1 | ; 1.1 01/10/07 |
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2 | |
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3 | ; Work out the "dimensions" to a structure for writing |
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4 | ; to netcdf file, based on some simplistic rules which |
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5 | ; fail if more than one dimension has the same length |
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6 | ; |
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7 | ; Where by these rules it is not obvious which should be |
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8 | ; dimensions and which variables relate to which dimension |
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9 | ; there are two options - either a quick and dirty fix, or |
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10 | ; tediously indicating and linking dimensions by hand: |
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11 | ; |
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12 | ; DIM_ALL - just flags all vectors as dimensions in the |
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13 | ; netcdf file. The NetCDF linkage between dimensions |
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14 | ; and variables will be broken and should be ignored. |
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15 | ; This is fine if you're planning on no more than |
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16 | ; reading the data into an IDL structure again, but |
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17 | ; will produce confusing results with ncdump |
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18 | ; |
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19 | ; DIMENSIONS - A structure indicating dimensions and |
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20 | ; the dimensions applying to variables, up to |
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21 | ; a maximum of five. E.g. when there are four |
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22 | ; elements in the IDL structure (the netcdf_write.pro |
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23 | ; example): |
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24 | ; |
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25 | ; dimensions = {isdim:intarr(4), links:intarr(5,4)} |
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26 | ; dimensions.isdim = [1,1,1,0] ; (1=dimension, 0=variable) |
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27 | ; dimensions.links = [[-1,-1,-1,-1,-1],[-1,-1,-1,-1,-1],$ |
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28 | ; [-1,-1,-1,-1,-1],[0,1,2,-1,-1]] |
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29 | ; |
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30 | ; Run through all data "tags" to identify "dimensions" and |
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31 | ; "variables". For this to work, the data structure must always |
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32 | ; have dimensions before normal variables |
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33 | ; |
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34 | ; AJG 31/7/06 extracted from netcdf_write.pro |
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35 | ; |
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36 | pro struct_dims, field, dimension_sizes, is_string_max, var_type, $ |
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37 | nDimensions, dim_num, iDimLink, dim_all=dim_all, dimensions=dimensions |
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38 | |
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39 | ; Output codes from the IDL SIZE routine - numerical types |
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40 | ; that we may convert to float in our simplistic universe |
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41 | ; though there may be some truncation of information |
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42 | ; (e.g. 64bit int reduced to float). Simplistic universe now |
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43 | ; includes treatment of doubles, though (essential for Julian time) |
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44 | valid_float = [1,2,3,4,5,12,13,14,15] |
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45 | |
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46 | ; We can make a special (and difficult) exception for string data, |
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47 | ; too, but only string vectors at the moment. See NetCDF user's |
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48 | ; guide, "reading and writing character string values". Also |
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49 | ; IDL online help "String data in NetCDF files" |
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50 | valid_string = [7] |
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51 | |
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52 | ; Find tag names and number |
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53 | tag_names = tag_names(field) |
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54 | nTags = N_TAGS(field) |
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55 | |
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56 | ; Output data: information on what we think are dimensions and |
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57 | ; variables |
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58 | dimension_sizes = lonarr(nTags) ; Made long not int for big files! |
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59 | is_string_max = intarr(nTags) ; 0=not a string; >0=max string length |
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60 | var_type = intarr(nTags) ; Variable type based on the output of SIZE |
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61 | nDimensions = 0 |
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62 | dim_num = intarr(nTags) |
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63 | iDimlink = intarr(nTags,5) ; up to 5D currently |
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64 | |
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65 | ; First pass - identify dimensions. All dimensions must |
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66 | ; be vectors. Also identifies variables, and flags string data |
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67 | for iTag=0, nTags-1 do begin |
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68 | |
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69 | tag_size = size(field.(iTag)) |
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70 | var_type[iTag] = size(field.(iTag),/type) |
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71 | |
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72 | if tag_size[0] le 1 then begin |
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73 | |
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74 | ; We have found a vector (tag_size[0]=1) or a scalar (=0) |
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75 | ; which we will treat as a 1D 1 element vector. The |
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76 | ; following rules apply: If it's a numerical vector, it |
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77 | ; is a dimension only if it's the first of that size. |
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78 | ; Following vectors of the same size will be treated as |
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79 | ; variables. (unless keyword DIM_ALL is set) |
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80 | |
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81 | ; If scalar pretend it's a 1D 1 element vector |
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82 | if tag_size[0] eq 0 then begin |
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83 | tag_size[0] = 1 |
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84 | tag_size[1] = 1 |
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85 | endif |
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86 | |
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87 | iTemp = where( var_type[iTag] eq valid_float, count) |
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88 | if count gt 0 then begin |
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89 | |
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90 | ; We have a numerical value that will be treated as FLOAT or DOUBLE |
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91 | |
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92 | ; Is this a dimension? |
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93 | bDim = 0 |
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94 | |
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95 | ; (a) If it's the first vector of this length found |
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96 | iTemp = where( tag_size[1] eq dimension_sizes, count) |
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97 | if count eq 0 then bDim = 1 |
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98 | |
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99 | ; (b) If the DIM_ALL keyword is set (all vectors treated as dimensions) |
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100 | if keyword_set(DIM_ALL) then bDim = 1 |
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101 | |
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102 | ; (c) If indicated by the DIMENSIONS structure |
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103 | if keyword_set(DIMENSIONS) then begin |
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104 | if dimensions.isdim[iTag] then bDim = 1 |
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105 | endif |
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106 | |
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107 | if bDim then begin |
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108 | |
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109 | ; We have found a new dimension |
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110 | dimension_sizes[iTag] = tag_size[1] |
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111 | dim_num[iTag] = 0 ; indicates this IS a dimension |
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112 | nDimensions = nDimensions + 1 |
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113 | |
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114 | endif else begin |
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115 | |
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116 | ; This is a variable |
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117 | dim_num[iTag] = tag_size[0] ; number of dimensions linked |
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118 | |
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119 | endelse |
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120 | |
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121 | endif else begin |
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122 | |
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123 | iTemp = where( tag_size[2] eq valid_string, count) |
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124 | if count eq 1 then begin |
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125 | |
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126 | ; This is a variable, but it's a string array |
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127 | ; which needs special treatment |
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128 | dim_num[iTag] = tag_size[0] ; number of dimensions linked* |
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129 | is_string_max[iTag] = max(strlen(field.(iTag))) |
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130 | |
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131 | ; * Note that a string variable will gain an extra, hidden |
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132 | ; dimension when we write it to file because of NetCDF |
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133 | ; limitations. |
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134 | |
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135 | ; NB also that a string array cannot be a dimension. |
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136 | |
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137 | endif else begin |
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138 | message, "Data type not supported for "+tag_names[iTag] |
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139 | endelse |
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140 | endelse |
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141 | |
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142 | endif else begin |
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143 | |
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144 | ; This is a 2D or more variable |
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145 | dim_num[iTag] = tag_size[0] ; number of dimensions applicable |
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146 | |
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147 | endelse |
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148 | endfor |
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149 | |
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150 | ; Second pass - link variables to dimensions |
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151 | for iTag=0, nTags-1 do begin |
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152 | |
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153 | tag_size = size(field.(iTag)) |
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154 | |
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155 | ; Is it a variable? |
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156 | if dim_num[iTag] ne 0 then begin |
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157 | |
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158 | ; If scalar pretend it's a 1D 1 element vector |
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159 | if tag_size[0] eq 0 then begin |
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160 | tag_size[0] = 1 |
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161 | tag_size[1] = 1 |
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162 | endif |
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163 | |
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164 | ; find which dimensions apply to this variable by finding |
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165 | ; vectors of the same length as the array dimensions |
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166 | for iDim = 0, tag_size[0]-1 do begin |
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167 | |
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168 | if keyword_set(DIMENSIONS) then begin |
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169 | |
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170 | ; Caller has explicitly specified the dimensions and links |
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171 | iDimlink[iTag,iDim] = dimensions.links[iDim,iTag] |
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172 | |
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173 | endif else begin |
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174 | |
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175 | ; Assign dimensions on a first come first served basis. |
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176 | ; by matching sizes. This works fine until you have two |
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177 | ; dimensions the same size. Use DIM_ALL or DIMENSIONS in that case |
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178 | iDimSizeEqual = where(dimension_sizes eq tag_size[iDim+1], count) |
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179 | if count ne 0 then begin |
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180 | if count eq 1 then begin |
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181 | iDimlink[iTag,iDim] = iDimSizeEqual[0] |
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182 | endif else begin |
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183 | ; Work out which dimension applies if more than one is of |
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184 | ; identical length: do this by order. |
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185 | iTagSizeEqual = where(tag_size eq tag_size[iDim+1], tag_ct) |
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186 | if tag_ct eq 1 then begin |
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187 | iDimlink[iTag,iDim] = iDimSizeEqual[0] |
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188 | endif else begin |
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189 | tag_order = where(iTagSizeEqual eq iDim+1) |
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190 | iDimlink[iTag,iDim] = iDimSizeEqual[tag_order] |
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191 | endelse |
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192 | endelse |
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193 | endif else begin |
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194 | message, "Matching dimension not found for "+tag_names[iTag] |
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195 | endelse |
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196 | |
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197 | endelse |
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198 | |
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199 | endfor |
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200 | |
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201 | endif |
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202 | |
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203 | endfor |
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204 | |
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205 | end |
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206 | |
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