1<html> 2<head> 3<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 4<title>union_</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="../union_.html" title="union_"> 9<link rel="prev" href="union__4_with_strategy.html" title="union_ (with strategy)"> 10<link rel="next" href="../unique.html" title="unique"> 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="union__4_with_strategy.html"><img src="../../../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../union_.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="../unique.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.union_.union__3"></a><a class="link" href="union__3.html" title="union_">union_</a> 28</h5></div></div></div> 29<p> 30 <a class="indexterm" name="idm45635687450704"></a> 31Combines two geometries which each other. 32 </p> 33<h6> 34<a name="geometry.reference.algorithms.union_.union__3.h0"></a> 35 <span class="phrase"><a name="geometry.reference.algorithms.union_.union__3.description"></a></span><a class="link" href="union__3.html#geometry.reference.algorithms.union_.union__3.description">Description</a> 36 </h6> 37<p> 38 The free function union calculates the spatial set theoretic union of 39 two geometries. 40 </p> 41<h6> 42<a name="geometry.reference.algorithms.union_.union__3.h1"></a> 43 <span class="phrase"><a name="geometry.reference.algorithms.union_.union__3.synopsis"></a></span><a class="link" href="union__3.html#geometry.reference.algorithms.union_.union__3.synopsis">Synopsis</a> 44 </h6> 45<p> 46</p> 47<pre class="programlisting"><span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> <span class="identifier">Geometry1</span><span class="special">,</span> <span class="keyword">typename</span> <span class="identifier">Geometry2</span><span class="special">,</span> <span class="keyword">typename</span> <span class="identifier">Collection</span><span class="special">></span> 48<span class="keyword">void</span> <span class="identifier">union_</span><span class="special">(</span><span class="identifier">Geometry1</span> <span class="keyword">const</span> <span class="special">&</span> <span class="identifier">geometry1</span><span class="special">,</span> <span class="identifier">Geometry2</span> <span class="keyword">const</span> <span class="special">&</span> <span class="identifier">geometry2</span><span class="special">,</span> <span class="identifier">Collection</span> <span class="special">&</span> <span class="identifier">output_collection</span><span class="special">)</span></pre> 49<p> 50 </p> 51<h6> 52<a name="geometry.reference.algorithms.union_.union__3.h2"></a> 53 <span class="phrase"><a name="geometry.reference.algorithms.union_.union__3.parameters"></a></span><a class="link" href="union__3.html#geometry.reference.algorithms.union_.union__3.parameters">Parameters</a> 54 </h6> 55<div class="informaltable"><table class="table"> 56<colgroup> 57<col> 58<col> 59<col> 60<col> 61</colgroup> 62<thead><tr> 63<th> 64 <p> 65 Type 66 </p> 67 </th> 68<th> 69 <p> 70 Concept 71 </p> 72 </th> 73<th> 74 <p> 75 Name 76 </p> 77 </th> 78<th> 79 <p> 80 Description 81 </p> 82 </th> 83</tr></thead> 84<tbody> 85<tr> 86<td> 87 <p> 88 Geometry1 const & 89 </p> 90 </td> 91<td> 92 <p> 93 Any type fulfilling a Geometry Concept 94 </p> 95 </td> 96<td> 97 <p> 98 geometry1 99 </p> 100 </td> 101<td> 102 <p> 103 A model of the specified concept 104 </p> 105 </td> 106</tr> 107<tr> 108<td> 109 <p> 110 Geometry2 const & 111 </p> 112 </td> 113<td> 114 <p> 115 Any type fulfilling a Geometry Concept 116 </p> 117 </td> 118<td> 119 <p> 120 geometry2 121 </p> 122 </td> 123<td> 124 <p> 125 A model of the specified concept 126 </p> 127 </td> 128</tr> 129<tr> 130<td> 131 <p> 132 Collection & 133 </p> 134 </td> 135<td> 136 <p> 137 output collection, either a multi-geometry, or a std::vector<Geometry> 138 / std::deque<Geometry> etc 139 </p> 140 </td> 141<td> 142 <p> 143 output_collection 144 </p> 145 </td> 146<td> 147 <p> 148 the output collection 149 </p> 150 </td> 151</tr> 152</tbody> 153</table></div> 154<h6> 155<a name="geometry.reference.algorithms.union_.union__3.h3"></a> 156 <span class="phrase"><a name="geometry.reference.algorithms.union_.union__3.header"></a></span><a class="link" href="union__3.html#geometry.reference.algorithms.union_.union__3.header">Header</a> 157 </h6> 158<p> 159 Either 160 </p> 161<p> 162 <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> 163 </p> 164<p> 165 Or 166 </p> 167<p> 168 <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="keyword">union</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span></code> 169 </p> 170<h6> 171<a name="geometry.reference.algorithms.union_.union__3.h4"></a> 172 <span class="phrase"><a name="geometry.reference.algorithms.union_.union__3.conformance"></a></span><a class="link" href="union__3.html#geometry.reference.algorithms.union_.union__3.conformance">Conformance</a> 173 </h6> 174<p> 175 The function union implements function Union from the <a href="http://www.opengeospatial.org/standards/sfa" target="_top">OGC 176 Simple Feature Specification</a>. 177 </p> 178<div class="note"><table border="0" summary="Note"> 179<tr> 180<td rowspan="2" align="center" valign="top" width="25"><img alt="[Note]" src="../../../../../../../../doc/src/images/note.png"></td> 181<th align="left">Note</th> 182</tr> 183<tr><td align="left" valign="top"><p> 184 Boost.Geometry adds an underscore to avoid using the <code class="computeroutput"><span class="keyword">union</span></code> keyword 185 </p></td></tr> 186</table></div> 187<h6> 188<a name="geometry.reference.algorithms.union_.union__3.h5"></a> 189 <span class="phrase"><a name="geometry.reference.algorithms.union_.union__3.behavior"></a></span><a class="link" href="union__3.html#geometry.reference.algorithms.union_.union__3.behavior">Behavior</a> 190 </h6> 191<div class="informaltable"><table class="table"> 192<colgroup> 193<col> 194<col> 195</colgroup> 196<thead><tr> 197<th> 198 <p> 199 Case 200 </p> 201 </th> 202<th> 203 <p> 204 Behavior 205 </p> 206 </th> 207</tr></thead> 208<tbody> 209<tr> 210<td> 211 <p> 212 GeometryOut is a Point 213 </p> 214 </td> 215<td> 216 <p> 217 Calculates union linestrings of input (multi)points 218 </p> 219 </td> 220</tr> 221<tr> 222<td> 223 <p> 224 GeometryOut is a Linestring 225 </p> 226 </td> 227<td> 228 <p> 229 Calculates union linestrings of input (multi)linestrings 230 </p> 231 </td> 232</tr> 233<tr> 234<td> 235 <p> 236 GeometryOut is a Polygon 237 </p> 238 </td> 239<td> 240 <p> 241 Calculates union polygons of input (multi)polygons and/or boxes 242 </p> 243 </td> 244</tr> 245</tbody> 246</table></div> 247<div class="note"><table border="0" summary="Note"> 248<tr> 249<td rowspan="2" align="center" valign="top" width="25"><img alt="[Note]" src="../../../../../../../../doc/src/images/note.png"></td> 250<th align="left">Note</th> 251</tr> 252<tr><td align="left" valign="top"><p> 253 Check the <a class="link" href="../../concepts/concept_polygon.html" title="Polygon Concept">Polygon 254 Concept</a> for the rules that polygon input for this algorithm 255 should fulfill 256 </p></td></tr> 257</table></div> 258<h6> 259<a name="geometry.reference.algorithms.union_.union__3.h6"></a> 260 <span class="phrase"><a name="geometry.reference.algorithms.union_.union__3.example"></a></span><a class="link" href="union__3.html#geometry.reference.algorithms.union_.union__3.example">Example</a> 261 </h6> 262<p> 263 Shows how to get a united geometry of two polygons 264 </p> 265<p> 266</p> 267<pre class="programlisting"><span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">iostream</span><span class="special">></span> 268<span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">vector</span><span class="special">></span> 269 270<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> 271<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">geometries</span><span class="special">/</span><span class="identifier">point_xy</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> 272<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">geometries</span><span class="special">/</span><span class="identifier">polygon</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> 273 274<span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">foreach</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> 275 276 277<span class="keyword">int</span> <span class="identifier">main</span><span class="special">()</span> 278<span class="special">{</span> 279 <span class="keyword">typedef</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">geometry</span><span class="special">::</span><span class="identifier">model</span><span class="special">::</span><span class="identifier">polygon</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">model</span><span class="special">::</span><span class="identifier">d2</span><span class="special">::</span><span class="identifier">point_xy</span><span class="special"><</span><span class="keyword">double</span><span class="special">></span> <span class="special">></span> <span class="identifier">polygon</span><span class="special">;</span> 280 281 <span class="identifier">polygon</span> <span class="identifier">green</span><span class="special">,</span> <span class="identifier">blue</span><span class="special">;</span> 282 283 <span class="identifier">boost</span><span class="special">::</span><span class="identifier">geometry</span><span class="special">::</span><span class="identifier">read_wkt</span><span class="special">(</span> 284 <span class="string">"POLYGON((2 1.3,2.4 1.7,2.8 1.8,3.4 1.2,3.7 1.6,3.4 2,4.1 3,5.3 2.6,5.4 1.2,4.9 0.8,2.9 0.7,2 1.3)"</span> 285 <span class="string">"(4.0 2.0, 4.2 1.4, 4.8 1.9, 4.4 2.2, 4.0 2.0))"</span><span class="special">,</span> <span class="identifier">green</span><span class="special">);</span> 286 287 <span class="identifier">boost</span><span class="special">::</span><span class="identifier">geometry</span><span class="special">::</span><span class="identifier">read_wkt</span><span class="special">(</span> 288 <span class="string">"POLYGON((4.0 -0.5 , 3.5 1.0 , 2.0 1.5 , 3.5 2.0 , 4.0 3.5 , 4.5 2.0 , 6.0 1.5 , 4.5 1.0 , 4.0 -0.5))"</span><span class="special">,</span> <span class="identifier">blue</span><span class="special">);</span> 289 290 <span class="identifier">std</span><span class="special">::</span><span class="identifier">vector</span><span class="special"><</span><span class="identifier">polygon</span><span class="special">></span> <span class="identifier">output</span><span class="special">;</span> 291 <span class="identifier">boost</span><span class="special">::</span><span class="identifier">geometry</span><span class="special">::</span><span class="identifier">union_</span><span class="special">(</span><span class="identifier">green</span><span class="special">,</span> <span class="identifier">blue</span><span class="special">,</span> <span class="identifier">output</span><span class="special">);</span> 292 293 <span class="keyword">int</span> <span class="identifier">i</span> <span class="special">=</span> <span class="number">0</span><span class="special">;</span> 294 <span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special"><<</span> <span class="string">"green || blue:"</span> <span class="special"><<</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">endl</span><span class="special">;</span> 295 <span class="identifier">BOOST_FOREACH</span><span class="special">(</span><span class="identifier">polygon</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">p</span><span class="special">,</span> <span class="identifier">output</span><span class="special">)</span> 296 <span class="special">{</span> 297 <span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special"><<</span> <span class="identifier">i</span><span class="special">++</span> <span class="special"><<</span> <span class="string">": "</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">area</span><span class="special">(</span><span class="identifier">p</span><span class="special">)</span> <span class="special"><<</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">endl</span><span class="special">;</span> 298 <span class="special">}</span> 299 300 301 <span class="keyword">return</span> <span class="number">0</span><span class="special">;</span> 302<span class="special">}</span> 303</pre> 304<p> 305 </p> 306<p> 307 Output: 308 </p> 309<pre class="programlisting">green || blue: 3100: 5.64795 311 312<img src="../../../../img/algorithms/union.png" alt="union"> 313 314</pre> 315<h6> 316<a name="geometry.reference.algorithms.union_.union__3.h7"></a> 317 <span class="phrase"><a name="geometry.reference.algorithms.union_.union__3.see_also"></a></span><a class="link" href="union__3.html#geometry.reference.algorithms.union_.union__3.see_also">See 318 also</a> 319 </h6> 320<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "> 321<li class="listitem"> 322 <a class="link" href="../intersection.html" title="intersection">intersection</a> 323 </li> 324<li class="listitem"> 325 <a class="link" href="../difference.html" title="difference">difference</a> 326 </li> 327<li class="listitem"> 328 <a class="link" href="../sym_difference.html" title="sym_difference">sym_difference 329 (symmetric difference)</a> 330 </li> 331</ul></div> 332</div> 333<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> 334<td align="left"></td> 335<td align="right"><div class="copyright-footer">Copyright © 2009-2019 Barend Gehrels, Bruno Lalande, Mateusz Loskot, Adam 336 Wulkiewicz, Oracle and/or its affiliates<p> 337 Distributed under the Boost Software License, Version 1.0. (See accompanying 338 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>) 339 </p> 340</div></td> 341</tr></table> 342<hr> 343<div class="spirit-nav"> 344<a accesskey="p" href="union__4_with_strategy.html"><img src="../../../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../union_.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="../unique.html"><img src="../../../../../../../../doc/src/images/next.png" alt="Next"></a> 345</div> 346</body> 347</html> 348
