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   4 <title>return_centroid (with strategy)</title>
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  26 <div class="titlepage"><div><div><h5 class="title">
  27 <a name="geometry.reference.algorithms.centroid.return_centroid_2_with_strategy"></a><a class="link" href="return_centroid_2_with_strategy.html" title="return_centroid (with strategy)">return_centroid
  28           (with strategy)</a>
  29 </h5></div></div></div>
  30 <p>
  31             <a class="indexterm" name="idm46187006950608"></a>
  32 Calculates the centroid of a geometry using the specified strategy.
  33           </p>
  34 <h6>
  35 <a name="geometry.reference.algorithms.centroid.return_centroid_2_with_strategy.h0"></a>
  36             <span class="phrase"><a name="geometry.reference.algorithms.centroid.return_centroid_2_with_strategy.description"></a></span><a class="link" href="return_centroid_2_with_strategy.html#geometry.reference.algorithms.centroid.return_centroid_2_with_strategy.description">Description</a>
  37           </h6>
  38 <p>
  39             The free function centroid calculates the geometric center (or: center
  40             of mass) of a geometry. This version with the return_ prefix returns
  41             the centroid, and a template parameter must therefore be specified in
  42             the call.. Reasons to specify a strategy include: use another coordinate
  43             system for calculations; construct the strategy beforehand (e.g. with
  44             the radius of the Earth); select a strategy when there are more than
  45             one available for a calculation.
  46           </p>
  47 <h6>
  48 <a name="geometry.reference.algorithms.centroid.return_centroid_2_with_strategy.h1"></a>
  49             <span class="phrase"><a name="geometry.reference.algorithms.centroid.return_centroid_2_with_strategy.synopsis"></a></span><a class="link" href="return_centroid_2_with_strategy.html#geometry.reference.algorithms.centroid.return_centroid_2_with_strategy.synopsis">Synopsis</a>
  50           </h6>
  51 <p>
  52 </p>
  53 <pre class="programlisting"><span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">typename</span> <span class="identifier">Point</span><span class="special">,</span> <span class="keyword">typename</span> <span class="identifier">Geometry</span><span class="special">,</span> <span class="keyword">typename</span> <span class="identifier">Strategy</span><span class="special">&gt;</span>
  54 <span class="identifier">Point</span> <span class="identifier">return_centroid</span><span class="special">(</span><span class="identifier">Geometry</span> <span class="keyword">const</span> <span class="special">&amp;</span> <span class="identifier">geometry</span><span class="special">,</span> <span class="identifier">Strategy</span> <span class="keyword">const</span> <span class="special">&amp;</span> <span class="identifier">strategy</span><span class="special">)</span></pre>
  55 <p>
  56           </p>
  57 <h6>
  58 <a name="geometry.reference.algorithms.centroid.return_centroid_2_with_strategy.h2"></a>
  59             <span class="phrase"><a name="geometry.reference.algorithms.centroid.return_centroid_2_with_strategy.parameters"></a></span><a class="link" href="return_centroid_2_with_strategy.html#geometry.reference.algorithms.centroid.return_centroid_2_with_strategy.parameters">Parameters</a>
  60           </h6>
  61 <div class="informaltable"><table class="table">
  62 <colgroup>
  63 <col>
  64 <col>
  65 <col>
  66 <col>
  67 </colgroup>
  68 <thead><tr>
  69 <th>
  70                     <p>
  71                       Type
  72                     </p>
  73                   </th>
  74 <th>
  75                     <p>
  76                       Concept
  77                     </p>
  78                   </th>
  79 <th>
  80                     <p>
  81                       Name
  82                     </p>
  83                   </th>
  84 <th>
  85                     <p>
  86                       Description
  87                     </p>
  88                   </th>
  89 </tr></thead>
  90 <tbody>
  91 <tr>
  92 <td>
  93                     <p>
  94                       Point
  95                     </p>
  96                   </td>
  97 <td>
  98                     <p>
  99                       Any type fulfilling a Point Concept
 100                     </p>
 101                   </td>
 102 <td>
 103                     <p>
 104                       -
 105                     </p>
 106                   </td>
 107 <td>
 108                     <p>
 109                       Must be specified
 110                     </p>
 111                   </td>
 112 </tr>
 113 <tr>
 114 <td>
 115                     <p>
 116                       Geometry const &amp;
 117                     </p>
 118                   </td>
 119 <td>
 120                     <p>
 121                       Any type fulfilling a Geometry Concept
 122                     </p>
 123                   </td>
 124 <td>
 125                     <p>
 126                       geometry
 127                     </p>
 128                   </td>
 129 <td>
 130                     <p>
 131                       A model of the specified concept
 132                     </p>
 133                   </td>
 134 </tr>
 135 <tr>
 136 <td>
 137                     <p>
 138                       Strategy const &amp;
 139                     </p>
 140                   </td>
 141 <td>
 142                     <p>
 143                       Any type fulfilling a centroid Strategy Concept
 144                     </p>
 145                   </td>
 146 <td>
 147                     <p>
 148                       strategy
 149                     </p>
 150                   </td>
 151 <td>
 152                     <p>
 153                       The strategy which will be used for centroid calculations
 154                     </p>
 155                   </td>
 156 </tr>
 157 </tbody>
 158 </table></div>
 159 <h6>
 160 <a name="geometry.reference.algorithms.centroid.return_centroid_2_with_strategy.h3"></a>
 161             <span class="phrase"><a name="geometry.reference.algorithms.centroid.return_centroid_2_with_strategy.returns"></a></span><a class="link" href="return_centroid_2_with_strategy.html#geometry.reference.algorithms.centroid.return_centroid_2_with_strategy.returns">Returns</a>
 162           </h6>
 163 <p>
 164             The calculated centroid
 165           </p>
 166 <h6>
 167 <a name="geometry.reference.algorithms.centroid.return_centroid_2_with_strategy.h4"></a>
 168             <span class="phrase"><a name="geometry.reference.algorithms.centroid.return_centroid_2_with_strategy.header"></a></span><a class="link" href="return_centroid_2_with_strategy.html#geometry.reference.algorithms.centroid.return_centroid_2_with_strategy.header">Header</a>
 169           </h6>
 170 <p>
 171             Either
 172           </p>
 173 <p>
 174             <code class="computeroutput"><span class="preprocessor">#include</span> <span class="special">&lt;</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">geometry</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">&gt;</span></code>
 175           </p>
 176 <p>
 177             Or
 178           </p>
 179 <p>
 180             <code class="computeroutput"><span class="preprocessor">#include</span> <span class="special">&lt;</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">geometry</span><span class="special">/</span><span class="identifier">algorithms</span><span class="special">/</span><span class="identifier">centroid</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">&gt;</span></code>
 181           </p>
 182 <h6>
 183 <a name="geometry.reference.algorithms.centroid.return_centroid_2_with_strategy.h5"></a>
 184             <span class="phrase"><a name="geometry.reference.algorithms.centroid.return_centroid_2_with_strategy.conformance"></a></span><a class="link" href="return_centroid_2_with_strategy.html#geometry.reference.algorithms.centroid.return_centroid_2_with_strategy.conformance">Conformance</a>
 185           </h6>
 186 <p>
 187             The function centroid implements function Centroid from the <a href="http://www.opengeospatial.org/standards/sfa" target="_top">OGC
 188             Simple Feature Specification</a>.
 189           </p>
 190 <h6>
 191 <a name="geometry.reference.algorithms.centroid.return_centroid_2_with_strategy.h6"></a>
 192             <span class="phrase"><a name="geometry.reference.algorithms.centroid.return_centroid_2_with_strategy.behavior"></a></span><a class="link" href="return_centroid_2_with_strategy.html#geometry.reference.algorithms.centroid.return_centroid_2_with_strategy.behavior">Behavior</a>
 193           </h6>
 194 <div class="informaltable"><table class="table">
 195 <colgroup>
 196 <col>
 197 <col>
 198 </colgroup>
 199 <thead><tr>
 200 <th>
 201                     <p>
 202                       Case
 203                     </p>
 204                   </th>
 205 <th>
 206                     <p>
 207                       Behavior
 208                     </p>
 209                   </th>
 210 </tr></thead>
 211 <tbody>
 212 <tr>
 213 <td>
 214                     <p>
 215                       Point
 216                     </p>
 217                   </td>
 218 <td>
 219                     <p>
 220                       Returns the point itself as the centroid
 221                     </p>
 222                   </td>
 223 </tr>
 224 <tr>
 225 <td>
 226                     <p>
 227                       Multi Point
 228                     </p>
 229                   </td>
 230 <td>
 231                     <p>
 232                       Calculates centroid (based on average)
 233                     </p>
 234                   </td>
 235 </tr>
 236 <tr>
 237 <td>
 238                     <p>
 239                       linear (e.g. linestring)
 240                     </p>
 241                   </td>
 242 <td>
 243                     <p>
 244                       Calculates centroid (based on weighted length)
 245                     </p>
 246                   </td>
 247 </tr>
 248 <tr>
 249 <td>
 250                     <p>
 251                       areal (e.g. polygon)
 252                     </p>
 253                   </td>
 254 <td>
 255                     <p>
 256                       Calculates centroid
 257                     </p>
 258                   </td>
 259 </tr>
 260 <tr>
 261 <td>
 262                     <p>
 263                       Empty (e.g. polygon without points)
 264                     </p>
 265                   </td>
 266 <td>
 267                     <p>
 268                       Throws a <a class="link" href="../../exceptions/centroid_exception.html" title="centroid_exception">centroid_exception</a>
 269                     </p>
 270                   </td>
 271 </tr>
 272 <tr>
 273 <td>
 274                     <p>
 275                       Cartesian
 276                     </p>
 277                   </td>
 278 <td>
 279                     <p>
 280                       Implemented
 281                     </p>
 282                   </td>
 283 </tr>
 284 <tr>
 285 <td>
 286                     <p>
 287                       Spherical
 288                     </p>
 289                   </td>
 290 <td>
 291                     <p>
 292                       Calculates the centroid as if based on Cartesian coordinates
 293                     </p>
 294                   </td>
 295 </tr>
 296 </tbody>
 297 </table></div>
 298 <h6>
 299 <a name="geometry.reference.algorithms.centroid.return_centroid_2_with_strategy.h7"></a>
 300             <span class="phrase"><a name="geometry.reference.algorithms.centroid.return_centroid_2_with_strategy.supported_geometries"></a></span><a class="link" href="return_centroid_2_with_strategy.html#geometry.reference.algorithms.centroid.return_centroid_2_with_strategy.supported_geometries">Supported
 301             geometries</a>
 302           </h6>
 303 <div class="informaltable"><table class="table">
 304 <colgroup>
 305 <col>
 306 <col>
 307 <col>
 308 </colgroup>
 309 <thead><tr>
 310 <th>
 311                   </th>
 312 <th>
 313                     <p>
 314                       2D
 315                     </p>
 316                   </th>
 317 <th>
 318                     <p>
 319                       3D
 320                     </p>
 321                   </th>
 322 </tr></thead>
 323 <tbody>
 324 <tr>
 325 <td>
 326                     <p>
 327                       Point
 328                     </p>
 329                   </td>
 330 <td>
 331                     <p>
 332                       <span class="inlinemediaobject"><img src="../../../../img/ok.png" alt="ok"></span>
 333                     </p>
 334                   </td>
 335 <td>
 336                     <p>
 337                       <span class="inlinemediaobject"><img src="../../../../img/ok.png" alt="ok"></span>
 338                     </p>
 339                   </td>
 340 </tr>
 341 <tr>
 342 <td>
 343                     <p>
 344                       Segment
 345                     </p>
 346                   </td>
 347 <td>
 348                     <p>
 349                       <span class="inlinemediaobject"><img src="../../../../img/ok.png" alt="ok"></span>
 350                     </p>
 351                   </td>
 352 <td>
 353                     <p>
 354                       <span class="inlinemediaobject"><img src="../../../../img/ok.png" alt="ok"></span>
 355                     </p>
 356                   </td>
 357 </tr>
 358 <tr>
 359 <td>
 360                     <p>
 361                       Box
 362                     </p>
 363                   </td>
 364 <td>
 365                     <p>
 366                       <span class="inlinemediaobject"><img src="../../../../img/ok.png" alt="ok"></span>
 367                     </p>
 368                   </td>
 369 <td>
 370                     <p>
 371                       <span class="inlinemediaobject"><img src="../../../../img/ok.png" alt="ok"></span>
 372                     </p>
 373                   </td>
 374 </tr>
 375 <tr>
 376 <td>
 377                     <p>
 378                       Linestring
 379                     </p>
 380                   </td>
 381 <td>
 382                     <p>
 383                       <span class="inlinemediaobject"><img src="../../../../img/ok.png" alt="ok"></span>
 384                     </p>
 385                   </td>
 386 <td>
 387                     <p>
 388                       <span class="inlinemediaobject"><img src="../../../../img/nyi.png" alt="nyi"></span>
 389                     </p>
 390                   </td>
 391 </tr>
 392 <tr>
 393 <td>
 394                     <p>
 395                       Ring
 396                     </p>
 397                   </td>
 398 <td>
 399                     <p>
 400                       <span class="inlinemediaobject"><img src="../../../../img/ok.png" alt="ok"></span>
 401                     </p>
 402                   </td>
 403 <td>
 404                     <p>
 405                       <span class="inlinemediaobject"><img src="../../../../img/nyi.png" alt="nyi"></span>
 406                     </p>
 407                   </td>
 408 </tr>
 409 <tr>
 410 <td>
 411                     <p>
 412                       Polygon
 413                     </p>
 414                   </td>
 415 <td>
 416                     <p>
 417                       <span class="inlinemediaobject"><img src="../../../../img/ok.png" alt="ok"></span>
 418                     </p>
 419                   </td>
 420 <td>
 421                     <p>
 422                       <span class="inlinemediaobject"><img src="../../../../img/nyi.png" alt="nyi"></span>
 423                     </p>
 424                   </td>
 425 </tr>
 426 <tr>
 427 <td>
 428                     <p>
 429                       MultiPoint
 430                     </p>
 431                   </td>
 432 <td>
 433                     <p>
 434                       <span class="inlinemediaobject"><img src="../../../../img/ok.png" alt="ok"></span>
 435                     </p>
 436                   </td>
 437 <td>
 438                     <p>
 439                       <span class="inlinemediaobject"><img src="../../../../img/ok.png" alt="ok"></span>
 440                     </p>
 441                   </td>
 442 </tr>
 443 <tr>
 444 <td>
 445                     <p>
 446                       MultiLinestring
 447                     </p>
 448                   </td>
 449 <td>
 450                     <p>
 451                       <span class="inlinemediaobject"><img src="../../../../img/ok.png" alt="ok"></span>
 452                     </p>
 453                   </td>
 454 <td>
 455                     <p>
 456                       <span class="inlinemediaobject"><img src="../../../../img/nyi.png" alt="nyi"></span>
 457                     </p>
 458                   </td>
 459 </tr>
 460 <tr>
 461 <td>
 462                     <p>
 463                       MultiPolygon
 464                     </p>
 465                   </td>
 466 <td>
 467                     <p>
 468                       <span class="inlinemediaobject"><img src="../../../../img/ok.png" alt="ok"></span>
 469                     </p>
 470                   </td>
 471 <td>
 472                     <p>
 473                       <span class="inlinemediaobject"><img src="../../../../img/nyi.png" alt="nyi"></span>
 474                     </p>
 475                   </td>
 476 </tr>
 477 </tbody>
 478 </table></div>
 479 <h6>
 480 <a name="geometry.reference.algorithms.centroid.return_centroid_2_with_strategy.h8"></a>
 481             <span class="phrase"><a name="geometry.reference.algorithms.centroid.return_centroid_2_with_strategy.complexity"></a></span><a class="link" href="return_centroid_2_with_strategy.html#geometry.reference.algorithms.centroid.return_centroid_2_with_strategy.complexity">Complexity</a>
 482           </h6>
 483 <p>
 484             Linear
 485           </p>
 486 <h6>
 487 <a name="geometry.reference.algorithms.centroid.return_centroid_2_with_strategy.h9"></a>
 488             <span class="phrase"><a name="geometry.reference.algorithms.centroid.return_centroid_2_with_strategy.available_strategies"></a></span><a class="link" href="return_centroid_2_with_strategy.html#geometry.reference.algorithms.centroid.return_centroid_2_with_strategy.available_strategies">Available
 489             Strategies</a>
 490           </h6>
 491 <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem">
 492                 <a class="link" href="../../strategies/strategy_centroid_bashein_detmer.html" title="strategy::centroid::bashein_detmer">Bashein
 493                 Detmer (cartesian)</a>
 494               </li></ul></div>
 495 </div>
 496 <table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
 497 <td align="left"></td>
 498 <td align="right"><div class="copyright-footer">Copyright &#169; 2009-2019 Barend Gehrels, Bruno Lalande, Mateusz Loskot, Adam
 499       Wulkiewicz, Oracle and/or its affiliates<p>
 500         Distributed under the Boost Software License, Version 1.0. (See accompanying
 501         file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)
 502       </p>
 503 </div></td>
 504 </tr></table>
 505 <hr>
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