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Re: [ferret_users] Robinson map projection



Hi Patrick,

> Following http://www.pmel.noaa.gov/maillists/tmap/ferret_users/fu_2011/msg00129.html
> I am wondering if anyone has succeeded to code a Robinson projection
> with ferret ?
> It is not so easy because this projection is achieved through the
> use of tabular coordinates rather than mathematical formulae.

But I guess there must be interpolation formulae between the discrete,
tabulated latitudes.

I've never tried map projection, but it seems to me that you can
express the table in the following manner.  In a pseudo-Ferret code, 

  let x_page = if y > y1 then xp1 else \
    formula_for_x_page_less_than_y1

  let xp1 = if y > y2 then xp2 else \
    formula_for_x_page_between_y1_and_y2

  let xp2 = if y > y3 then xp3 else \
    formula_for_x_page_between_y2_and_y3

  . . . and so on . . .

It's tedious but looks doable.

Ryo


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