Reading and visualizing netcdf with vectors of differing lengths

This is my first time reading netcdf data. I can read the file and variables of interest as follows:

vardata=ncread('TL__Map1_15C_sand1__20mres_-36.265137N_174.790466','TLdata');

H_latdata=ncread('TL__Map1_15C_sand1__20mres_-36.265137N_174.790466','H_latdata');
H_londata=ncread('TL__Map1_15C_sand1__20mres_-36.265137N_174.790466','H_londata');
H_freqdata=ncread('TL__Map1_15C_sand1__20mres_-36.265137N_174.790466','H_freqdata');

Unfortunately I cannot attach the file because even in Zip format it is greater than 5mb.

>> whos vardata
  Name          Size                    Bytes  Class     Attributes

  vardata      91x489x280            49838880  single      
  

I'd like to be able to plot/visualize the data, but when I try to use plot3() it tells me the vectors must be the same length. Is there another way?

My goal is to find the freq value for a specific lat/lon, but in order to do make a selection of positions of interest, I need to look at the positions I have and see how they vary.

Answer 1

[KSSV]

If you want to attach the file, you can upload in some cloud spaces (google drive) and share the link here without asking the login's credentials.

[p,m,n] = size(vardata) ; 
for i = 1:p
     pcolor(H_londata,H_latdata,squeeze(vardata(i,:,:))') ;
    shading interp
    drawnow
end

If you want to extract a series from the (i,j) position

i = 3 ;
j = 4 ; 
v = squeeze(vardata(:,j,i)) ; 
plot(v)

[Louise Wilson]

Thank you! I have the data here: https://drive.google.com/file/d/1PTJlARg5sb4ktJkNpngKi2A75gtHaYJb/view?usp=sharing

When I try the first chunk of code, I get an error that the matrix dimensions must agree.

[KSSV]

Check your data.....edited the code......Try running like shown.

[Louise Wilson]

That also does not work :(

>> [m,n,p] = size(vardata) ; 
for i = 1:p
    pcolor(H_londata,H_latdata,vardata(:,:,i)') ;
    shading interp
    drawnow
end
Error using pcolor (line 61)
Matrix dimensions must agree.

[Louise Wilson]

You will see in the data that some of the values are NaN, could that be an issue? They could be replaced with zeroes.

I tried this, but no joy...

vardata(isnan(vardata))=0;

[m,n,p] = size(vardata) ; 
for i = 1:p
    pcolor(H_londata,H_latdata,vardata(i,:,:)') ;
    shading interp
    drawnow
end
Error using  ' 
Transpose on ND array is not defined. Use PERMUTE instead.

[KSSV]

No NaN is not the issue, the dimensions are issue. Edited the code. Hope you have noticed it.

[Louise Wilson]

Ooh it looks awesome, thank you so much!

Is the second part for extracting specific data from a lat/lon still okay?

I'd like to input a specific lat (n) /lon (m) and get the p value.

j=6.291 %lon
i=-3.257 %lat
v = squeeze(vardata(:,j,i)) ; 

Index in position 2 is invalid. Array indices must be positive
integers or logical values.

[KSSV]

i, j should be indices, not lon/ lat values.

Also note that H_londata,H_latdata are not in degrees. If you have fixed i, j as values instead of the indices, Use:

idx = knnsearch([X(:) Y(:)],[i j]) ; 
[r,c] = ind2sub(size(X),idx) ;
v = squeeze(vardata(:,r,c)) ; 

And thanks is accepting/ voting the answer. :)

[Louise Wilson]

Done :) Thank you!

They are in UTM so a coordinate format just different to decimal degrees. I will try your suggestion, thank you.