1<html> 2<head> 3<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 4<title>centroid (with strategy)</title> 5<link rel="stylesheet" href="../../../../../../../../doc/src/boostbook.css" type="text/css"> 6<meta name="generator" content="DocBook XSL Stylesheets V1.79.1"> 7<link rel="home" href="../../../../index.html" title="Chapter 1. Geometry"> 8<link rel="up" href="../centroid.html" title="centroid"> 9<link rel="prev" href="../centroid.html" title="centroid"> 10<link rel="next" href="centroid_2.html" title="centroid"> 11</head> 12<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"> 13<table cellpadding="2" width="100%"><tr> 14<td valign="top"><img alt="Boost C++ Libraries" width="277" height="86" src="../../../../../../../../boost.png"></td> 15<td align="center"><a href="../../../../../../../../index.html">Home</a></td> 16<td align="center"><a href="../../../../../../../../libs/libraries.htm">Libraries</a></td> 17<td align="center"><a href="http://www.boost.org/users/people.html">People</a></td> 18<td align="center"><a href="http://www.boost.org/users/faq.html">FAQ</a></td> 19<td align="center"><a href="../../../../../../../../more/index.htm">More</a></td> 20</tr></table> 21<hr> 22<div class="spirit-nav"> 23<a accesskey="p" href="../centroid.html"><img src="../../../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../centroid.html"><img src="../../../../../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../../../../index.html"><img src="../../../../../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="centroid_2.html"><img src="../../../../../../../../doc/src/images/next.png" alt="Next"></a> 24</div> 25<div class="section"> 26<div class="titlepage"><div><div><h5 class="title"> 27<a name="geometry.reference.algorithms.centroid.centroid_3_with_strategy"></a><a class="link" href="centroid_3_with_strategy.html" title="centroid (with strategy)">centroid 28 (with strategy)</a> 29</h5></div></div></div> 30<p> 31 <a class="indexterm" name="idm45635705813648"></a> 32Calculates the centroid of a geometry using the specified strategy. 33 </p> 34<h6> 35<a name="geometry.reference.algorithms.centroid.centroid_3_with_strategy.h0"></a> 36 <span class="phrase"><a name="geometry.reference.algorithms.centroid.centroid_3_with_strategy.description"></a></span><a class="link" href="centroid_3_with_strategy.html#geometry.reference.algorithms.centroid.centroid_3_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. Reasons to specify a strategy include: use another 41 coordinate system for calculations; construct the strategy beforehand 42 (e.g. with the radius of the Earth); select a strategy when there are 43 more than one available for a calculation. 44 </p> 45<h6> 46<a name="geometry.reference.algorithms.centroid.centroid_3_with_strategy.h1"></a> 47 <span class="phrase"><a name="geometry.reference.algorithms.centroid.centroid_3_with_strategy.synopsis"></a></span><a class="link" href="centroid_3_with_strategy.html#geometry.reference.algorithms.centroid.centroid_3_with_strategy.synopsis">Synopsis</a> 48 </h6> 49<p> 50</p> 51<pre class="programlisting"><span class="keyword">template</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">Point</span><span class="special">,</span> <span class="keyword">typename</span> <span class="identifier">Strategy</span><span class="special">></span> 52<span class="keyword">void</span> <span class="identifier">centroid</span><span class="special">(</span><span class="identifier">Geometry</span> <span class="keyword">const</span> <span class="special">&</span> <span class="identifier">geometry</span><span class="special">,</span> <span class="identifier">Point</span> <span class="special">&</span> <span class="identifier">c</span><span class="special">,</span> <span class="identifier">Strategy</span> <span class="keyword">const</span> <span class="special">&</span> <span class="identifier">strategy</span><span class="special">)</span></pre> 53<p> 54 </p> 55<h6> 56<a name="geometry.reference.algorithms.centroid.centroid_3_with_strategy.h2"></a> 57 <span class="phrase"><a name="geometry.reference.algorithms.centroid.centroid_3_with_strategy.parameters"></a></span><a class="link" href="centroid_3_with_strategy.html#geometry.reference.algorithms.centroid.centroid_3_with_strategy.parameters">Parameters</a> 58 </h6> 59<div class="informaltable"><table class="table"> 60<colgroup> 61<col> 62<col> 63<col> 64<col> 65</colgroup> 66<thead><tr> 67<th> 68 <p> 69 Type 70 </p> 71 </th> 72<th> 73 <p> 74 Concept 75 </p> 76 </th> 77<th> 78 <p> 79 Name 80 </p> 81 </th> 82<th> 83 <p> 84 Description 85 </p> 86 </th> 87</tr></thead> 88<tbody> 89<tr> 90<td> 91 <p> 92 Geometry const & 93 </p> 94 </td> 95<td> 96 <p> 97 Any type fulfilling a Geometry Concept 98 </p> 99 </td> 100<td> 101 <p> 102 geometry 103 </p> 104 </td> 105<td> 106 <p> 107 A model of the specified concept 108 </p> 109 </td> 110</tr> 111<tr> 112<td> 113 <p> 114 Point & 115 </p> 116 </td> 117<td> 118 <p> 119 Any type fulfilling a Point Concept 120 </p> 121 </td> 122<td> 123 <p> 124 c 125 </p> 126 </td> 127<td> 128 <p> 129 A model of the specified Point Concept which is set to the 130 centroid 131 </p> 132 </td> 133</tr> 134<tr> 135<td> 136 <p> 137 Strategy const & 138 </p> 139 </td> 140<td> 141 <p> 142 Any type fulfilling a Centroid Strategy Concept 143 </p> 144 </td> 145<td> 146 <p> 147 strategy 148 </p> 149 </td> 150<td> 151 <p> 152 The strategy which will be used for centroid calculations 153 </p> 154 </td> 155</tr> 156</tbody> 157</table></div> 158<h6> 159<a name="geometry.reference.algorithms.centroid.centroid_3_with_strategy.h3"></a> 160 <span class="phrase"><a name="geometry.reference.algorithms.centroid.centroid_3_with_strategy.header"></a></span><a class="link" href="centroid_3_with_strategy.html#geometry.reference.algorithms.centroid.centroid_3_with_strategy.header">Header</a> 161 </h6> 162<p> 163 Either 164 </p> 165<p> 166 <code class="computeroutput"><span class="preprocessor">#include</span> <span class="special"><</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">></span></code> 167 </p> 168<p> 169 Or 170 </p> 171<p> 172 <code class="computeroutput"><span class="preprocessor">#include</span> <span class="special"><</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">></span></code> 173 </p> 174<h6> 175<a name="geometry.reference.algorithms.centroid.centroid_3_with_strategy.h4"></a> 176 <span class="phrase"><a name="geometry.reference.algorithms.centroid.centroid_3_with_strategy.conformance"></a></span><a class="link" href="centroid_3_with_strategy.html#geometry.reference.algorithms.centroid.centroid_3_with_strategy.conformance">Conformance</a> 177 </h6> 178<p> 179 The function centroid implements function Centroid from the <a href="http://www.opengeospatial.org/standards/sfa" target="_top">OGC 180 Simple Feature Specification</a>. 181 </p> 182<h6> 183<a name="geometry.reference.algorithms.centroid.centroid_3_with_strategy.h5"></a> 184 <span class="phrase"><a name="geometry.reference.algorithms.centroid.centroid_3_with_strategy.behavior"></a></span><a class="link" href="centroid_3_with_strategy.html#geometry.reference.algorithms.centroid.centroid_3_with_strategy.behavior">Behavior</a> 185 </h6> 186<div class="informaltable"><table class="table"> 187<colgroup> 188<col> 189<col> 190</colgroup> 191<thead><tr> 192<th> 193 <p> 194 Case 195 </p> 196 </th> 197<th> 198 <p> 199 Behavior 200 </p> 201 </th> 202</tr></thead> 203<tbody> 204<tr> 205<td> 206 <p> 207 Point 208 </p> 209 </td> 210<td> 211 <p> 212 Returns the point itself as the centroid 213 </p> 214 </td> 215</tr> 216<tr> 217<td> 218 <p> 219 Multi Point 220 </p> 221 </td> 222<td> 223 <p> 224 Calculates centroid (based on average) 225 </p> 226 </td> 227</tr> 228<tr> 229<td> 230 <p> 231 linear (e.g. linestring) 232 </p> 233 </td> 234<td> 235 <p> 236 Calculates centroid (based on weighted length) 237 </p> 238 </td> 239</tr> 240<tr> 241<td> 242 <p> 243 areal (e.g. polygon) 244 </p> 245 </td> 246<td> 247 <p> 248 Calculates centroid 249 </p> 250 </td> 251</tr> 252<tr> 253<td> 254 <p> 255 Empty (e.g. polygon without points) 256 </p> 257 </td> 258<td> 259 <p> 260 Throws a <a class="link" href="../../exceptions/centroid_exception.html" title="centroid_exception">centroid_exception</a> 261 </p> 262 </td> 263</tr> 264<tr> 265<td> 266 <p> 267 Cartesian 268 </p> 269 </td> 270<td> 271 <p> 272 Implemented 273 </p> 274 </td> 275</tr> 276<tr> 277<td> 278 <p> 279 Spherical 280 </p> 281 </td> 282<td> 283 <p> 284 Calculates the centroid as if based on Cartesian coordinates 285 </p> 286 </td> 287</tr> 288</tbody> 289</table></div> 290<h6> 291<a name="geometry.reference.algorithms.centroid.centroid_3_with_strategy.h6"></a> 292 <span class="phrase"><a name="geometry.reference.algorithms.centroid.centroid_3_with_strategy.supported_geometries"></a></span><a class="link" href="centroid_3_with_strategy.html#geometry.reference.algorithms.centroid.centroid_3_with_strategy.supported_geometries">Supported 293 geometries</a> 294 </h6> 295<div class="informaltable"><table class="table"> 296<colgroup> 297<col> 298<col> 299<col> 300</colgroup> 301<thead><tr> 302<th> 303 </th> 304<th> 305 <p> 306 2D 307 </p> 308 </th> 309<th> 310 <p> 311 3D 312 </p> 313 </th> 314</tr></thead> 315<tbody> 316<tr> 317<td> 318 <p> 319 Point 320 </p> 321 </td> 322<td> 323 <p> 324 <span class="inlinemediaobject"><img src="../../../../img/ok.png" alt="ok"></span> 325 </p> 326 </td> 327<td> 328 <p> 329 <span class="inlinemediaobject"><img src="../../../../img/ok.png" alt="ok"></span> 330 </p> 331 </td> 332</tr> 333<tr> 334<td> 335 <p> 336 Segment 337 </p> 338 </td> 339<td> 340 <p> 341 <span class="inlinemediaobject"><img src="../../../../img/ok.png" alt="ok"></span> 342 </p> 343 </td> 344<td> 345 <p> 346 <span class="inlinemediaobject"><img src="../../../../img/ok.png" alt="ok"></span> 347 </p> 348 </td> 349</tr> 350<tr> 351<td> 352 <p> 353 Box 354 </p> 355 </td> 356<td> 357 <p> 358 <span class="inlinemediaobject"><img src="../../../../img/ok.png" alt="ok"></span> 359 </p> 360 </td> 361<td> 362 <p> 363 <span class="inlinemediaobject"><img src="../../../../img/ok.png" alt="ok"></span> 364 </p> 365 </td> 366</tr> 367<tr> 368<td> 369 <p> 370 Linestring 371 </p> 372 </td> 373<td> 374 <p> 375 <span class="inlinemediaobject"><img src="../../../../img/ok.png" alt="ok"></span> 376 </p> 377 </td> 378<td> 379 <p> 380 <span class="inlinemediaobject"><img src="../../../../img/nyi.png" alt="nyi"></span> 381 </p> 382 </td> 383</tr> 384<tr> 385<td> 386 <p> 387 Ring 388 </p> 389 </td> 390<td> 391 <p> 392 <span class="inlinemediaobject"><img src="../../../../img/ok.png" alt="ok"></span> 393 </p> 394 </td> 395<td> 396 <p> 397 <span class="inlinemediaobject"><img src="../../../../img/nyi.png" alt="nyi"></span> 398 </p> 399 </td> 400</tr> 401<tr> 402<td> 403 <p> 404 Polygon 405 </p> 406 </td> 407<td> 408 <p> 409 <span class="inlinemediaobject"><img src="../../../../img/ok.png" alt="ok"></span> 410 </p> 411 </td> 412<td> 413 <p> 414 <span class="inlinemediaobject"><img src="../../../../img/nyi.png" alt="nyi"></span> 415 </p> 416 </td> 417</tr> 418<tr> 419<td> 420 <p> 421 MultiPoint 422 </p> 423 </td> 424<td> 425 <p> 426 <span class="inlinemediaobject"><img src="../../../../img/ok.png" alt="ok"></span> 427 </p> 428 </td> 429<td> 430 <p> 431 <span class="inlinemediaobject"><img src="../../../../img/ok.png" alt="ok"></span> 432 </p> 433 </td> 434</tr> 435<tr> 436<td> 437 <p> 438 MultiLinestring 439 </p> 440 </td> 441<td> 442 <p> 443 <span class="inlinemediaobject"><img src="../../../../img/ok.png" alt="ok"></span> 444 </p> 445 </td> 446<td> 447 <p> 448 <span class="inlinemediaobject"><img src="../../../../img/nyi.png" alt="nyi"></span> 449 </p> 450 </td> 451</tr> 452<tr> 453<td> 454 <p> 455 MultiPolygon 456 </p> 457 </td> 458<td> 459 <p> 460 <span class="inlinemediaobject"><img src="../../../../img/ok.png" alt="ok"></span> 461 </p> 462 </td> 463<td> 464 <p> 465 <span class="inlinemediaobject"><img src="../../../../img/nyi.png" alt="nyi"></span> 466 </p> 467 </td> 468</tr> 469</tbody> 470</table></div> 471<h6> 472<a name="geometry.reference.algorithms.centroid.centroid_3_with_strategy.h7"></a> 473 <span class="phrase"><a name="geometry.reference.algorithms.centroid.centroid_3_with_strategy.complexity"></a></span><a class="link" href="centroid_3_with_strategy.html#geometry.reference.algorithms.centroid.centroid_3_with_strategy.complexity">Complexity</a> 474 </h6> 475<p> 476 Linear 477 </p> 478<h6> 479<a name="geometry.reference.algorithms.centroid.centroid_3_with_strategy.h8"></a> 480 <span class="phrase"><a name="geometry.reference.algorithms.centroid.centroid_3_with_strategy.available_strategies"></a></span><a class="link" href="centroid_3_with_strategy.html#geometry.reference.algorithms.centroid.centroid_3_with_strategy.available_strategies">Available 481 Strategies</a> 482 </h6> 483<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"> 484 <a class="link" href="../../strategies/strategy_centroid_bashein_detmer.html" title="strategy::centroid::bashein_detmer">Bashein 485 Detmer (cartesian)</a> 486 </li></ul></div> 487</div> 488<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> 489<td align="left"></td> 490<td align="right"><div class="copyright-footer">Copyright © 2009-2019 Barend Gehrels, Bruno Lalande, Mateusz Loskot, Adam 491 Wulkiewicz, Oracle and/or its affiliates<p> 492 Distributed under the Boost Software License, Version 1.0. (See accompanying 493 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>) 494 </p> 495</div></td> 496</tr></table> 497<hr> 498<div class="spirit-nav"> 499<a accesskey="p" href="../centroid.html"><img src="../../../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../centroid.html"><img src="../../../../../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../../../../index.html"><img src="../../../../../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="centroid_2.html"><img src="../../../../../../../../doc/src/images/next.png" alt="Next"></a> 500</div> 501</body> 502</html> 503
