Hi Victor

(next_year_obs (1) - this_year_obs (365) + 365) would do the trick in this obvious case but

I would suggest to work always with complete dates which means that you include the year in your calculation (consider the case of leap years).

Convert your observation in the form of  year + DOY into a regular date and use some function of your favourite programming language. Attached a quick example with PHP

Regards Markus

Hi Markus

I am glad to hearing from you. I am not too sure if I got your point...Basically I do not undersand the "(1)" and "(365)".

Did you mean this:

(DOYn+1 – DOYn) + 365

Thanks

Victor

Hola Victor

You might try the following formula that accounts for the circularity of the calendar before substracting dates (modified from Regniere and Bolstad 1994):

y = 1/2 [1 - cos(2 PI (Day - 31) / 365)]

Hope this helps.

Un saludo!

Juan P.

Hola Juan Pedro,

Gracias!, We thought in similar approaches, but the problem is that it is needed an extra variable to define the quadrant... This is why we were thinking in other approaches that use a relative reference to recalculate the dates. 

Un abrazo

Víctor