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  26 <div class="titlepage"><div><div><h5 class="title">
  27 <a name="geometry.reference.algorithms.is_valid.is_valid_3_with_failure_value_and_strategy"></a><a class="link" href="is_valid_3_with_failure_value_and_strategy.html" title="is_valid (with failure value and strategy)">is_valid
  28           (with failure value and strategy)</a>
  29 </h5></div></div></div>
  30 <p>
  31             <a class="indexterm" name="idm46186996333360"></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_3_with_failure_value_and_strategy.h0"></a>
  36             <span class="phrase"><a name="geometry.reference.algorithms.is_valid.is_valid_3_with_failure_value_and_strategy.synopsis"></a></span><a class="link" href="is_valid_3_with_failure_value_and_strategy.html#geometry.reference.algorithms.is_valid.is_valid_3_with_failure_value_and_strategy.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">,</span> <span class="keyword">typename</span> <span class="identifier">Strategy</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> <span class="identifier">Strategy</span> <span class="keyword">const</span> <span class="special">&amp;</span> <span class="identifier">strategy</span><span class="special">)</span></pre>
  42 <p>
  43           </p>
  44 <h6>
  45 <a name="geometry.reference.algorithms.is_valid.is_valid_3_with_failure_value_and_strategy.h1"></a>
  46             <span class="phrase"><a name="geometry.reference.algorithms.is_valid.is_valid_3_with_failure_value_and_strategy.parameters"></a></span><a class="link" href="is_valid_3_with_failure_value_and_strategy.html#geometry.reference.algorithms.is_valid.is_valid_3_with_failure_value_and_strategy.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 <tr>
 121 <td>
 122                     <p>
 123                       Strategy const &amp;
 124                     </p>
 125                   </td>
 126 <td>
 127                     <p>
 128                       Any type fulfilling a Is_valid Strategy Concept
 129                     </p>
 130                   </td>
 131 <td>
 132                     <p>
 133                       strategy
 134                     </p>
 135                   </td>
 136 <td>
 137                     <p>
 138                       The strategy which will be used for is_valid calculations
 139                     </p>
 140                   </td>
 141 </tr>
 142 </tbody>
 143 </table></div>
 144 <h6>
 145 <a name="geometry.reference.algorithms.is_valid.is_valid_3_with_failure_value_and_strategy.h2"></a>
 146             <span class="phrase"><a name="geometry.reference.algorithms.is_valid.is_valid_3_with_failure_value_and_strategy.returns"></a></span><a class="link" href="is_valid_3_with_failure_value_and_strategy.html#geometry.reference.algorithms.is_valid.is_valid_3_with_failure_value_and_strategy.returns">Returns</a>
 147           </h6>
 148 <p>
 149             Returns true if the geometry is valid (in the OGC sense); furthermore,
 150             the following geometries are considered valid: multi-geometries with
 151             no elements, linear geometries containing spikes, areal geometries with
 152             duplicate (consecutive) points
 153           </p>
 154 <h6>
 155 <a name="geometry.reference.algorithms.is_valid.is_valid_3_with_failure_value_and_strategy.h3"></a>
 156             <span class="phrase"><a name="geometry.reference.algorithms.is_valid.is_valid_3_with_failure_value_and_strategy.header"></a></span><a class="link" href="is_valid_3_with_failure_value_and_strategy.html#geometry.reference.algorithms.is_valid.is_valid_3_with_failure_value_and_strategy.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">&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>
 163           </p>
 164 <p>
 165             Or
 166           </p>
 167 <p>
 168             <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>
 169           </p>
 170 <h6>
 171 <a name="geometry.reference.algorithms.is_valid.is_valid_3_with_failure_value_and_strategy.h4"></a>
 172             <span class="phrase"><a name="geometry.reference.algorithms.is_valid.is_valid_3_with_failure_value_and_strategy.conformance"></a></span><a class="link" href="is_valid_3_with_failure_value_and_strategy.html#geometry.reference.algorithms.is_valid.is_valid_3_with_failure_value_and_strategy.conformance">Conformance</a>
 173           </h6>
 174 <p>
 175             The function is_valid is not defined by OGC.
 176           </p>
 177 <h6>
 178 <a name="geometry.reference.algorithms.is_valid.is_valid_3_with_failure_value_and_strategy.h5"></a>
 179             <span class="phrase"><a name="geometry.reference.algorithms.is_valid.is_valid_3_with_failure_value_and_strategy.supported_geometries"></a></span><a class="link" href="is_valid_3_with_failure_value_and_strategy.html#geometry.reference.algorithms.is_valid.is_valid_3_with_failure_value_and_strategy.supported_geometries">Supported
 180             geometries</a>
 181           </h6>
 182 <div class="informaltable"><table class="table">
 183 <colgroup>
 184 <col>
 185 <col>
 186 </colgroup>
 187 <thead><tr>
 188 <th>
 189                     <p>
 190                       Geometry
 191                     </p>
 192                   </th>
 193 <th>
 194                     <p>
 195                       Status
 196                     </p>
 197                   </th>
 198 </tr></thead>
 199 <tbody>
 200 <tr>
 201 <td>
 202                     <p>
 203                       Point
 204                     </p>
 205                   </td>
 206 <td>
 207                     <p>
 208                       <span class="inlinemediaobject"><img src="../../../../img/ok.png" alt="ok"></span>
 209                     </p>
 210                   </td>
 211 </tr>
 212 <tr>
 213 <td>
 214                     <p>
 215                       Segment
 216                     </p>
 217                   </td>
 218 <td>
 219                     <p>
 220                       <span class="inlinemediaobject"><img src="../../../../img/ok.png" alt="ok"></span>
 221                     </p>
 222                   </td>
 223 </tr>
 224 <tr>
 225 <td>
 226                     <p>
 227                       Box
 228                     </p>
 229                   </td>
 230 <td>
 231                     <p>
 232                       <span class="inlinemediaobject"><img src="../../../../img/ok.png" alt="ok"></span>
 233                     </p>
 234                   </td>
 235 </tr>
 236 <tr>
 237 <td>
 238                     <p>
 239                       Linestring
 240                     </p>
 241                   </td>
 242 <td>
 243                     <p>
 244                       <span class="inlinemediaobject"><img src="../../../../img/ok.png" alt="ok"></span>
 245                     </p>
 246                   </td>
 247 </tr>
 248 <tr>
 249 <td>
 250                     <p>
 251                       Ring
 252                     </p>
 253                   </td>
 254 <td>
 255                     <p>
 256                       <span class="inlinemediaobject"><img src="../../../../img/ok.png" alt="ok"></span>
 257                     </p>
 258                   </td>
 259 </tr>
 260 <tr>
 261 <td>
 262                     <p>
 263                       Polygon
 264                     </p>
 265                   </td>
 266 <td>
 267                     <p>
 268                       <span class="inlinemediaobject"><img src="../../../../img/ok.png" alt="ok"></span>
 269                     </p>
 270                   </td>
 271 </tr>
 272 <tr>
 273 <td>
 274                     <p>
 275                       MultiPoint
 276                     </p>
 277                   </td>
 278 <td>
 279                     <p>
 280                       <span class="inlinemediaobject"><img src="../../../../img/ok.png" alt="ok"></span>
 281                     </p>
 282                   </td>
 283 </tr>
 284 <tr>
 285 <td>
 286                     <p>
 287                       MultiLinestring
 288                     </p>
 289                   </td>
 290 <td>
 291                     <p>
 292                       <span class="inlinemediaobject"><img src="../../../../img/ok.png" alt="ok"></span>
 293                     </p>
 294                   </td>
 295 </tr>
 296 <tr>
 297 <td>
 298                     <p>
 299                       MultiPolygon
 300                     </p>
 301                   </td>
 302 <td>
 303                     <p>
 304                       <span class="inlinemediaobject"><img src="../../../../img/ok.png" alt="ok"></span>
 305                     </p>
 306                   </td>
 307 </tr>
 308 <tr>
 309 <td>
 310                     <p>
 311                       Variant
 312                     </p>
 313                   </td>
 314 <td>
 315                     <p>
 316                       <span class="inlinemediaobject"><img src="../../../../img/ok.png" alt="ok"></span>
 317                     </p>
 318                   </td>
 319 </tr>
 320 </tbody>
 321 </table></div>
 322 <h6>
 323 <a name="geometry.reference.algorithms.is_valid.is_valid_3_with_failure_value_and_strategy.h6"></a>
 324             <span class="phrase"><a name="geometry.reference.algorithms.is_valid.is_valid_3_with_failure_value_and_strategy.complexity"></a></span><a class="link" href="is_valid_3_with_failure_value_and_strategy.html#geometry.reference.algorithms.is_valid.is_valid_3_with_failure_value_and_strategy.complexity">Complexity</a>
 325           </h6>
 326 <p>
 327             Constant-time for points, segments, boxes and multi-points
 328           </p>
 329 <p>
 330             Linear for linestrings and multi-linestrings
 331           </p>
 332 <p>
 333             Linearithmic for rings
 334           </p>
 335 <p>
 336             Currently, worst-case quadratic for polygons and multi-polygons
 337           </p>
 338 <h6>
 339 <a name="geometry.reference.algorithms.is_valid.is_valid_3_with_failure_value_and_strategy.h7"></a>
 340             <span class="phrase"><a name="geometry.reference.algorithms.is_valid.is_valid_3_with_failure_value_and_strategy.example"></a></span><a class="link" href="is_valid_3_with_failure_value_and_strategy.html#geometry.reference.algorithms.is_valid.is_valid_3_with_failure_value_and_strategy.example">Example</a>
 341           </h6>
 342 <p>
 343             Checks whether a geometry is valid and, if not valid, checks if it could
 344             be fixed by bg::correct; if so bg::correct is called on the geometry
 345           </p>
 346 <p>
 347 </p>
 348 <pre class="programlisting"><span class="preprocessor">#include</span> <span class="special">&lt;</span><span class="identifier">iostream</span><span class="special">&gt;</span>
 349
 350 <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>
 351 <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>
 352 <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>
 353
 354
 355 <span class="keyword">int</span> <span class="identifier">main</span><span class="special">()</span>
 356 <span class="special">{</span>
 357     <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>
 358     <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>
 359
 360     <span class="identifier">polygon_type</span> <span class="identifier">poly</span><span class="special">;</span>
 361     <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>
 362
 363     <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>
 364     <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>
 365     <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>
 366
 367     <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>
 368     <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>
 369                            <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>
 370     <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>
 371     <span class="keyword">if</span> <span class="special">(!</span> <span class="identifier">valid</span><span class="special">)</span>
 372     <span class="special">{</span>
 373         <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>
 374         <span class="keyword">if</span> <span class="special">(</span><span class="identifier">could_be_fixed</span><span class="special">)</span>
 375         <span class="special">{</span>
 376             <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>
 377             <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>
 378             <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>
 379         <span class="special">}</span>
 380     <span class="special">}</span>
 381
 382     <span class="keyword">return</span> <span class="number">0</span><span class="special">;</span>
 383 <span class="special">}</span>
 384 </pre>
 385 <p>
 386           </p>
 387 <p>
 388             Output:
 389           </p>
 390 <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)))
 391 is valid? no
 392 can boost::geometry::correct remedy invalidity? possibly yes
 393 after correction: valid
 394 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)))
 395
 396 <img src="../../../../img/algorithms/is_valid_failure_example.png" alt="is_valid_failure_example">
 397
 398 </pre>
 399 <h6>
 400 <a name="geometry.reference.algorithms.is_valid.is_valid_3_with_failure_value_and_strategy.h8"></a>
 401             <span class="phrase"><a name="geometry.reference.algorithms.is_valid.is_valid_3_with_failure_value_and_strategy.see_also"></a></span><a class="link" href="is_valid_3_with_failure_value_and_strategy.html#geometry.reference.algorithms.is_valid.is_valid_3_with_failure_value_and_strategy.see_also">See
 402             also</a>
 403           </h6>
 404 <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
 405 <li class="listitem">
 406                 <a class="link" href="../is_simple.html" title="is_simple">is_simple</a>
 407               </li>
 408 <li class="listitem">
 409                 <a class="link" href="../../enumerations/validity_failure_type.html" title="validity_failure_type">validity_failure_type</a>
 410               </li>
 411 </ul></div>
 412 </div>
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 415 <td align="right"><div class="copyright-footer">Copyright &#169; 2009-2019 Barend Gehrels, Bruno Lalande, Mateusz Loskot, Adam
 416       Wulkiewicz, Oracle and/or its affiliates<p>
 417         Distributed under the Boost Software License, Version 1.0. (See accompanying
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