How to average Bimonthly into monthly and yearly?

Hi Everyone,

Please, I have Bimonthly images for 37 years. (1982-2018). I need your help to create a code to average Bimonthly data into monthly and yearly. Please, look at the following data:

'1982_01_15a.n07-VI3g.tif'

'1982_01_15b.n07-VI3g.tif'

'1982_02_15a.n07-VI3g.tif'

'1982_02_15b.n07-VI3g.tif'

'1982_03_15a.n07-VI3g.tif'

'1982_03_15b.n07-VI3g.tif'

'1982_04_15a.n07-VI3g.tif'

'1982_04_15b.n07-VI3g.tif'

'1982_05_15a.n07-VI3g.tif'

'1982_05_15b.n07-VI3g.tif'

'1982_06_15a.n07-VI3g.tif'

'1982_06_15b.n07-VI3g.tif'

'1982_07_15a.n07-VI3g.tif'

'1982_07_15b.n07-VI3g.tif'

'1982_08_15a.n07-VI3g.tif'

'1982_08_15b.n07-VI3g.tif'

'1982_09_15a.n07-VI3g.tif'

'1982_09_15b.n07-VI3g.tif'

'1982_10_15a.n07-VI3g.tif'

'1982_10_15b.n07-VI3g.tif'

'1982_11_15a.n07-VI3g.tif'

'1982_11_15b.n07-VI3g.tif'

'1982_12_15a.n07-VI3g.tif'

'1982_12_15b.n07-VI3g.tif'

.

.

.

.

'2018_12_15a.n07-VI3g.tif'

'2018_12_15b.n07-VI3g.tif'

Thank you in advance

Reyadh

Answer 1

[Bjorn Gustavsson]

Tips: have a look at the dir, for function and keyword repsectively. Presumably you have some function for reading your .tif-files, but those two constructs should get you going.

HTH

[Reyadh Albarakat]

Thank you for your answer,

In fact, I create a simple code to read the tiff images. however, my wondering is how to create acode to averge bimonthly to monthly and yearly. The following code is just to read the data:

cd E:\NDVI_Reyadh\ndvi_1982_2018
F_read_avhrr=dir('*.tif');
for i=1:length(F_read_avhrr)
        FileNames_avhrr{i}= F_read_avhrr(i).name;
        ndvi{i} = imread(FileNames_avhrr{i});
        ndvi{i} = (double(ndvi{i}));
end
clear i
clear ans i

[Bjorn Gustavsson]

Well the way I understand your data, and code it would be something like this to go from bimonthly to monthly:

for i1 = 2:2:numel(ndvi)
  Monthly_dvi{i1/2} = ndvi{i1-1}/2 + ndvi{i1}/2;
end

For yearly average you might want to be a bit more cunning coding it...

HTH

[Reyadh Albarakat]

Thank you Bjorn for your reply. Please, do a favor to create a yealy average. Please complete your help. I am a beginner user in Matlab

Thank you

Reyadh

[Bjorn Gustavsson]

I could, but in the long run it is better if you do it yourself. Take the task step-by-step. You know that you can have nested loops, and that you can use index-variables that you can increment anywhere you want, you know how many months there is in a year. You can do this!