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| 5 | <title>map_npoints.pro (SAXO Documentation Assistant)</title> |
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| 47 | <td width="10%"> |
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| 48 | <a href="ll_narcs_distances.html"><img src="./../prev.gif" border="0" alt="Previous"></a></td> |
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| 49 | <td width="80%" align="center" valign="center"> |
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| 50 | <font size=-1><i>SAXO Documentation Assistant</i>: <a href="./../home.html">Overview</a></font></td> |
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| 51 | <td width="10%" align="right"> |
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| 52 | <a href="neighbor.html"><img src="./../next.gif" border="0" alt="Next"></a></td> |
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| 53 | </tr> |
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| 54 | </table> |
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| 55 | |
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| 56 | |
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| 57 | <h1><font size="-2">Interpolation/</font></h1> |
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| 58 | <h2>map_npoints.pro</h2> |
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| 59 | |
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| 60 | <dl> |
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| 61 | </dl> |
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| 62 | |
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| 63 | |
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| 64 | Return the distance in meter between all np0 points P0 and all |
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| 65 | np1 points P1 on a sphere. If keyword /TWO_BY_TWO is given then |
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| 66 | returns the distances between number n of P0 points and number |
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| 67 | n of P1 points (in that case, np0 and np1 must be equal). |
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| 68 | Same as <a href="/Applications/itt/idl64/help/online_help/MAP_2POINTS.html">MAP_2POINTS</a> with the meter parameter but for n |
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| 69 | points without do loop. |
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| 70 | |
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| 71 | |
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| 72 | |
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| 73 | |
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| 74 | |
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| 75 | <a name="#_map_npoints"></a> |
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| 76 | |
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| 77 | <h2>map_npoints <font size="-1" color="#006633"> |
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| 78 | Maps |
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| 79 | </font></h2> |
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| 80 | |
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| 81 | <p><font face="Courier"><i>result = </i>map_npoints(<i><a href="#_map_npoints_keyword_lon0">lon0</a>, <a href="#_map_npoints_keyword_lat0">lat0</a>, <a href="#_map_npoints_keyword_lon1">lon1</a>, <a href="#_map_npoints_keyword_lat1">lat1</a></i>, <a href="#_map_npoints_keyword_AZIMUTH">AZIMUTH</a>=<i>AZIMUTH</i>, <a href="#_map_npoints_keyword_RADIANS">RADIANS</a>=<i>RADIANS</i>, <a href="#_map_npoints_keyword_RADIUS">RADIUS</a>=<i>RADIUS</i>, <a href="#_map_npoints_keyword_MIDDLE">MIDDLE</a>=<i>MIDDLE</i>, <a href="#_map_npoints_keyword_TWO_BY_TWO">TWO_BY_TWO</a>=<i>TWO_BY_TWO</i>)</font></p> |
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| 82 | |
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| 83 | |
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| 84 | |
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| 85 | |
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| 86 | <h3>Return value</h3> |
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| 87 | An (np0,np1) array giving the distance in meter between np0 |
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| 88 | points P0 and np1 points P1. Element (i,j) of the output is the |
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| 89 | distance between element P0[i] and P1[j]. |
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| 90 | If keyword /TWO_BY_TWO is given then <a href="..//Interpolation/map_npoints.html">map_npoints</a> returns |
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| 91 | an np-elements vector giving the distance in meter between P0[i] |
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| 92 | and P1[i] (in that case, we have np0 = np1 = np) ; if /MIDDLE see this keyword. |
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| 93 | |
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| 94 | |
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| 95 | <h3>Parameters</h3> |
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| 96 | |
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| 97 | |
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| 98 | <a name="#_map_npoints_keyword_lon0"></a> |
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| 99 | <h4>lon0 |
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| 100 | <font size="-1" color="#006633">in</font> |
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| 101 | |
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| 102 | |
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| 103 | <font size="-1" color="#006633">required</font> |
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| 104 | |
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| 105 | |
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| 106 | |
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| 107 | |
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| 108 | </h4> |
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| 109 | |
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| 110 | |
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| 111 | |
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| 112 | |
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| 113 | <a name="#_map_npoints_keyword_lat0"></a> |
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| 114 | <h4>lat0 |
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| 115 | <font size="-1" color="#006633">in</font> |
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| 116 | |
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| 117 | |
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| 118 | <font size="-1" color="#006633">required</font> |
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| 119 | |
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| 120 | |
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| 121 | |
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| 122 | |
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| 123 | </h4> |
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| 124 | |
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| 125 | |
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| 126 | np0 elements vector. longitudes and latitudes of np0 points P0 |
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| 127 | |
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| 128 | |
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| 129 | |
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| 130 | <a name="#_map_npoints_keyword_lon1"></a> |
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| 131 | <h4>lon1 |
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| 132 | <font size="-1" color="#006633">in</font> |
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| 133 | |
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| 134 | |
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| 135 | <font size="-1" color="#006633">required</font> |
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| 136 | |
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| 137 | |
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| 138 | |
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| 139 | |
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| 140 | </h4> |
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| 141 | |
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| 142 | |
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| 143 | |
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| 144 | |
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| 145 | <a name="#_map_npoints_keyword_lat1"></a> |
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| 146 | <h4>lat1 |
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| 147 | <font size="-1" color="#006633">in</font> |
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| 148 | |
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| 149 | |
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| 150 | <font size="-1" color="#006633">required</font> |
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| 151 | |
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| 152 | |
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| 153 | |
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| 154 | |
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| 155 | </h4> |
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| 156 | |
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| 157 | |
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| 158 | np1 elements vector. longitude and latitude of np1 points P1 |
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| 159 | |
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| 160 | |
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| 161 | |
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| 162 | |
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| 163 | |
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| 164 | <h3>Keywords</h3> |
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| 165 | |
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| 166 | |
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| 167 | <a name="#_map_npoints_keyword_AZIMUTH"></a> |
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| 168 | <h4>AZIMUTH |
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| 169 | |
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| 170 | |
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| 171 | |
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| 172 | |
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| 173 | |
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| 174 | |
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| 175 | |
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| 176 | |
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| 177 | </h4> |
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| 178 | |
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| 179 | |
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| 180 | A named variable that will receive the azimuth of the great |
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| 181 | circle connecting the two points, P0 to P1 |
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| 182 | |
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| 183 | |
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| 184 | <a name="#_map_npoints_keyword_RADIANS"></a> |
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| 185 | <h4>RADIANS |
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| 186 | |
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| 187 | |
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| 188 | |
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| 189 | |
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| 190 | |
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| 191 | |
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| 192 | |
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| 193 | |
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| 194 | </h4> |
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| 195 | |
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| 196 | |
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| 197 | if set, inputs and angular outputs are in radians, otherwise degrees. |
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| 198 | |
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| 199 | |
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| 200 | <a name="#_map_npoints_keyword_RADIUS"></a> |
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| 201 | <h4>RADIUS |
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| 202 | |
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| 203 | |
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| 204 | |
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| 205 | |
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| 206 | |
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| 207 | |
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| 208 | <font size="-1" color="#006633">default:</font> <font size="-1" color="#006633"><i>6378206.4d0</i></font> |
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| 209 | |
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| 210 | </h4> |
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| 211 | |
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| 212 | |
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| 213 | If given, return the distance between the two points calculated using the |
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| 214 | given radius. |
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| 215 | Default value is the Earth radius. |
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| 216 | |
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| 217 | |
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| 218 | <a name="#_map_npoints_keyword_MIDDLE"></a> |
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| 219 | <h4>MIDDLE |
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| 220 | |
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| 221 | |
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| 222 | |
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| 223 | |
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| 224 | |
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| 225 | |
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| 226 | |
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| 227 | |
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| 228 | </h4> |
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| 229 | |
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| 230 | |
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| 231 | to get the longitude/latitude of the middle point between P0 and P1. |
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| 232 | |
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| 233 | |
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| 234 | <a name="#_map_npoints_keyword_TWO_BY_TWO"></a> |
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| 235 | <h4>TWO_BY_TWO |
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| 236 | |
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| 237 | |
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| 238 | |
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| 239 | |
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| 240 | |
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| 241 | |
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| 242 | |
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| 243 | |
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| 244 | </h4> |
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| 245 | |
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| 246 | |
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| 247 | If given, then <a href="..//Interpolation/map_npoints.html">map_npoints</a> returns the distances between |
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| 248 | number n of P0 points and number n of P1 pointsi. |
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| 249 | In that case, np0 and np1 must be equal. |
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| 250 | |
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| 251 | |
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| 252 | |
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| 253 | |
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| 254 | <h3>Examples</h3><pre> |
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| 255 | IDL> print, $ |
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| 256 | IDL> map_npoints([-105.15,1],[40.02,1],[-0.07,100,50],[51.30,20,0]) |
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| 257 | 7551369.3 5600334.8 |
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| 258 | 12864354. 10921254. |
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| 259 | 14919237. 5455558.8 |
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| 260 | |
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| 261 | IDL> lon0 = [-10, 20, 100] |
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| 262 | IDL> lat0 = [0, -10, 45] |
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| 263 | IDL> lon1 = [10, 60, 280] |
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| 264 | IDL> lat1 = [0, 10, 45] |
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| 265 | IDL> dist = map_npoints(lon0, lat0, lon1, lat1, AZIMUTH = azi) |
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| 266 | IDL> help, dist, azi |
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| 267 | DIST DOUBLE = Array[3, 3] |
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| 268 | AZI DOUBLE = Array[3, 3] |
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| 269 | IDL> print, dist[4*lindgen(3)], azi[4*lindgen(3)] |
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| 270 | 2226414.0 4957944.5 10018863. |
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| 271 | 90.000000 64.494450 4.9615627e-15 |
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| 272 | IDL> dist = map_npoints(lon0, lat0, lon1, lat1, AZIMUTH = azi, /TWO_BY_TWO) |
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| 273 | IDL> help, dist, azi |
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| 274 | DIST DOUBLE = Array[3] |
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| 275 | AZI DOUBLE = Array[3] |
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| 276 | IDL> print, dist, azi |
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| 277 | 2226414.0 4957944.5 10018863. |
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| 278 | 90.000000 64.494450 4.9615627e-15 |
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| 279 | IDL> print, map_2points(lon0[0], lat0[0], lon1[0], lat1[0]) |
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| 280 | 20.000000 90.000000 |
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| 281 | IDL> print, map_npoints(lon0[0], lat0[0], lon1[0], lat1[0], AZIMUTH=azi)/6378206.4d0 / !dtor, azi |
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| 282 | 20.000000 |
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| 283 | 90.000000 |
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| 284 | |
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| 285 | IDL> lon0 = [-10, 20, 100] |
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| 286 | IDL> lat0 = [0, -10, 45] |
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| 287 | IDL> lon1 = [10, 60, 280] |
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| 288 | IDL> lat1 = [0, 10, 45] |
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| 289 | IDL> mid = map_npoints(lon0, lat0, lon1, lat1, /MIDDLE, /TWO_BY_TWO) |
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| 290 | IDL> print, reform(mid[0,*]), reform(mid[1,*]) |
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| 291 | 0.0000000 40.000000 190.00000 |
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| 292 | 0.0000000 -1.5902773e-15 90.000000 |
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| 293 | IDL> print, (map_2points(lon0[0], lat0[0], lon1[0], lat1[0], npath = 3))[*, 1] |
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| 294 | 0.0000000 0.0000000 |
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| 295 | IDL> print, (map_2points(lon0[1], lat0[1], lon1[1], lat1[1], npath = 3))[*, 1] |
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| 296 | 40.000000 -1.5902773e-15 |
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| 297 | IDL> print, (map_2points(lon0[2], lat0[2], lon1[2], lat1[2], npath = 3))[*, 1] |
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| 298 | 190.00000 90.000000 |
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| 299 | |
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| 300 | </pre><h3>Version history</h3> |
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| 301 | |
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| 302 | <h4>Version</h4> |
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| 303 | $Id: map_npoints.pro 371 2008-08-07 09:32:02Z pinsard $ |
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| 304 | |
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| 305 | <h4>History</h4> |
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| 306 | Based on the IDL function map_2points.pro,v 1.6 2001/01/15 |
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| 307 | Sebastien Masson (smasson@lodyc.jussieu.fr) |
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| 308 | October 2003 |
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| 326 | <font size="-3"><p> </p></font> |
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| 327 | <hr size="1" color="#CCCCCC"/> |
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| 332 | <p><font color="gray" size="-3"> Produced by IDLdoc 2.0.</font></p> |
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| 333 | |
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| 334 | </body> |
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| 335 | </html> |
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