1<html> 2<head> 3<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 4<title>is_valid</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="../is_valid.html" title="is_valid"> 9<link rel="prev" href="is_valid_2_with_strategy.html" title="is_valid (with strategy)"> 10<link rel="next" href="is_valid_3_with_failure_value_and_strategy.html" title="is_valid (with failure value and strategy)"> 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="is_valid_2_with_strategy.html"><img src="../../../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../is_valid.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="is_valid_3_with_failure_value_and_strategy.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.is_valid.is_valid_1"></a><a class="link" href="is_valid_1.html" title="is_valid">is_valid</a> 28</h5></div></div></div> 29<p> 30 <a class="indexterm" name="idm45635694319136"></a> 31Checks if a geometry is valid (in the OGC sense) 32 </p> 33<h6> 34<a name="geometry.reference.algorithms.is_valid.is_valid_1.h0"></a> 35 <span class="phrase"><a name="geometry.reference.algorithms.is_valid.is_valid_1.synopsis"></a></span><a class="link" href="is_valid_1.html#geometry.reference.algorithms.is_valid.is_valid_1.synopsis">Synopsis</a> 36 </h6> 37<p> 38</p> 39<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> 40<span class="keyword">bool</span> <span class="identifier">is_valid</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></pre> 41<p> 42 </p> 43<h6> 44<a name="geometry.reference.algorithms.is_valid.is_valid_1.h1"></a> 45 <span class="phrase"><a name="geometry.reference.algorithms.is_valid.is_valid_1.parameters"></a></span><a class="link" href="is_valid_1.html#geometry.reference.algorithms.is_valid.is_valid_1.parameters">Parameters</a> 46 </h6> 47<div class="informaltable"><table class="table"> 48<colgroup> 49<col> 50<col> 51<col> 52<col> 53</colgroup> 54<thead><tr> 55<th> 56 <p> 57 Type 58 </p> 59 </th> 60<th> 61 <p> 62 Concept 63 </p> 64 </th> 65<th> 66 <p> 67 Name 68 </p> 69 </th> 70<th> 71 <p> 72 Description 73 </p> 74 </th> 75</tr></thead> 76<tbody><tr> 77<td> 78 <p> 79 Geometry const & 80 </p> 81 </td> 82<td> 83 <p> 84 Any type fulfilling a Geometry Concept 85 </p> 86 </td> 87<td> 88 <p> 89 geometry 90 </p> 91 </td> 92<td> 93 <p> 94 A model of the specified concept 95 </p> 96 </td> 97</tr></tbody> 98</table></div> 99<h6> 100<a name="geometry.reference.algorithms.is_valid.is_valid_1.h2"></a> 101 <span class="phrase"><a name="geometry.reference.algorithms.is_valid.is_valid_1.returns"></a></span><a class="link" href="is_valid_1.html#geometry.reference.algorithms.is_valid.is_valid_1.returns">Returns</a> 102 </h6> 103<p> 104 Returns true if the geometry is valid (in the OGC sense); furthermore, 105 the following geometries are considered valid: multi-geometries with 106 no elements, linear geometries containing spikes, areal geometries with 107 duplicate (consecutive) points 108 </p> 109<h6> 110<a name="geometry.reference.algorithms.is_valid.is_valid_1.h3"></a> 111 <span class="phrase"><a name="geometry.reference.algorithms.is_valid.is_valid_1.header"></a></span><a class="link" href="is_valid_1.html#geometry.reference.algorithms.is_valid.is_valid_1.header">Header</a> 112 </h6> 113<p> 114 Either 115 </p> 116<p> 117 <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> 118 </p> 119<p> 120 Or 121 </p> 122<p> 123 <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">is_valid</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span></code> 124 </p> 125<h6> 126<a name="geometry.reference.algorithms.is_valid.is_valid_1.h4"></a> 127 <span class="phrase"><a name="geometry.reference.algorithms.is_valid.is_valid_1.conformance"></a></span><a class="link" href="is_valid_1.html#geometry.reference.algorithms.is_valid.is_valid_1.conformance">Conformance</a> 128 </h6> 129<p> 130 The function is_valid is not defined by OGC. 131 </p> 132<h6> 133<a name="geometry.reference.algorithms.is_valid.is_valid_1.h5"></a> 134 <span class="phrase"><a name="geometry.reference.algorithms.is_valid.is_valid_1.supported_geometries"></a></span><a class="link" href="is_valid_1.html#geometry.reference.algorithms.is_valid.is_valid_1.supported_geometries">Supported 135 geometries</a> 136 </h6> 137<div class="informaltable"><table class="table"> 138<colgroup> 139<col> 140<col> 141</colgroup> 142<thead><tr> 143<th> 144 <p> 145 Geometry 146 </p> 147 </th> 148<th> 149 <p> 150 Status 151 </p> 152 </th> 153</tr></thead> 154<tbody> 155<tr> 156<td> 157 <p> 158 Point 159 </p> 160 </td> 161<td> 162 <p> 163 <span class="inlinemediaobject"><img src="../../../../img/ok.png" alt="ok"></span> 164 </p> 165 </td> 166</tr> 167<tr> 168<td> 169 <p> 170 Segment 171 </p> 172 </td> 173<td> 174 <p> 175 <span class="inlinemediaobject"><img src="../../../../img/ok.png" alt="ok"></span> 176 </p> 177 </td> 178</tr> 179<tr> 180<td> 181 <p> 182 Box 183 </p> 184 </td> 185<td> 186 <p> 187 <span class="inlinemediaobject"><img src="../../../../img/ok.png" alt="ok"></span> 188 </p> 189 </td> 190</tr> 191<tr> 192<td> 193 <p> 194 Linestring 195 </p> 196 </td> 197<td> 198 <p> 199 <span class="inlinemediaobject"><img src="../../../../img/ok.png" alt="ok"></span> 200 </p> 201 </td> 202</tr> 203<tr> 204<td> 205 <p> 206 Ring 207 </p> 208 </td> 209<td> 210 <p> 211 <span class="inlinemediaobject"><img src="../../../../img/ok.png" alt="ok"></span> 212 </p> 213 </td> 214</tr> 215<tr> 216<td> 217 <p> 218 Polygon 219 </p> 220 </td> 221<td> 222 <p> 223 <span class="inlinemediaobject"><img src="../../../../img/ok.png" alt="ok"></span> 224 </p> 225 </td> 226</tr> 227<tr> 228<td> 229 <p> 230 MultiPoint 231 </p> 232 </td> 233<td> 234 <p> 235 <span class="inlinemediaobject"><img src="../../../../img/ok.png" alt="ok"></span> 236 </p> 237 </td> 238</tr> 239<tr> 240<td> 241 <p> 242 MultiLinestring 243 </p> 244 </td> 245<td> 246 <p> 247 <span class="inlinemediaobject"><img src="../../../../img/ok.png" alt="ok"></span> 248 </p> 249 </td> 250</tr> 251<tr> 252<td> 253 <p> 254 MultiPolygon 255 </p> 256 </td> 257<td> 258 <p> 259 <span class="inlinemediaobject"><img src="../../../../img/ok.png" alt="ok"></span> 260 </p> 261 </td> 262</tr> 263<tr> 264<td> 265 <p> 266 Variant 267 </p> 268 </td> 269<td> 270 <p> 271 <span class="inlinemediaobject"><img src="../../../../img/ok.png" alt="ok"></span> 272 </p> 273 </td> 274</tr> 275</tbody> 276</table></div> 277<h6> 278<a name="geometry.reference.algorithms.is_valid.is_valid_1.h6"></a> 279 <span class="phrase"><a name="geometry.reference.algorithms.is_valid.is_valid_1.complexity"></a></span><a class="link" href="is_valid_1.html#geometry.reference.algorithms.is_valid.is_valid_1.complexity">Complexity</a> 280 </h6> 281<p> 282 Constant-time for points, segments, boxes and multi-points 283 </p> 284<p> 285 Linear for linestrings and multi-linestrings 286 </p> 287<p> 288 Linearithmic for rings 289 </p> 290<p> 291 Currently, worst-case quadratic for polygons and multi-polygons 292 </p> 293<h6> 294<a name="geometry.reference.algorithms.is_valid.is_valid_1.h7"></a> 295 <span class="phrase"><a name="geometry.reference.algorithms.is_valid.is_valid_1.example"></a></span><a class="link" href="is_valid_1.html#geometry.reference.algorithms.is_valid.is_valid_1.example">Example</a> 296 </h6> 297<p> 298 Checks whether a geometry is valid 299 </p> 300<p> 301</p> 302<pre class="programlisting"><span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">iostream</span><span class="special">></span> 303 304<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> 305<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> 306<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> 307 308 309<span class="keyword">int</span> <span class="identifier">main</span><span class="special">()</span> 310<span class="special">{</span> 311 <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">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="identifier">point_type</span><span class="special">;</span> 312 <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">point_type</span><span class="special">></span> <span class="identifier">polygon_type</span><span class="special">;</span> 313 314 <span class="identifier">polygon_type</span> <span class="identifier">poly</span><span class="special">;</span> 315 <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><span class="string">"POLYGON((0 0,0 10,10 10,10 0,0 0),(0 0,9 1,9 2,0 0),(0 0,2 9,1 9,0 0),(2 9,9 2,9 9,2 9))"</span><span class="special">,</span> <span class="identifier">poly</span><span class="special">);</span> 316 317 <span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special"><<</span> <span class="string">"is valid? "</span> <span class="special"><<</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">is_valid</span><span class="special">(</span><span class="identifier">poly</span><span class="special">)</span> <span class="special">?</span> <span class="string">"yes"</span> <span class="special">:</span> <span class="string">"no"</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> 318 319 <span class="keyword">return</span> <span class="number">0</span><span class="special">;</span> 320<span class="special">}</span> 321</pre> 322<p> 323 </p> 324<p> 325 Output: 326 </p> 327<pre class="programlisting">is valid? no 328 329<img src="../../../../img/algorithms/is_valid_example.png" alt="is_valid_example"> 330 331</pre> 332<h6> 333<a name="geometry.reference.algorithms.is_valid.is_valid_1.h8"></a> 334 <span class="phrase"><a name="geometry.reference.algorithms.is_valid.is_valid_1.see_also"></a></span><a class="link" href="is_valid_1.html#geometry.reference.algorithms.is_valid.is_valid_1.see_also">See 335 also</a> 336 </h6> 337<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"> 338 <a class="link" href="../is_simple.html" title="is_simple">is_simple</a> 339 </li></ul></div> 340</div> 341<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> 342<td align="left"></td> 343<td align="right"><div class="copyright-footer">Copyright © 2009-2019 Barend Gehrels, Bruno Lalande, Mateusz Loskot, Adam 344 Wulkiewicz, Oracle and/or its affiliates<p> 345 Distributed under the Boost Software License, Version 1.0. (See accompanying 346 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>) 347 </p> 348</div></td> 349</tr></table> 350<hr> 351<div class="spirit-nav"> 352<a accesskey="p" href="is_valid_2_with_strategy.html"><img src="../../../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../is_valid.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="is_valid_3_with_failure_value_and_strategy.html"><img src="../../../../../../../../doc/src/images/next.png" alt="Next"></a> 353</div> 354</body> 355</html> 356
