1 | ;+ |
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2 | ; |
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3 | ; @file_comments |
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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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7 | ; @categories interpolation |
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8 | ; |
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9 | ; @param method {in}{required} a string defining the interpolation method. must be 'bilinear' |
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10 | ; @param datain {in}{required} a 2D array the input data to interpolate |
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11 | ; @param lonin {in}{optional} a 2D array defining the longitude of the input data |
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12 | ; @param latin {in}{optional} a 2D array defining the latitude of the input data. |
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13 | ; @param mskin {in}{optional} a 2D array, the land-sea mask of the input data (1 on ocean, 0 on land) |
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14 | ; @param lonout {in}{optional} 1D or 2D array defining the longitude of the output data. |
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15 | ; @param latout {in}{optional} 1D or 2D array defining the latitude of the output data. |
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16 | ; @param mskout {in}{required} a 2D array, the land-sea mask of the ouput data (1 on ocean, 0 on land) |
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17 | ; |
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18 | ; @keyword WEIG (see ADDR) |
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19 | ; @keyword ADDR 2D arrays, weig and addr are the weight and addresses used to |
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20 | ; perform the interpolation: |
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21 | ; dataout = total(weig*datain[addr], 1) |
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22 | ; dataout = reform(dataout, jpio, jpjo, /over) |
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23 | ; Those keywords can be set to named variables (that are undefined or equal to 0) into which the |
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24 | ; values will be copied when the current routine exits. Next, they can be used to perform |
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25 | ; the interpolation whithout computing again those 2 parameters. This greatly |
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26 | ; speed-up the interpolation! In that case, lonin, latin, lonout and latout are not necessary. |
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27 | ; |
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28 | ; @returns 2D array the interpolated data |
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29 | ; |
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30 | ; @restrictions |
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31 | ; We supposed the data are located on a sphere, with a periodicity along |
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32 | ; the longitude. |
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33 | ; Note that the input data can contain the same cells several times |
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34 | ; (like ORCA grid near the north pole boundary) |
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35 | ; |
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36 | ; @examples |
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37 | ; |
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38 | ; IDL> tncep = fromirr('bilinear', topa, glamt, gphit, tmask[*,*,0], lonout, latout, mskout) |
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39 | ; |
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40 | ; or |
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41 | ; |
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42 | ; IDL> t1ncep = fromirr('bilinear', topa, glamt, gphit, tmask[*,*,0], lonout, latout, mskout $ |
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43 | ; , WEIG = a, ADDR = b) |
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44 | ; IDL> help, a, b |
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45 | ; IDL> t2ncep = fromirr('bilinear', topa, WEIG = a, ADDR = b) |
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46 | ; |
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47 | ; @history |
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48 | ; June 2006: Sebastien Masson (smasson\@lodyc.jussieu.fr) |
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49 | ; |
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50 | ; @version $Id$ |
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51 | ; |
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52 | ;- |
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53 | ;---------------------------------------------------------- |
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54 | ;---------------------------------------------------------- |
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55 | ; |
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56 | FUNCTION fromirr, method, datain, lonin, latin, mskin, lonout, latout, mskout $ |
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57 | , WEIG = weig, ADDR = addr |
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58 | ; |
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59 | compile_opt strictarr, strictarrsubs |
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60 | ; |
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61 | ;--------------- |
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62 | ; atmospheric grid parameters |
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63 | ;--------------- |
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64 | alon = lonin |
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65 | alat = latin |
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66 | get_gridparams, alon, alat, jpia, jpja, 2, /double |
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67 | ;--------------- |
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68 | ; Oceanic grid parameters |
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69 | ;--------------- |
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70 | olon = lonout |
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71 | olat = latout |
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72 | get_gridparams, olon, olat, jpio, jpjo, 2, /double |
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73 | ;--------------- |
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74 | ; Compute weight and address |
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75 | ;--------------- |
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76 | IF NOT (keyword_set(weig) AND keyword_set(addr)) THEN BEGIN |
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77 | CASE method OF |
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78 | 'bilinear':compute_fromirr_bilinear_weigaddr, alon, alat, mskin, olon, olat, mskout, weig, addr |
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79 | ELSE:BEGIN |
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80 | print, ' unknown interpolation method... we stop' |
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81 | stop |
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82 | ENDELSE |
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83 | ENDCASE |
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84 | ENDIF |
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85 | ;--------------- |
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86 | ; to the interpolation |
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87 | ;--------------- |
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88 | dataout = total(weig*datain[addr], 1) |
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89 | dataout = reform(dataout, jpio, jpjo, /over) |
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90 | ; |
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91 | RETURN, dataout |
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92 | END |
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