1 | ;+ |
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2 | ; |
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3 | ; @file_comments |
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4 | ; to find if an (x,y) point is in a quadrilateral (x1,x2,x3,x4) |
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5 | ; |
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6 | ; @categories |
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7 | ; Grid |
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8 | ; |
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9 | ; @param x {in}{required} |
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10 | ; @param y {in}{required} |
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11 | ; the coordinates of the point we want to know where it is. |
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12 | ; Must be a scalar if /ONSPHERE activated else can be scalar or array. |
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13 | ; |
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14 | ; @param x1 {in}{required} |
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15 | ; @param y1 {in}{required} |
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16 | ; @param x2 {in}{required} |
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17 | ; @param y2 {in}{required} |
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18 | ; @param x3 {in}{required} |
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19 | ; @param y3 {in}{required} |
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20 | ; @param x4 {in}{required} |
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21 | ; @param y4 {in}{required} |
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22 | ; the coordinates of the quadrilateral given in the CLOCKWISE order. |
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23 | ; Scalar or array. |
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24 | ; |
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25 | ; @keyword DOUBLE |
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26 | ; use double precision to perform the computation |
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27 | ; |
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28 | ; @keyword ONSPHERE |
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29 | ; to specify that the quadrilateral are on a sphere and |
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30 | ; that their coordinates are longitude-latitude coordinates. In this |
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31 | ; case, east-west periodicity, poles singularity and other pbs |
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32 | ; related to longitude-latitude coordinates are managed |
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33 | ; automatically. |
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34 | ; |
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35 | ; @keyword DELTA {default=4} |
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36 | ; to speed up the program, we reduce the aera where we look for potential |
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37 | ; quadrilaterals containing (x,y). Delta defines the limit of the box |
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38 | ; centred on (x,y) with a zonal and meridional extent of delta degrees. |
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39 | ; |
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40 | ; @keyword NOPRINT |
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41 | ; to suppress the print messages. |
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42 | ; |
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43 | ; @keyword NEWCOORD |
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44 | ; |
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45 | ; @returns |
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46 | ; a n elements vector where n is the number of elements of |
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47 | ; x. res[i]=j means that the point number i is located in the |
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48 | ; quadrilateral number j with (0 <= j <= n_elements(x0)-1) |
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49 | ; |
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50 | ; @restrictions |
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51 | ; I think degenerated quadrilateral (e.g. flat of twisted) is not work. |
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52 | ; This has to be tested. |
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53 | ; |
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54 | ; @examples |
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55 | ; |
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56 | ; IDL> x = 1.*[1, 2, 6, 7, 3] |
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57 | ; IDL> y = 1.*[1, 3, 3, 4, 7] |
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58 | ; IDL> x1 = 1.*[0,4,2] |
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59 | ; IDL> y1 = 1.*[1,4,8] |
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60 | ; IDL> x2 = 1.*[1,6,4] |
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61 | ; IDL> y2 = 1.*[5,6,8] |
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62 | ; IDL> x3 = 1.*[3,8,4] |
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63 | ; IDL> y3 = 1.*[4,4,6] |
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64 | ; IDL> x4 = 1.*[2,6,2] |
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65 | ; IDL> y4 = 1.*[0,2,6] |
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66 | ; IDL> splot, [0,10], [0,10], xstyle = 1, ystyle = 1,/nodata |
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67 | ; IDL> for i=0,2 do oplot, [x4[i],x1[i],x2[i],x3[i],x4[i]],[y4[i],y1[i],y2[i],y3[i],y4[i]] |
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68 | ; IDL> oplot, x, y, color = 20, psym = 1, thick = 2 |
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69 | ; IDL> print, inquad(x, y, x1, y1, x2, y2, x3, y3, x4, y4) |
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70 | ; |
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71 | ; On a sphere see |
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72 | ; <pro>clickincell</pro> ... |
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73 | ; |
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74 | ; @history |
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75 | ; Sebastien Masson (smasson\@lodyc.jussieu.fr) |
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76 | ; August 2003 |
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77 | ; Based on Convert_clic_ij.pro written by Gurvan Madec |
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78 | ; |
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79 | ; @version |
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80 | ; $Id$ |
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81 | ; |
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82 | ;- |
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83 | FUNCTION inquad, x, y, x1, y1, x2, y2, x3, y3, x4, y4 $ |
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84 | , ONSPHERE=onsphere, DOUBLE=double, DELTA=delta $ |
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85 | , NOPRINT=noprint, NEWCOORD=newcoord |
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86 | ; |
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87 | compile_opt idl2, strictarrsubs |
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88 | ; |
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89 | ntofind = n_elements(x) |
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90 | nquad = n_elements(x2) |
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91 | ; |
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92 | IF keyword_set(onsphere) THEN BEGIN |
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93 | ; save the inputs parameters |
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94 | xin = x |
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95 | yin = y |
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96 | x1in = x1 |
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97 | y1in = y1 |
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98 | x2in = x2 |
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99 | y2in = y2 |
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100 | x3in = x3 |
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101 | y3in = y3 |
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102 | x4in = x4 |
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103 | y4in = y4 |
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104 | ; for map_set |
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105 | x = x MOD 360 |
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106 | x1 = x1 MOD 360 |
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107 | x2 = x2 MOD 360 |
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108 | x3 = x3 MOD 360 |
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109 | x4 = x4 MOD 360 |
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110 | ; save !map |
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111 | save = {map:!map, x:!x, y:!y, z:!z, p:!p} |
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112 | ; do a satellite projection |
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113 | IF NOT keyword_set(delta) THEN delta = 4 |
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114 | map_set, y[0], x[0], 0, /stereo, limit = [y[0]-delta/2, x[0]-delta/2, y[0]+delta/2, x[0]+delta/2], /noerase, /iso, /noborder |
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115 | ; use normal coordinates to reject cells which are out of the projection. |
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116 | tmp = convert_coord(x, y, /DATA, /TO_NORMAL, DOUBLE = double) |
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117 | tmp1 = convert_coord(x1, y1, /DATA, /TO_NORMAL, DOUBLE = double) |
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118 | tmp2 = convert_coord(x2, y2, /DATA, /TO_NORMAL, DOUBLE = double) |
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119 | tmp3 = convert_coord(x3, y3, /DATA, /TO_NORMAL, DOUBLE = double) |
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120 | tmp4 = convert_coord(x4, y4, /DATA, /TO_NORMAL, DOUBLE = double) |
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121 | ; remove cell which have one corner with coordinates equal to NaN |
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122 | test = finite(tmp1[0, *]+tmp1[1, *]+tmp2[0, *]+tmp2[1, *] $ |
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123 | +tmp3[0, *]+tmp3[1, *]+tmp4[0, *]+tmp4[1, *]) |
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124 | good = where(temporary(test) EQ 1) |
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125 | ; |
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126 | IF good[0] EQ -1 THEN BEGIN |
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127 | IF NOT keyword_set(noprint) THEN BEGIN |
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128 | ras = report('The point is out of the cells') |
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129 | ENDIF |
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130 | ; restore the input parameters |
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131 | x = temporary(xin) |
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132 | y = temporary(yin) |
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133 | x1 = temporary(x1in) |
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134 | y1 = temporary(y1in) |
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135 | x2 = temporary(x2in) |
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136 | y2 = temporary(y2in) |
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137 | x3 = temporary(x3in) |
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138 | y3 = temporary(y3in) |
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139 | x4 = temporary(x4in) |
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140 | y4 = temporary(y4in) |
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141 | ; restore old !map... |
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142 | !map = save.map |
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143 | !x = save.x |
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144 | !y = save.y |
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145 | !z = save.z |
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146 | !p = save.p |
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147 | RETURN, -1 |
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148 | ENDIF |
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149 | ; |
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150 | x = tmp[0] |
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151 | y = tmp[1] |
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152 | x1 = tmp1[0, good] |
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153 | y1 = tmp1[1, good] |
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154 | x2 = tmp2[0, good] |
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155 | y2 = tmp2[1, good] |
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156 | x3 = tmp3[0, good] |
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157 | y3 = tmp3[1, good] |
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158 | x4 = tmp4[0, good] |
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159 | y4 = tmp4[1, good] |
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160 | ; |
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161 | tmp1 = -1 & tmp2 = -1 & tmp3 = -1 & tmp4 = -1 |
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162 | ; remove cells which are obviously bad |
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163 | test = (x1 GT x AND x2 GT x AND x3 GT x AND x4 GT x) $ |
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164 | OR (x1 LT x AND x2 LT x AND x3 LT x AND x4 LT x) $ |
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165 | OR (y1 GT y AND y2 GT y AND y3 GT y AND y4 GT y) $ |
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166 | OR (y1 LT y AND y2 LT y AND y3 LT y AND y4 LT y) |
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167 | good2 = where(temporary(test) EQ 0) |
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168 | ; |
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169 | IF good2[0] EQ -1 THEN BEGIN |
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170 | IF NOT keyword_set(noprint) THEN BEGIN |
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171 | ras = report('The point is out of the cells') |
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172 | ENDIF |
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173 | ; restore the input parameters |
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174 | x = temporary(xin) |
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175 | y = temporary(yin) |
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176 | x1 = temporary(x1in) |
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177 | y1 = temporary(y1in) |
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178 | x2 = temporary(x2in) |
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179 | y2 = temporary(y2in) |
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180 | x3 = temporary(x3in) |
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181 | y3 = temporary(y3in) |
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182 | x4 = temporary(x4in) |
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183 | y4 = temporary(y4in) |
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184 | ; restore old !map... |
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185 | !map = save.map |
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186 | !x = save.x |
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187 | !y = save.y |
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188 | !z = save.z |
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189 | !p = save.p |
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190 | RETURN, -1 |
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191 | ENDIF |
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192 | ; |
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193 | nquad = n_elements(good2) |
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194 | x1 = x1[good2] |
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195 | y1 = y1[good2] |
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196 | x2 = x2[good2] |
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197 | y2 = y2[good2] |
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198 | x3 = x3[good2] |
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199 | y3 = y3[good2] |
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200 | x4 = x4[good2] |
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201 | y4 = y4[good2] |
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202 | ENDIF |
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203 | ; |
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204 | ; |
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205 | ; the point is inside the quadrilateral if test eq 1 |
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206 | ; with test equal to: |
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207 | ; test = ((x-x1)*(y2-y1) GE (x2-x1)*(y-y1)) $ |
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208 | ; *((x-x2)*(y3-y2) GT (x3-x2)*(y-y2)) $ |
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209 | ; *((x-x3)*(y4-y3) GT (x4-x3)*(y-y3)) $ |
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210 | ; *((x-x4)*(y1-y4) GE (x1-x4)*(y-y4)) |
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211 | ; |
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212 | ; computation of test without any do loop for ntofind points (x,y) and |
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213 | ; nquad quadrilateral((x1,x2,x3,x4),(y1,y2,y3,y4)) |
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214 | ; test dimensions are (ntofind, nquad) |
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215 | ; column i of test corresponds to the intersection of point i with all |
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216 | ; quadrilateral. |
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217 | ; row j of test corresponds to all the points localized in cell j |
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218 | |
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219 | IF keyword_set(double) THEN one = 1.d ELSE one = 1. |
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220 | nquad_1 = replicate(one, nquad) |
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221 | ntofind_1 = replicate(one, ntofind) |
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222 | x_nquad = x[*]#replicate(one, nquad) |
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223 | y_nquad = y[*]#replicate(one, nquad) |
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224 | |
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225 | test = $ |
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226 | ; (x-x1)*(y2-y1) GE (x2-x1)*(y-y1) |
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227 | ( (x_nquad - ntofind_1#x1[*]) * (ntofind_1#(y2-y1)[*]) ) GE ( (ntofind_1#(x2-x1)[*]) * (y_nquad - ntofind_1#y1[*]) ) AND $ |
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228 | ; *(x-x2)*(y3-y2) GE (x3-x2)*(y-y2) |
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229 | ( (x_nquad - ntofind_1#x2[*]) * (ntofind_1#(y3-y2)[*]) ) GE ( (ntofind_1#(x3-x2)[*]) * (y_nquad - ntofind_1#y2[*]) ) AND $ |
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230 | ; *(x-x3)*(y4-y3) GE (x4-x3)*(y-y3) |
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231 | ( (x_nquad - ntofind_1#x3[*]) * (ntofind_1#(y4-y3)[*]) ) GE ( (ntofind_1#(x4-x3)[*]) * (y_nquad - ntofind_1#y3[*]) ) AND $ |
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232 | ; *(x-x4)*(y1-y4) GE (x1-x4)*(y-y4) |
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233 | ( (x_nquad - ntofind_1#x4[*]) * (ntofind_1#(y1-y4)[*]) ) GE ( (ntofind_1#(x1-x4)[*]) * (y_nquad - ntofind_1#y4[*]) ) |
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234 | ; |
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235 | nquad_1 = 1 & ntofind_1 = 1 & x_nquad = 1 & y_nquad = 1 ; free memory |
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236 | ; |
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237 | ; check test if ntofind gt 1 |
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238 | ; if ntofind gt 1, each point must be localised in one uniq cell. |
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239 | IF ntofind GT 1 THEN BEGIN |
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240 | ; each column of test must have only 1 position equal to one |
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241 | chtest = total(test, 2) |
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242 | ; points out of the cells |
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243 | IF (where(chtest EQ 0))[0] NE -1 THEN BEGIN |
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244 | IF NOT keyword_set(noprint) THEN BEGIN |
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245 | ras = report('Points number '+strjoin(strtrim(where(chtest EQ 0), 1), ', ')+' are out of the grid') |
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246 | ENDIF |
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247 | stop |
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248 | ENDIF |
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249 | ; points in more than one cell |
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250 | IF (where(chtest GT 1))[0] NE -1 THEN BEGIN |
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251 | IF NOT keyword_set(noprint) THEN BEGIN |
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252 | ras = report('Points number '+strjoin(strtrim(where(chtest GT 1), 1), ', ')+' are in more than one cell') |
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253 | ENDIF |
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254 | stop |
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255 | ENDIF |
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256 | ENDIF |
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257 | ; find the points for which test eq 1 |
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258 | found = where(temporary(test) EQ 1) |
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259 | ; if ntofind eq 1, the point may be localised in more than one grid |
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260 | ; cell ou may also be out of the cells |
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261 | IF ntofind EQ 1 THEN BEGIN |
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262 | CASE 1 OF |
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263 | found[0] EQ -1:BEGIN |
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264 | IF NOT keyword_set(noprint) THEN BEGIN |
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265 | ras = report('The point is out of the cells') |
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266 | ENDIF |
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267 | IF keyword_set(onsphere) THEN BEGIN |
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268 | ; restore old !map... |
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269 | !map = save.map |
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270 | !x = save.x |
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271 | !y = save.y |
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272 | !z = save.z |
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273 | !p = save.p |
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274 | ENDIF |
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275 | return, -1 |
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276 | END |
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277 | n_elements(found) GT ntofind:BEGIN |
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278 | IF NOT keyword_set(noprint) THEN BEGIN |
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279 | ras = report('The point is in more than one cell') |
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280 | ENDIF |
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281 | END |
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282 | ELSE: |
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283 | ENDCASE |
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284 | ENDIF ELSE BEGIN |
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285 | ; if ntofind GT 1, found must be sorted |
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286 | ; i position of found. this corresponds to one x,y point |
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287 | forsort = found MOD ntofind |
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288 | ; j position of found. this corresponds to cell in which is one x,y |
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289 | ; point |
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290 | found = temporary(found)/ntofind |
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291 | ; found must be sorted according to forsort |
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292 | found = found[sort(forsort)] |
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293 | ENDELSE |
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294 | ; |
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295 | IF keyword_set(onsphere) THEN BEGIN |
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296 | IF arg_present(newcoord) THEN BEGIN |
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297 | found = found[0] |
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298 | newcoord = [[x1[found], y1[found]] $ |
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299 | , [x2[found], y2[found]] $ |
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300 | , [x3[found], y3[found]] $ |
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301 | , [x4[found], y4[found]] $ |
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302 | , [x, y]] |
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303 | ENDIF |
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304 | ; |
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305 | found = good[good2[found]] |
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306 | ; restore the input parameters |
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307 | x = temporary(xin) |
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308 | y = temporary(yin) |
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309 | x1 = temporary(x1in) |
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310 | y1 = temporary(y1in) |
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311 | x2 = temporary(x2in) |
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312 | y2 = temporary(y2in) |
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313 | x3 = temporary(x3in) |
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314 | y3 = temporary(y3in) |
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315 | x4 = temporary(x4in) |
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316 | y4 = temporary(y4in) |
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317 | ; restore old !map... |
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318 | !map = save.map |
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319 | !x = save.x |
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320 | !y = save.y |
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321 | !z = save.z |
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322 | !p = save.p |
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323 | ENDIF |
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324 | ; |
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325 | RETURN, found |
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326 | END |
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