1<html> 2<head> 3<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 4<title>difference</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="../difference.html" title="difference"> 9<link rel="prev" href="difference_4_with_strategy.html" title="difference (with strategy)"> 10<link rel="next" href="../discrete_frechet_distance.html" title="discrete_frechet_distance"> 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="difference_4_with_strategy.html"><img src="../../../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../difference.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="../discrete_frechet_distance.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.difference.difference_3"></a><a class="link" href="difference_3.html" title="difference">difference</a> 28</h5></div></div></div> 29<p> 30 <a class="indexterm" name="idm45635701356752"></a> 31 </p> 32<h6> 33<a name="geometry.reference.algorithms.difference.difference_3.h0"></a> 34 <span class="phrase"><a name="geometry.reference.algorithms.difference.difference_3.description"></a></span><a class="link" href="difference_3.html#geometry.reference.algorithms.difference.difference_3.description">Description</a> 35 </h6> 36<p> 37 Calculate the difference of two geometries 38 </p> 39<p> 40 The free function difference calculates the spatial set theoretic difference 41 of two geometries. 42 </p> 43<h6> 44<a name="geometry.reference.algorithms.difference.difference_3.h1"></a> 45 <span class="phrase"><a name="geometry.reference.algorithms.difference.difference_3.synopsis"></a></span><a class="link" href="difference_3.html#geometry.reference.algorithms.difference.difference_3.synopsis">Synopsis</a> 46 </h6> 47<p> 48</p> 49<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> 50<span class="keyword">void</span> <span class="identifier">difference</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> 51<p> 52 </p> 53<h6> 54<a name="geometry.reference.algorithms.difference.difference_3.h2"></a> 55 <span class="phrase"><a name="geometry.reference.algorithms.difference.difference_3.parameters"></a></span><a class="link" href="difference_3.html#geometry.reference.algorithms.difference.difference_3.parameters">Parameters</a> 56 </h6> 57<div class="informaltable"><table class="table"> 58<colgroup> 59<col> 60<col> 61<col> 62<col> 63</colgroup> 64<thead><tr> 65<th> 66 <p> 67 Type 68 </p> 69 </th> 70<th> 71 <p> 72 Concept 73 </p> 74 </th> 75<th> 76 <p> 77 Name 78 </p> 79 </th> 80<th> 81 <p> 82 Description 83 </p> 84 </th> 85</tr></thead> 86<tbody> 87<tr> 88<td> 89 <p> 90 Geometry1 const & 91 </p> 92 </td> 93<td> 94 <p> 95 Any type fulfilling a Geometry Concept 96 </p> 97 </td> 98<td> 99 <p> 100 geometry1 101 </p> 102 </td> 103<td> 104 <p> 105 A model of the specified concept 106 </p> 107 </td> 108</tr> 109<tr> 110<td> 111 <p> 112 Geometry2 const & 113 </p> 114 </td> 115<td> 116 <p> 117 Any type fulfilling a Geometry Concept 118 </p> 119 </td> 120<td> 121 <p> 122 geometry2 123 </p> 124 </td> 125<td> 126 <p> 127 A model of the specified concept 128 </p> 129 </td> 130</tr> 131<tr> 132<td> 133 <p> 134 Collection & 135 </p> 136 </td> 137<td> 138 <p> 139 output collection, either a multi-geometry, or a std::vector<Geometry> 140 / std::deque<Geometry> etc 141 </p> 142 </td> 143<td> 144 <p> 145 output_collection 146 </p> 147 </td> 148<td> 149 <p> 150 the output collection 151 </p> 152 </td> 153</tr> 154</tbody> 155</table></div> 156<h6> 157<a name="geometry.reference.algorithms.difference.difference_3.h3"></a> 158 <span class="phrase"><a name="geometry.reference.algorithms.difference.difference_3.header"></a></span><a class="link" href="difference_3.html#geometry.reference.algorithms.difference.difference_3.header">Header</a> 159 </h6> 160<p> 161 Either 162 </p> 163<p> 164 <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> 165 </p> 166<p> 167 Or 168 </p> 169<p> 170 <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">difference</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span></code> 171 </p> 172<h6> 173<a name="geometry.reference.algorithms.difference.difference_3.h4"></a> 174 <span class="phrase"><a name="geometry.reference.algorithms.difference.difference_3.conformance"></a></span><a class="link" href="difference_3.html#geometry.reference.algorithms.difference.difference_3.conformance">Conformance</a> 175 </h6> 176<p> 177 The function difference implements function Difference from the <a href="http://www.opengeospatial.org/standards/sfa" target="_top">OGC Simple Feature 178 Specification</a>. 179 </p> 180<h6> 181<a name="geometry.reference.algorithms.difference.difference_3.h5"></a> 182 <span class="phrase"><a name="geometry.reference.algorithms.difference.difference_3.behavior"></a></span><a class="link" href="difference_3.html#geometry.reference.algorithms.difference.difference_3.behavior">Behavior</a> 183 </h6> 184<div class="informaltable"><table class="table"> 185<colgroup> 186<col> 187<col> 188</colgroup> 189<thead><tr> 190<th> 191 <p> 192 Case 193 </p> 194 </th> 195<th> 196 <p> 197 Behavior 198 </p> 199 </th> 200</tr></thead> 201<tbody> 202<tr> 203<td> 204 <p> 205 areal (e.g. polygon) 206 </p> 207 </td> 208<td> 209 <p> 210 All combinations of: box, ring, polygon, multi_polygon 211 </p> 212 </td> 213</tr> 214<tr> 215<td> 216 <p> 217 linear (e.g. linestring) / areal (e.g. polygon) 218 </p> 219 </td> 220<td> 221 <p> 222 A combinations of a (multi) linestring with a (multi) polygon 223 results in a collection of linestrings 224 </p> 225 </td> 226</tr> 227<tr> 228<td> 229 <p> 230 linear (e.g. linestring) 231 </p> 232 </td> 233<td> 234 <p> 235 All combinations of: linestring, multi_linestring; results 236 in a collection of linestrings 237 </p> 238 </td> 239</tr> 240<tr> 241<td> 242 <p> 243 pointlike (e.g. point) 244 </p> 245 </td> 246<td> 247 <p> 248 All combinations of: point, multi_point; results in a collection 249 of points 250 </p> 251 </td> 252</tr> 253<tr> 254<td> 255 <p> 256 Other geometries 257 </p> 258 </td> 259<td> 260 <p> 261 Not yet supported in this version 262 </p> 263 </td> 264</tr> 265<tr> 266<td> 267 <p> 268 Spherical 269 </p> 270 </td> 271<td> 272 <p> 273 Not yet supported in this version 274 </p> 275 </td> 276</tr> 277<tr> 278<td> 279 <p> 280 Three dimensional 281 </p> 282 </td> 283<td> 284 <p> 285 Not yet supported in this version 286 </p> 287 </td> 288</tr> 289</tbody> 290</table></div> 291<div class="note"><table border="0" summary="Note"> 292<tr> 293<td rowspan="2" align="center" valign="top" width="25"><img alt="[Note]" src="../../../../../../../../doc/src/images/note.png"></td> 294<th align="left">Note</th> 295</tr> 296<tr><td align="left" valign="top"><p> 297 Check the <a class="link" href="../../concepts/concept_polygon.html" title="Polygon Concept">Polygon 298 Concept</a> for the rules that polygon input for this algorithm 299 should fulfill 300 </p></td></tr> 301</table></div> 302<h6> 303<a name="geometry.reference.algorithms.difference.difference_3.h6"></a> 304 <span class="phrase"><a name="geometry.reference.algorithms.difference.difference_3.example"></a></span><a class="link" href="difference_3.html#geometry.reference.algorithms.difference.difference_3.example">Example</a> 305 </h6> 306<p> 307 Shows how to subtract one polygon from another polygon 308 </p> 309<p> 310</p> 311<pre class="programlisting"><span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">iostream</span><span class="special">></span> 312<span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">list</span><span class="special">></span> 313 314<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> 315<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> 316<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> 317 318<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> 319 320 321<span class="keyword">int</span> <span class="identifier">main</span><span class="special">()</span> 322<span class="special">{</span> 323 <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> 324 325 <span class="identifier">polygon</span> <span class="identifier">green</span><span class="special">,</span> <span class="identifier">blue</span><span class="special">;</span> 326 327 <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> 328 <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> 329 <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> 330 331 <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> 332 <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> 333 334 <span class="identifier">std</span><span class="special">::</span><span class="identifier">list</span><span class="special"><</span><span class="identifier">polygon</span><span class="special">></span> <span class="identifier">output</span><span class="special">;</span> 335 <span class="identifier">boost</span><span class="special">::</span><span class="identifier">geometry</span><span class="special">::</span><span class="identifier">difference</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> 336 337 <span class="keyword">int</span> <span class="identifier">i</span> <span class="special">=</span> <span class="number">0</span><span class="special">;</span> 338 <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> 339 <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> 340 <span class="special">{</span> 341 <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> 342 <span class="special">}</span> 343 344 345 <span class="identifier">output</span><span class="special">.</span><span class="identifier">clear</span><span class="special">();</span> 346 <span class="identifier">boost</span><span class="special">::</span><span class="identifier">geometry</span><span class="special">::</span><span class="identifier">difference</span><span class="special">(</span><span class="identifier">blue</span><span class="special">,</span> <span class="identifier">green</span><span class="special">,</span> <span class="identifier">output</span><span class="special">);</span> 347 348 <span class="identifier">i</span> <span class="special">=</span> <span class="number">0</span><span class="special">;</span> 349 <span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special"><<</span> <span class="string">"blue - green:"</span> <span class="special"><<</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">endl</span><span class="special">;</span> 350 <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> 351 <span class="special">{</span> 352 <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> 353 <span class="special">}</span> 354 355 356 <span class="keyword">return</span> <span class="number">0</span><span class="special">;</span> 357<span class="special">}</span> 358</pre> 359<p> 360 </p> 361<p> 362 Output: 363 </p> 364<pre class="programlisting">green - blue: 3650: 0.02375 3661: 0.542951 3672: 0.0149697 3683: 0.226855 3694: 0.839424 370 371<img src="../../../../img/algorithms/difference_a.png" alt="difference_a"> 372 373blue - green: 3740: 0.525154 3751: 0.015 3762: 0.181136 3773: 0.128798 3784: 0.340083 3795: 0.307778 380 381<img src="../../../../img/algorithms/difference_b.png" alt="difference_b"> 382</pre> 383<h6> 384<a name="geometry.reference.algorithms.difference.difference_3.h7"></a> 385 <span class="phrase"><a name="geometry.reference.algorithms.difference.difference_3.see_also"></a></span><a class="link" href="difference_3.html#geometry.reference.algorithms.difference.difference_3.see_also">See 386 also</a> 387 </h6> 388<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "> 389<li class="listitem"> 390 <a class="link" href="../sym_difference.html" title="sym_difference">sym_difference 391 (symmetric difference)</a> 392 </li> 393<li class="listitem"> 394 <a class="link" href="../intersection.html" title="intersection">intersection</a> 395 </li> 396<li class="listitem"> 397 <a class="link" href="../union_.html" title="union_">union</a> 398 </li> 399</ul></div> 400</div> 401<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> 402<td align="left"></td> 403<td align="right"><div class="copyright-footer">Copyright © 2009-2019 Barend Gehrels, Bruno Lalande, Mateusz Loskot, Adam 404 Wulkiewicz, Oracle and/or its affiliates<p> 405 Distributed under the Boost Software License, Version 1.0. (See accompanying 406 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>) 407 </p> 408</div></td> 409</tr></table> 410<hr> 411<div class="spirit-nav"> 412<a accesskey="p" href="difference_4_with_strategy.html"><img src="../../../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../difference.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="../discrete_frechet_distance.html"><img src="../../../../../../../../doc/src/images/next.png" alt="Next"></a> 413</div> 414</body> 415</html> 416
