how to bin data

i have (attahed) dataset of 3 cols : (1st for lat. ,2nd for long., and the 3rd for datavalues).

i need to bin these data in a grid of lat(2.5) x long(5) degrees.

then plot the results with surf function over the coressponding map location ?

[ahmad Saad]

i prefer to use 'for' loop instead ???

[Dyuman Joshi]

@ahmad Saad Why? For what reason?

Matt has provided an efficient and a fully working solution. Why not use it?

[ahmad Saad]

@Dyuman Joshi it seems that the two figures are not similar.

i think "for" loop is straight forward

[Matt J]

it seems that the two figures are not similar.

Which two figures? The figures in my 2 answers are different because they use different regridding algorithms. Both of them can be implemented using a for-loop, but how would that help you decide between them? It won't change the surfaces.

[ahmad Saad]

@Matt J deep thanks for your explaination

Answer 1

[Matt J]

[lat,lon,vals]=readvars('dataset.txt');
LAT=min(lat):2.5:max(lat);
LON=min(lon):5:max(lon);

VALS=griddata(lat,lon,vals, LAT',LON);

Warning: Duplicate data points have been detected and removed - corresponding values have been averaged.

surf(LAT,LON,VALS)

Answer 2

[Matt J]

Or perhaps,

[lat,lon,vals]=readvars('dataset.txt');
LAT=min(lat):2.5:max(lat);
LON=min(lon):5:max(lon);

G=findgroups(discretize(lat,LAT), discretize(lon,LON));

VALS=splitapply(@sum,vals,G)./splitapply(@numel,vals,G);
VALS=reshape(VALS, numel(LAT)-1,[]);


LAT=conv(LAT,[1,1]/2,'valid');
LON=conv(LON,[1,1]/2,'valid');
surf(LAT,LON,VALS);