how to solve Error using .' Transpose on ND array is not defined. Use PERMUTE instead. Error in interp2 (line 122) V = V.';?

Hello I want to regrid my netcdf file based on lat and lon from 0.5 to 1 degree. now I faced this error.

Can anyone help me? here is my code:

filename='precip.mon.total.v2018.nc';
ncdisp(filename)       
lat = ncread(filename,'lat');     
lon = ncread(filename,'lon');  
precip = ncread(filename,'precip');
t = ncdateread(filename,'time');

ds = 0.25 ;
loni = min(lon):ds:max(lon) ;
lati = min(lat):ds:max(lat) ;

[Loni,Lati] = meshgrid(loni,lati) ;



size(lat)
size(lon)
size(precip)

newpreceip=interp2(lat, lon, precip, loni, lati)

and that is wath appears in my comand window:

Source:
           C:\Users\Behzad\Desktop\precip.mon.total.v2018.nc
Format:
           netcdf4_classic
Global Attributes:
           Original_Source = 'http://www.dwd.de/en/FundE/Klima/KLIS/int/GPCC/GPCC.htm
                              is the webpage and the data is at ftp://ftp.dwd.de/pub/data/gpcc/download.html'
           Reference       = 'Users of the data sets are kindly requested to give feed back and to refer to GPCC publications on this webpage: http://www.dwd.de/bvbw/appmanager/bvbw/dwdwwwDesktop/?_nfpb=true&_pageLabel=_dwdwww_klima_umwelt_datenzentren_wzn&T12404518261141645246564gsbDocumentPath=Content%2FOeffentlichkeit%2FKU%2FKU4%2FKU42%2Fteaser__product__access.html&_state=maximized&_windowLabel=T12404518261141645246564&lastPageLabel=_dwdwww_klima_umwelt_datenzentren_wzn'
           original_source = 'ftp://ftp-anon.dwd.de/pub/data/gpcc/html/fulldata_download.html'
           Conventions     = 'CF 1.0'
           dataset_title   = 'Global Precipitation Climatology Centre (GPCC)'
           References      = 'https://www.esrl.noaa.gov/psd/data/gridded/data.gpcc.html'
           title           = 'GPCC Full Data Reanalysis Version 2018 0.5x0.5 Monthly Total'
           history         = 'Created 09/2018  based on V2018 data obtained via ftp'
           data_modified   = '2019-03-12'
           _NCProperties   = 'version=2,netcdf=4.6.3,hdf5=1.10.5'
Dimensions:
           lat   = 360
           lon   = 720
           nbnds = 2
           time  = 1512  (UNLIMITED)
Variables:
    lat   
           Size:       360x1
           Dimensions: lat
           Datatype:   single
           Attributes:
                       long_name          = 'Latitude'
                       units              = 'degrees_north'
                       standard_name      = 'latitude'
                       axis               = 'Y'
                       coordinate_defines = 'point'
                       actual_range       = [89.75       -89.75]
    lon   
           Size:       720x1
           Dimensions: lon
           Datatype:   single
           Attributes:
                       long_name          = 'Longitude'
                       units              = 'degrees_east'
                       standard_name      = 'longitude'
                       actual_range       = [0.25        359.75]
                       axis               = 'X'
                       coordinate_defines = 'point'
    time  
           Size:       1512x1
           Dimensions: time
           Datatype:   double
           Attributes:
                       long_name          = 'Time'
                       units              = 'days since 1800-1-1 00:00:00'
                       delta_t            = '0000-01-00 00:00:00'
                       avg_period         = '0000-01-00 00:00:00'
                       standard_name      = 'time'
                       axis               = 'T'
                       coordinate_defines = 'start'
                       actual_range       = [33237  79227]
    precip
           Size:       720x360x1512
           Dimensions: lon,lat,time
           Datatype:   single
           Attributes:
                       missing_value = -9.969209968386869e+36
                       units         = 'mm'
                       var_desc      = 'Precipitation'
                       level_desc    = 'Surface'
                       parent_stat   = 'Observations'
                       long_name     = 'GPCC Monthly total of precipitation'
                       valid_range   = [0  8000]
                       statistic     = 'Total'
                       level         = 'Surface'
                       actual_range  = [0      4552.4302]
                       dataset       = 'GPCC Precipitation 0.5degree V2018 Full Reanalysis'
ans =
   360     1
ans =
   720     1
ans =
         720         360        1512
Error using  .' 
Transpose on ND array is not defined. Use PERMUTE instead.
Error in interp2 (line 122)
        V = V.';
Error in test100 (line 25)
newpreceip=interp2(lat, lon, precip, loni, lati) 

Answer 1

[Matt J]

Because precip is not a 2D array, interp2 is the wrong tool. One alternative:

F=griddedInterpolant({lat,lon,t},precip);

newpreceip=F({lati,loni,t});

[BN]

Dear Matt J

Thank you for your answer. I use your suggestion but this error is appear:

Error using griddedInterpolant

Grid coordinates must be of the same type, single or double.

Error in test100 (line 40)

F=griddedInterpolant({lat,lon,t},precip);

Do you have any idea?

best regards

[Matt J]

You should convert all your variables to double floats.

[BN]

Dear Matt J

Thank you again for your nice cooperation. after I convert all variable to double this error was apear:

Error using griddedInterpolant

The grid vectors are not strictly monotonic increasing.

Error in test100 (line 50)

F=griddedInterpolant({lat,lon,t},precip);

How to fix this error?

clc
clear
format compact
close all

filename='precip.mon.total.v2018.nc';
ncdisp(filename)       
lat = ncread(filename,'lat');     
lon = ncread(filename,'lon');  
precip = ncread(filename,'precip');
t = ncread(filename,'time');

lat=double(lat);
lon=double(lon);
precip=double(precip);
t=double(t);
index=find(precip==-9.969209968386869e+36);
precip(index)=nan;

ds = 0.25 ;
loni = min(lon):ds:max(lon) ;
lati = min(lat):ds:max(lat) ;

[Loni,Lati] = meshgrid(loni,lati) ;


[latgrid,longrid] = meshgrid(lat,lon);

size(lat)
size(lon)
size(precip)
%regrid data
F=griddedInterpolant({lat,lon,t},precip);
newpreceip=F({lati,loni,t});

[Walter Roberson]

'precip.mon.total.v2018.nc' does not appear to be attached for us to test with.

I notice that for lat,

actual_range = [89.75 -89.75]

Are the values in lat strictly decreasing through that range?

[BN]

Dear Walter Roberson

thank you for your answer. yes lat values are decerasing. first is 89.75 and -89.75 is end, and 360 lat are in between this range. infact lat is 360*1 double. you can download netcdf file at this link below:

ftp://ftp.cdc.noaa.gov/Datasets/gpcc/full_v2018/precip.mon.total.v2018.nc

morever I attached lat variable in .m format for you to see it.

thank you again and waiting for you to answer.

best regards

[Matt J]

But the error message has told you that they must be increasing. So, make the obvious adjustments:

F=griddedInterpolant({flip(lat),lon,t},flip(precip,1));
newpreceip=F({lati,loni,t});

[BN]

Dear Matt J

Thank you again for your answer. after using this code I faced the error below:

Error using griddedInterpolant

The grid vectors do not define a grid of points that match the

given values.

Error in test100 (line 52)

F=griddedInterpolant({flip(lat),lon,t},flip(precip,1));

do you have any idea?

best regards

[Matt J]

Yous should show us the output of

>> whos lat lon t precip

[BN]

Dear Matt J

The output is:

>> whos lat lon t precip
  Name           Size                       Bytes  Class     Attributes

  lat          360x1                         2880  double              
  lon          720x1                         5760  double              
  precip       720x360x1512            3135283200  double              
  t           1512x1                        12096  double              

the screenshot of workplace is also attached. thank you

[Matt J]

This should solve it:

 F=griddedInterpolant({lon,flip(lat),t},flip(precip,1));
 
 newpreceip=F({loni,lati,t});

[BN]

Dear Matt J

Thank you for your precious help.

This solved my problem.

Best Regards

Answer 2

[Soumik Ghosh]

I followed your answer on mathwork but cannot solve my issue with data. Could you help me to fix the error? I have used the following code:

File='rf.1998.2010.nc'
rf=double(ncread(File, 'rf'));
time=double(ncread(File, 'time'));
lon=double(ncread(File, 'lon'));
rain=rf'
rain(isinf(rain)|isnan(rain))=0;
F=griddedInterpolant({lon,flip(lat),time},flip(rain,1));

The following error is showing:

Error using griddedInterpolant

The grid vectors must be strictly monotonically increasing.

==============

Name Size Bytes Class Attributes

lat 252x1 2016 double

lon 317x1 2536 double

rain 317x252x4748 3034313856 double

time 4748x1 37984 double

===============

Best Regards,

Soumik

[BN]

Dear @Soumik Ghosh

I found that this error appears because of ascending order or descending order in lon or lat data. Check lat and lon and make sure both of them are ascending or descending.

Note that if lat is ascending and lon is descending you can use this:

ds = 1
lat = max(lat):-ds:min(lat); %if lat be in descending order

Good Luck

Behzad Navidi

[Rik]

Since this isn't an answer, the content should be merged with the separately posted question and then deleted.

[Soumik Ghosh]

Hi Behzad,

Thanks for your reply. I have corrected and posted in the following link.See you there.

https://www.mathworks.com/matlabcentral/answers/502474-error-using-during-transpose-3d-variable-from-nc-file-error-transpose-on-nd-array-is-not-def?s_tid=mlc_ans_email_view#add_answer

With Regards,

Soumik