[202] | 1 | ;+ |
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[232] | 2 | ; |
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[202] | 3 | ; @file_comments |
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[238] | 4 | ; similar to <pro>extrapolate</pro> but could to the job in a better way |
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| 5 | ; because the ; extrapolated values are smoothed... |
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| 6 | ; takes more time than <pro>extrapolate</pro>. |
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| 7 | ; extrapolate data where mskin is equal 0 by filling |
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[202] | 8 | ; step by step the coastline points with the mean value of the 8 neighbourgs. |
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| 9 | ; |
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| 10 | ; @categories |
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| 11 | ; Interpolation |
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| 12 | ; |
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| 13 | ; @param in {in}{required}{type=2d array} |
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| 14 | ; data to be extrapolate |
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| 15 | ; |
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[232] | 16 | ; @param mskin {in}{required}{type=2d array or -1} |
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[202] | 17 | ; a 2D array, the land-sea mask of the output data (1 on ocean, 0 on land) |
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| 18 | ; put -1 if input data are not masked |
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| 19 | ; |
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| 20 | ; @keyword MINVAL {type=scalar}{default=not used} |
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| 21 | ; to specify a minimum value to the extrapolated values |
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| 22 | ; |
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| 23 | ; @keyword MAXVAL {type=scalar}{default=not used} |
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| 24 | ; to specify a maximum value to the extrapolated values |
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| 25 | ; |
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| 26 | ; @keyword GE0 {type=scalar 0 or 1}{default=0} |
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| 27 | ; put 1 to force the extrapolated values to be larger than 0, same as using minval=0. |
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| 28 | ; |
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| 29 | ; @returns |
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| 30 | ; the extrapolated array with no more masked values |
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| 31 | ; |
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| 32 | ; @restrictions |
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| 33 | ; You cannot specify the number of iterations done in the extrapolation process |
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| 34 | ; |
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| 35 | ; @examples |
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| 36 | ; IDL> a=extrapsmooth(dist(jpi,jpj),tmask[*,*,0],/x_periodic) |
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| 37 | ; IDL> tvplus, a |
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| 38 | ; compare to extrapolate result: |
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| 39 | ; IDL> b=extrapolate(dist(jpi,jpj),tmask[*,*,0],/x_periodic) |
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| 40 | ; IDL> tvplus, b, window = 1 |
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| 41 | ; |
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| 42 | ; @history |
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| 43 | ; January 2007: Sebastien Masson (smasson\@lodyc.jussieu.fr) |
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| 44 | ; |
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| 45 | ; @version |
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| 46 | ; $Id$ |
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| 47 | ;- |
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[231] | 48 | ; |
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[202] | 49 | FUNCTION extrapsmooth, in, mskin, x_periodic = x_periodic, MINVAL = minval, MAXVAL = maxval, GE0 = ge0 |
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| 50 | ; |
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[226] | 51 | compile_opt strictarr, strictarrsubs |
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| 52 | ; |
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| 53 | sz = size(reform(in)) |
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| 54 | IF sz[0] NE 2 THEN BEGIN |
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[236] | 55 | ras = report('Input arrays must have 2 dimensions') |
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[202] | 56 | return, -1 |
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| 57 | ENDIF |
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| 58 | nx = sz[1] |
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| 59 | ny = sz[2] |
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| 60 | IF n_elements(mskin) EQ 1 AND mskin[0] EQ -1 THEN mskin = replicate(1b, nx, ny) |
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[226] | 61 | IF n_elements(mskin) NE nx*ny THEN BEGIN |
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[236] | 62 | ras = report('input grid mask do not have the good size') |
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[202] | 63 | return, -1 |
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| 64 | ENDIF |
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| 65 | ; |
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| 66 | out = reform(in) |
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| 67 | whmsk = where(mskin EQ 0, nbr) |
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| 68 | IF nbr NE 0 THEN out[temporary(whmsk)] = !values.f_nan |
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[226] | 69 | ; add values on each side of the array to avoid boundary effects |
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[202] | 70 | nx2 = nx/2 |
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| 71 | ny2 = ny/2 |
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| 72 | add = replicate(!values.f_nan, nx, ny2) |
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| 73 | out = [[add], [temporary(out)], [add]] |
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| 74 | IF keyword_set(x_periodic) THEN BEGIN |
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| 75 | add1 = out[0:nx2, *] |
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| 76 | add2 = out[nx-nx2:nx-1, *] |
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| 77 | out = [add2, [temporary(out)], add1] |
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[226] | 78 | ENDIF ELSE BEGIN |
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[202] | 79 | add = replicate(!values.f_nan, nx2, ny+2*ny2) |
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| 80 | out = [add, [temporary(out)], add] |
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| 81 | ENDELSE |
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| 82 | ; |
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| 83 | msk0 = where(finite(out) EQ 0) |
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| 84 | nnan = total(finite(out, /nan)) |
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| 85 | i = 1 |
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| 86 | WHILE nnan NE 0 DO BEGIN |
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| 87 | tmp = smooth(out, 2*i + 1, /nan) |
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| 88 | ; find only the changed values that where on land |
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| 89 | new = where(finite(out) EQ 0 AND finite(tmp) EQ 1, nnew) |
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| 90 | IF nnew EQ 0 then nnan = 0 ELSE BEGIN |
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| 91 | IF keyword_set(ge0) THEN tmp = 0. > temporary(tmp) |
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| 92 | IF n_elements(minval) NE 0 THEN tmp = minval > temporary(tmp) |
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| 93 | IF n_elements(maxval) NE 0 THEN tmp = temporary(tmp) < maxval |
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| 94 | out[new] = tmp[new] |
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| 95 | i = i+1 |
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| 96 | nnan = total(finite(out, /nan)) |
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| 97 | ENDELSE |
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| 98 | ENDWHILE |
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| 99 | ; a final smooth is needed |
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| 100 | out = smooth(temporary(out), 5, /nan) |
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| 101 | IF keyword_set(ge0) THEN out = 0. > temporary(out) |
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| 102 | IF n_elements(minval) NE 0 THEN out = minval > temporary(out) |
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| 103 | IF n_elements(maxval) NE 0 THEN out = temporary(out) < maxval |
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| 104 | ; get back to the original domain |
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| 105 | out = (temporary(out))[nx2:nx+nx2-1, ny2:ny+ny2-1] |
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| 106 | ; put back the non-maskqed values |
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| 107 | whmsk = where(mskin NE 0) |
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| 108 | out[whmsk] = in[whmsk] |
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| 109 | ; |
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| 110 | return, out |
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| 111 | END |
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