------------------------------------------------------
+function [MergeData,errormsg]=merge_field(Data)
+%% default output
+if isempty(Data)||~iscell(Data)
+    MergeData=[];
+    return
+end
+errormsg='';
+MergeData=Data{1};% merged field= first field by default, reproduces the global attributes of the first field
+NbView=length(Data);
+if NbView==1% if there is only one field, just reproduce it in MergeData
+    return 
+end
+
+%% group the variables (fields of 'Data') in cells of variables with the same dimensions
+[CellInfo,NbDim,errormsg]=find_field_cells(Data{1});
+if ~isempty(errormsg)
+    return
+end
+
+%LOOP ON GROUPS OF VARIABLES SHARING THE SAME DIMENSIONS
+for icell=1:length(CellInfo)
+    if NbDim(icell)~=1 % skip field cells which are of dim 1
+        switch CellInfo{icell}.CoordType
+            case 'scattered'  %case of input fields with unstructured coordinates: just concatene data
+                for ivar=CellInfo{icell}.VarIndex %  indices of the selected variables in the list FieldData.ListVarName
+                    VarName=Data{1}.ListVarName{ivar};
+                    for iview=2:NbView
+                        MergeData.(VarName)=[MergeData.(VarName); Data{iview}.(VarName)];
+                    end
+                end
+            case 'grid'        %case of fields defined on a structured  grid
+                FFName='';
+                if isfield(CellInfo{icell},'VarIndex_errorflag') && ~isempty(CellInfo{icell}.VarIndex_errorflag)
+                    FFName=Data{1}.ListVarName{CellInfo{icell}.VarIndex_errorflag};% name of errorflag variable
+                    MergeData.ListVarName(CellInfo{icell}.VarIndex_errorflag)=[];%remove error flag variable in MergeData (will use NaN instead)
+                    MergeData.VarDimName(CellInfo{icell}.VarIndex_errorflag)=[];
+                    MergeData.VarAttribute(CellInfo{icell}.VarIndex_errorflag)=[];
+                end
+                % select good data on each view
+                for ivar=CellInfo{icell}.VarIndex  %  indices of the selected variables in the list FieldData.ListVarName
+                    VarName=Data{1}.ListVarName{ivar};
+                    for iview=1:NbView
+                        if isempty(FFName)
+                            check_bad=isnan(Data{iview}.(VarName));%=0 for NaN data values, 1 else
+                        else
+                            check_bad=isnan(Data{iview}.(VarName)) | Data{iview}.(FFName)~=0;%=0 for NaN or error flagged data values, 1 else
+                        end
+                        Data{iview}.(VarName)(check_bad)=0; %set to zero NaN or data marked by error flag
+                        if iview==1
+                            %MergeData.(VarName)=Data{1}.(VarName);% initiate MergeData with the first field
+                            MergeData.(VarName)(check_bad)=0; %set to zero NaN or data marked by error flag
+                            NbAver=~check_bad;% initiate NbAver: the nbre of good data for each point
+                        elseif size(Data{iview}.(VarName))~=size(MergeData.(VarName))
+                            errormsg='sizes of the input matrices do not agree, need to interpolate on a common grid using a projection object';
+                            return
+                        else                             
+                            MergeData.(VarName)=MergeData.(VarName) +double(Data{iview}.(VarName));%add data
+                            NbAver=NbAver + ~check_bad;% add 1 for good data, 0 else
+                        end
+                    end
+                    MergeData.(VarName)(NbAver~=0)=MergeData.(VarName)(NbAver~=0)./NbAver(NbAver~=0);% take average of defined data at each point
+                    MergeData.(VarName)(NbAver==0)=NaN;% set to NaN the points with no good data
+                end
+        end
+%         if isempty(FFName)
+%             FFName='FF';
+%         end
+%         MergeData.(FFName)(NbAver~=0)=0;% flag to 1 undefined summed data
+%         MergeData.(FFName)(NbAver==0)=1;% flag to 1 undefined summed data
+    end
+end
+
+
+    
