libs/geometry/doc/html/geometry/reference/algorithms/is_valid/is_valid_2_with_failure_value.html

   1 <html>
   2 <head>
   3 <meta http-equiv="Content-Type" content="text/html; charset=US-ASCII">
   4 <title>is_valid (with failure value)</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&#160;1.&#160;Geometry">
   8 <link rel="up" href="../is_valid.html" title="is_valid">
   9 <link rel="prev" href="is_valid_3_with_failure_value_and_strategy.html" title="is_valid (with failure value and strategy)">
  10 <link rel="next" href="is_valid_3_with_message_and_strategy.html" title="is_valid (with message 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_3_with_failure_value_and_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_message_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_2_with_failure_value"></a><a class="link" href="is_valid_2_with_failure_value.html" title="is_valid (with failure value)">is_valid
  28           (with failure value)</a>
  29 </h5></div></div></div>
  30 <p>
  31             <a class="indexterm" name="idm46186996057888"></a>
  32 Checks if a geometry is valid (in the OGC sense)
  33           </p>
  34 <h6>
  35 <a name="geometry.reference.algorithms.is_valid.is_valid_2_with_failure_value.h0"></a>
  36             <span class="phrase"><a name="geometry.reference.algorithms.is_valid.is_valid_2_with_failure_value.synopsis"></a></span><a class="link" href="is_valid_2_with_failure_value.html#geometry.reference.algorithms.is_valid.is_valid_2_with_failure_value.synopsis">Synopsis</a>
  37           </h6>
  38 <p>
  39 </p>
  40 <pre class="programlisting"><span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">typename</span> <span class="identifier">Geometry</span><span class="special">&gt;</span>
  41 <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">&amp;</span> <span class="identifier">geometry</span><span class="special">,</span> <span class="identifier">validity_failure_type</span> <span class="special">&amp;</span> <span class="identifier">failure</span><span class="special">)</span></pre>
  42 <p>
  43           </p>
  44 <h6>
  45 <a name="geometry.reference.algorithms.is_valid.is_valid_2_with_failure_value.h1"></a>
  46             <span class="phrase"><a name="geometry.reference.algorithms.is_valid.is_valid_2_with_failure_value.parameters"></a></span><a class="link" href="is_valid_2_with_failure_value.html#geometry.reference.algorithms.is_valid.is_valid_2_with_failure_value.parameters">Parameters</a>
  47           </h6>
  48 <div class="informaltable"><table class="table">
  49 <colgroup>
  50 <col>
  51 <col>
  52 <col>
  53 <col>
  54 </colgroup>
  55 <thead><tr>
  56 <th>
  57                     <p>
  58                       Type
  59                     </p>
  60                   </th>
  61 <th>
  62                     <p>
  63                       Concept
  64                     </p>
  65                   </th>
  66 <th>
  67                     <p>
  68                       Name
  69                     </p>
  70                   </th>
  71 <th>
  72                     <p>
  73                       Description
  74                     </p>
  75                   </th>
  76 </tr></thead>
  77 <tbody>
  78 <tr>
  79 <td>
  80                     <p>
  81                       Geometry const &amp;
  82                     </p>
  83                   </td>
  84 <td>
  85                     <p>
  86                       Any type fulfilling a Geometry Concept
  87                     </p>
  88                   </td>
  89 <td>
  90                     <p>
  91                       geometry
  92                     </p>
  93                   </td>
  94 <td>
  95                     <p>
  96                       A model of the specified concept
  97                     </p>
  98                   </td>
  99 </tr>
 100 <tr>
 101 <td>
 102                     <p>
 103                       validity_failure_type &amp;
 104                     </p>
 105                   </td>
 106 <td>
 107                   </td>
 108 <td>
 109                     <p>
 110                       failure
 111                     </p>
 112                   </td>
 113 <td>
 114                     <p>
 115                       An enumeration value indicating that the geometry is valid
 116                       or not, and if not valid indicating the reason why
 117                     </p>
 118                   </td>
 119 </tr>
 120 </tbody>
 121 </table></div>
 122 <h6>
 123 <a name="geometry.reference.algorithms.is_valid.is_valid_2_with_failure_value.h2"></a>
 124             <span class="phrase"><a name="geometry.reference.algorithms.is_valid.is_valid_2_with_failure_value.returns"></a></span><a class="link" href="is_valid_2_with_failure_value.html#geometry.reference.algorithms.is_valid.is_valid_2_with_failure_value.returns">Returns</a>
 125           </h6>
 126 <p>
 127             Returns true if the geometry is valid (in the OGC sense); furthermore,
 128             the following geometries are considered valid: multi-geometries with
 129             no elements, linear geometries containing spikes, areal geometries with
 130             duplicate (consecutive) points
 131           </p>
 132 <h6>
 133 <a name="geometry.reference.algorithms.is_valid.is_valid_2_with_failure_value.h3"></a>
 134             <span class="phrase"><a name="geometry.reference.algorithms.is_valid.is_valid_2_with_failure_value.header"></a></span><a class="link" href="is_valid_2_with_failure_value.html#geometry.reference.algorithms.is_valid.is_valid_2_with_failure_value.header">Header</a>
 135           </h6>
 136 <p>
 137             Either
 138           </p>
 139 <p>
 140             <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>
 141           </p>
 142 <p>
 143             Or
 144           </p>
 145 <p>
 146             <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">is_valid</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">&gt;</span></code>
 147           </p>
 148 <h6>
 149 <a name="geometry.reference.algorithms.is_valid.is_valid_2_with_failure_value.h4"></a>
 150             <span class="phrase"><a name="geometry.reference.algorithms.is_valid.is_valid_2_with_failure_value.conformance"></a></span><a class="link" href="is_valid_2_with_failure_value.html#geometry.reference.algorithms.is_valid.is_valid_2_with_failure_value.conformance">Conformance</a>
 151           </h6>
 152 <p>
 153             The function is_valid is not defined by OGC.
 154           </p>
 155 <h6>
 156 <a name="geometry.reference.algorithms.is_valid.is_valid_2_with_failure_value.h5"></a>
 157             <span class="phrase"><a name="geometry.reference.algorithms.is_valid.is_valid_2_with_failure_value.supported_geometries"></a></span><a class="link" href="is_valid_2_with_failure_value.html#geometry.reference.algorithms.is_valid.is_valid_2_with_failure_value.supported_geometries">Supported
 158             geometries</a>
 159           </h6>
 160 <div class="informaltable"><table class="table">
 161 <colgroup>
 162 <col>
 163 <col>
 164 </colgroup>
 165 <thead><tr>
 166 <th>
 167                     <p>
 168                       Geometry
 169                     </p>
 170                   </th>
 171 <th>
 172                     <p>
 173                       Status
 174                     </p>
 175                   </th>
 176 </tr></thead>
 177 <tbody>
 178 <tr>
 179 <td>
 180                     <p>
 181                       Point
 182                     </p>
 183                   </td>
 184 <td>
 185                     <p>
 186                       <span class="inlinemediaobject"><img src="../../../../img/ok.png" alt="ok"></span>
 187                     </p>
 188                   </td>
 189 </tr>
 190 <tr>
 191 <td>
 192                     <p>
 193                       Segment
 194                     </p>
 195                   </td>
 196 <td>
 197                     <p>
 198                       <span class="inlinemediaobject"><img src="../../../../img/ok.png" alt="ok"></span>
 199                     </p>
 200                   </td>
 201 </tr>
 202 <tr>
 203 <td>
 204                     <p>
 205                       Box
 206                     </p>
 207                   </td>
 208 <td>
 209                     <p>
 210                       <span class="inlinemediaobject"><img src="../../../../img/ok.png" alt="ok"></span>
 211                     </p>
 212                   </td>
 213 </tr>
 214 <tr>
 215 <td>
 216                     <p>
 217                       Linestring
 218                     </p>
 219                   </td>
 220 <td>
 221                     <p>
 222                       <span class="inlinemediaobject"><img src="../../../../img/ok.png" alt="ok"></span>
 223                     </p>
 224                   </td>
 225 </tr>
 226 <tr>
 227 <td>
 228                     <p>
 229                       Ring
 230                     </p>
 231                   </td>
 232 <td>
 233                     <p>
 234                       <span class="inlinemediaobject"><img src="../../../../img/ok.png" alt="ok"></span>
 235                     </p>
 236                   </td>
 237 </tr>
 238 <tr>
 239 <td>
 240                     <p>
 241                       Polygon
 242                     </p>
 243                   </td>
 244 <td>
 245                     <p>
 246                       <span class="inlinemediaobject"><img src="../../../../img/ok.png" alt="ok"></span>
 247                     </p>
 248                   </td>
 249 </tr>
 250 <tr>
 251 <td>
 252                     <p>
 253                       MultiPoint
 254                     </p>
 255                   </td>
 256 <td>
 257                     <p>
 258                       <span class="inlinemediaobject"><img src="../../../../img/ok.png" alt="ok"></span>
 259                     </p>
 260                   </td>
 261 </tr>
 262 <tr>
 263 <td>
 264                     <p>
 265                       MultiLinestring
 266                     </p>
 267                   </td>
 268 <td>
 269                     <p>
 270                       <span class="inlinemediaobject"><img src="../../../../img/ok.png" alt="ok"></span>
 271                     </p>
 272                   </td>
 273 </tr>
 274 <tr>
 275 <td>
 276                     <p>
 277                       MultiPolygon
 278                     </p>
 279                   </td>
 280 <td>
 281                     <p>
 282                       <span class="inlinemediaobject"><img src="../../../../img/ok.png" alt="ok"></span>
 283                     </p>
 284                   </td>
 285 </tr>
 286 <tr>
 287 <td>
 288                     <p>
 289                       Variant
 290                     </p>
 291                   </td>
 292 <td>
 293                     <p>
 294                       <span class="inlinemediaobject"><img src="../../../../img/ok.png" alt="ok"></span>
 295                     </p>
 296                   </td>
 297 </tr>
 298 </tbody>
 299 </table></div>
 300 <h6>
 301 <a name="geometry.reference.algorithms.is_valid.is_valid_2_with_failure_value.h6"></a>
 302             <span class="phrase"><a name="geometry.reference.algorithms.is_valid.is_valid_2_with_failure_value.complexity"></a></span><a class="link" href="is_valid_2_with_failure_value.html#geometry.reference.algorithms.is_valid.is_valid_2_with_failure_value.complexity">Complexity</a>
 303           </h6>
 304 <p>
 305             Constant-time for points, segments, boxes and multi-points
 306           </p>
 307 <p>
 308             Linear for linestrings and multi-linestrings
 309           </p>
 310 <p>
 311             Linearithmic for rings
 312           </p>
 313 <p>
 314             Currently, worst-case quadratic for polygons and multi-polygons
 315           </p>
 316 <h6>
 317 <a name="geometry.reference.algorithms.is_valid.is_valid_2_with_failure_value.h7"></a>
 318             <span class="phrase"><a name="geometry.reference.algorithms.is_valid.is_valid_2_with_failure_value.example"></a></span><a class="link" href="is_valid_2_with_failure_value.html#geometry.reference.algorithms.is_valid.is_valid_2_with_failure_value.example">Example</a>
 319           </h6>
 320 <p>
 321             Checks whether a geometry is valid and, if not valid, checks if it could
 322             be fixed by bg::correct; if so bg::correct is called on the geometry
 323           </p>
 324 <p>
 325 </p>
 326 <pre class="programlisting"><span class="preprocessor">#include</span> <span class="special">&lt;</span><span class="identifier">iostream</span><span class="special">&gt;</span>
 327
 328 <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>
 329 <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">geometries</span><span class="special">/</span><span class="identifier">point_xy</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">&gt;</span>
 330 <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">geometries</span><span class="special">/</span><span class="identifier">polygon</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">&gt;</span>
 331
 332
 333 <span class="keyword">int</span> <span class="identifier">main</span><span class="special">()</span>
 334 <span class="special">{</span>
 335     <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">&lt;</span><span class="keyword">double</span><span class="special">&gt;</span> <span class="identifier">point_type</span><span class="special">;</span>
 336     <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">&lt;</span><span class="identifier">point_type</span><span class="special">&gt;</span> <span class="identifier">polygon_type</span><span class="special">;</span>
 337
 338     <span class="identifier">polygon_type</span> <span class="identifier">poly</span><span class="special">;</span>
 339     <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 0,9 2,9 1,0 0),(0 0,2 9,1 9,0 0))"</span><span class="special">,</span> <span class="identifier">poly</span><span class="special">);</span>
 340
 341     <span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special">&lt;&lt;</span> <span class="string">"original geometry: "</span> <span class="special">&lt;&lt;</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">geometry</span><span class="special">::</span><span class="identifier">dsv</span><span class="special">(</span><span class="identifier">poly</span><span class="special">)</span> <span class="special">&lt;&lt;</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">endl</span><span class="special">;</span>
 342     <span class="identifier">boost</span><span class="special">::</span><span class="identifier">geometry</span><span class="special">::</span><span class="identifier">validity_failure_type</span> <span class="identifier">failure</span><span class="special">;</span>
 343     <span class="keyword">bool</span> <span class="identifier">valid</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="identifier">failure</span><span class="special">);</span>
 344
 345     <span class="comment">// if the invalidity is only due to lack of closing points and/or wrongly oriented rings, then bg::correct can fix it</span>
 346     <span class="keyword">bool</span> <span class="identifier">could_be_fixed</span> <span class="special">=</span> <span class="special">(</span><span class="identifier">failure</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">failure_not_closed</span>
 347                            <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">failure_wrong_orientation</span><span class="special">);</span>
 348     <span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special">&lt;&lt;</span> <span class="string">"is valid? "</span> <span class="special">&lt;&lt;</span> <span class="special">(</span><span class="identifier">valid</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">&lt;&lt;</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">endl</span><span class="special">;</span>
 349     <span class="keyword">if</span> <span class="special">(!</span> <span class="identifier">valid</span><span class="special">)</span>
 350     <span class="special">{</span>
 351         <span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special">&lt;&lt;</span> <span class="string">"can boost::geometry::correct remedy invalidity? "</span> <span class="special">&lt;&lt;</span> <span class="special">(</span><span class="identifier">could_be_fixed</span> <span class="special">?</span> <span class="string">"possibly yes"</span> <span class="special">:</span> <span class="string">"no"</span><span class="special">)</span> <span class="special">&lt;&lt;</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">endl</span><span class="special">;</span>
 352         <span class="keyword">if</span> <span class="special">(</span><span class="identifier">could_be_fixed</span><span class="special">)</span>
 353         <span class="special">{</span>
 354             <span class="identifier">boost</span><span class="special">::</span><span class="identifier">geometry</span><span class="special">::</span><span class="identifier">correct</span><span class="special">(</span><span class="identifier">poly</span><span class="special">);</span>
 355             <span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special">&lt;&lt;</span> <span class="string">"after correction: "</span> <span class="special">&lt;&lt;</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">"valid"</span> <span class="special">:</span> <span class="string">"still invalid"</span><span class="special">)</span> <span class="special">&lt;&lt;</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">endl</span><span class="special">;</span>
 356             <span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special">&lt;&lt;</span> <span class="string">"corrected geometry: "</span> <span class="special">&lt;&lt;</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">geometry</span><span class="special">::</span><span class="identifier">dsv</span><span class="special">(</span><span class="identifier">poly</span><span class="special">)</span> <span class="special">&lt;&lt;</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">endl</span><span class="special">;</span>
 357         <span class="special">}</span>
 358     <span class="special">}</span>
 359
 360     <span class="keyword">return</span> <span class="number">0</span><span class="special">;</span>
 361 <span class="special">}</span>
 362 </pre>
 363 <p>
 364           </p>
 365 <p>
 366             Output:
 367           </p>
 368 <pre class="programlisting">original geometry: (((0, 0), (0, 10), (10, 10), (10, 0)), ((0, 0), (9, 2), (9, 1), (0, 0)), ((0, 0), (2, 9), (1, 9), (0, 0)))
 369 is valid? no
 370 can boost::geometry::correct remedy invalidity? possibly yes
 371 after correction: valid
 372 corrected geometry: (((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)))
 373
 374 <img src="../../../../img/algorithms/is_valid_failure_example.png" alt="is_valid_failure_example">
 375
 376 </pre>
 377 <h6>
 378 <a name="geometry.reference.algorithms.is_valid.is_valid_2_with_failure_value.h8"></a>
 379             <span class="phrase"><a name="geometry.reference.algorithms.is_valid.is_valid_2_with_failure_value.see_also"></a></span><a class="link" href="is_valid_2_with_failure_value.html#geometry.reference.algorithms.is_valid.is_valid_2_with_failure_value.see_also">See
 380             also</a>
 381           </h6>
 382 <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
 383 <li class="listitem">
 384                 <a class="link" href="../is_simple.html" title="is_simple">is_simple</a>
 385               </li>
 386 <li class="listitem">
 387                 <a class="link" href="../../enumerations/validity_failure_type.html" title="validity_failure_type">validity_failure_type</a>
 388               </li>
 389 </ul></div>
 390 </div>
 391 <table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
 392 <td align="left"></td>
 393 <td align="right"><div class="copyright-footer">Copyright &#169; 2009-2019 Barend Gehrels, Bruno Lalande, Mateusz Loskot, Adam
 394       Wulkiewicz, Oracle and/or its affiliates<p>
 395         Distributed under the Boost Software License, Version 1.0. (See accompanying
 396         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>)
 397       </p>
 398 </div></td>
 399 </tr></table>
 400 <hr>
 401 <div class="spirit-nav">
 402 <a accesskey="p" href="is_valid_3_with_failure_value_and_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_message_and_strategy.html"><img src="../../../../../../../../doc/src/images/next.png" alt="Next"></a>
 403 </div>
 404 </body>
 405 </html>