[110] | 1 | ;+ |
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| 2 | ; |
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[136] | 3 | ; @file_comments |
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[125] | 4 | ; interpolate data from an irregular 2D grid to any 2D grid. |
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| 5 | ; Only 1 method available = bilinear |
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| 6 | ; |
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[231] | 7 | ; @categories |
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[157] | 8 | ; Interpolation |
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[110] | 9 | ; |
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[163] | 10 | ; @param method {in}{required}{type=string} |
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[238] | 11 | ; the interpolation method. must be 'bilinear' |
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[110] | 12 | ; |
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[163] | 13 | ; @param datain {in}{required}{type=2d array} |
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[238] | 14 | ; the input data to interpolate |
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[136] | 15 | ; |
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[205] | 16 | ; @param lonin {in}{required}{type=2d array} |
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[238] | 17 | ; the longitude of the input data |
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[136] | 18 | ; |
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[205] | 19 | ; @param latin {in}{required}{type=2d array} |
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[238] | 20 | ; the latitude of the input data. |
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[136] | 21 | ; |
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[205] | 22 | ; @param mskin {in}{required}{type=2d array or -1} |
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[136] | 23 | ; a 2D array, the land-sea mask of the input data (1 on ocean, 0 on land) |
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[202] | 24 | ; put -1 if input data are not masked |
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[136] | 25 | ; |
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[205] | 26 | ; @param lonout {in}{required}{type=1d or 2d array} |
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[238] | 27 | ; the longitude of the output data. |
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[136] | 28 | ; |
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[205] | 29 | ; @param latout {in}{required}{type=1d or 2d array} |
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[238] | 30 | ; the latitude of the output data. |
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[136] | 31 | ; |
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[202] | 32 | ; @param mskout {in}{required}{type=2d array or -1} |
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[163] | 33 | ; a 2D array, the land-sea mask of the output data (1 on ocean, 0 on land) |
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[202] | 34 | ; put -1 if output data are not masked |
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[136] | 35 | ; |
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[163] | 36 | ; @keyword WEIG {type=2d array} |
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| 37 | ; (see ADDR) |
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| 38 | ; |
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| 39 | ; @keyword ADDR {type=2d array} |
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[231] | 40 | ; 1) at the first call of fromirr: |
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[228] | 41 | ; This keyword can be set to a named variable (undefined or equal to 0) into which the |
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| 42 | ; addresses used to perform the interpolation will be copied when the current routine exits. |
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| 43 | ; 2) Next, once this keyword is set to a defined 2d array, it is used to bypass the computation |
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| 44 | ; of the weights and addresses used to perform the interpolation. In this case, fromirr simply |
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| 45 | ; compute the interpolated field as: |
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[110] | 46 | ; dataout = total(weig*datain[addr], 1) |
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| 47 | ; dataout = reform(dataout, jpio, jpjo, /over) |
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[228] | 48 | ; In that case, method, lonin, latin, are not used (but are necessary). |
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| 49 | ; lonout, latout are used only to know the output domain size |
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[110] | 50 | ; |
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[271] | 51 | ; @keyword |
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| 52 | ; _EXTRA to be able to call fromirr with _extra keyword |
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| 53 | ; |
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[136] | 54 | ; @returns |
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| 55 | ; 2D array the interpolated data |
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[110] | 56 | ; |
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[125] | 57 | ; @restrictions |
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| 58 | ; We supposed the data are located on a sphere, with a periodicity along |
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| 59 | ; the longitude. |
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| 60 | ; Note that the input data can contain the same cells several times |
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| 61 | ; (like ORCA grid near the north pole boundary) |
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[110] | 62 | ; |
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| 63 | ; @examples |
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[125] | 64 | ; |
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[228] | 65 | ; To interpolate 1 field: |
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| 66 | ; |
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[118] | 67 | ; IDL> tncep = fromirr('bilinear', topa, glamt, gphit, tmask[*,*,0], lonout, latout, mskout) |
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[110] | 68 | ; |
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[228] | 69 | ; or if you have several fields to interpolate from the same source and target grids |
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[110] | 70 | ; |
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[228] | 71 | ; 1) get back the weights and addresses in variables a and b |
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| 72 | ; (that must be undefined or equal to 0 before calling fromirr) |
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| 73 | ; |
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[118] | 74 | ; IDL> t1ncep = fromirr('bilinear', topa, glamt, gphit, tmask[*,*,0], lonout, latout, mskout $ |
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[110] | 75 | ; , WEIG = a, ADDR = b) |
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[118] | 76 | ; IDL> help, a, b |
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[228] | 77 | ; |
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[238] | 78 | ; 2) use a and b that are now defined to bypass the computation of the weights |
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| 79 | ; and addresses and speed-up the computation! |
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[228] | 80 | ; |
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[118] | 81 | ; IDL> t2ncep = fromirr('bilinear', topa, WEIG = a, ADDR = b) |
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[110] | 82 | ; |
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| 83 | ; @history |
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[125] | 84 | ; June 2006: Sebastien Masson (smasson\@lodyc.jussieu.fr) |
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| 85 | ; |
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[231] | 86 | ; @version |
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| 87 | ; $Id$ |
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[118] | 88 | ; |
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[110] | 89 | ;- |
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| 90 | ; |
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| 91 | FUNCTION fromirr, method, datain, lonin, latin, mskin, lonout, latout, mskout $ |
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[271] | 92 | , WEIG = weig, ADDR = addr, _EXTRA = ex |
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[110] | 93 | ; |
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[125] | 94 | compile_opt strictarr, strictarrsubs |
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[110] | 95 | ; |
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| 96 | ;--------------- |
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| 97 | ; atmospheric grid parameters |
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| 98 | ;--------------- |
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| 99 | alon = lonin |
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| 100 | alat = latin |
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| 101 | get_gridparams, alon, alat, jpia, jpja, 2, /double |
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| 102 | ;--------------- |
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| 103 | ; Oceanic grid parameters |
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| 104 | ;--------------- |
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| 105 | olon = lonout |
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| 106 | olat = latout |
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| 107 | get_gridparams, olon, olat, jpio, jpjo, 2, /double |
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| 108 | ;--------------- |
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| 109 | ; Compute weight and address |
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| 110 | ;--------------- |
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[113] | 111 | IF NOT (keyword_set(weig) AND keyword_set(addr)) THEN BEGIN |
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[110] | 112 | CASE method OF |
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| 113 | 'bilinear':compute_fromirr_bilinear_weigaddr, alon, alat, mskin, olon, olat, mskout, weig, addr |
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[125] | 114 | ELSE:BEGIN |
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[236] | 115 | ras = report(' unknown interpolation method... we stop') |
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[110] | 116 | stop |
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| 117 | ENDELSE |
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| 118 | ENDCASE |
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| 119 | ENDIF |
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| 120 | ;--------------- |
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| 121 | ; to the interpolation |
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| 122 | ;--------------- |
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| 123 | dataout = total(weig*datain[addr], 1) |
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| 124 | dataout = reform(dataout, jpio, jpjo, /over) |
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| 125 | ; |
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| 126 | RETURN, dataout |
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| 127 | END |
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