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26 <div class="titlepage"><div><div><h5 class="title">
27 <a name="geometry.reference.algorithms.is_valid.is_valid_2_with_message"></a><a class="link" href="is_valid_2_with_message.html" title="is_valid (with message)">is_valid
29 </h5></div></div></div>
31 <a class="indexterm" name="idm46186995498896"></a>
32 Checks if a geometry is valid (in the OGC sense)
35 <a name="geometry.reference.algorithms.is_valid.is_valid_2_with_message.h0"></a>
36 <span class="phrase"><a name="geometry.reference.algorithms.is_valid.is_valid_2_with_message.synopsis"></a></span><a class="link" href="is_valid_2_with_message.html#geometry.reference.algorithms.is_valid.is_valid_2_with_message.synopsis">Synopsis</a>
40 <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>
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">&</span> <span class="identifier">geometry</span><span class="special">,</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span> <span class="special">&</span> <span class="identifier">message</span><span class="special">)</span></pre>
45 <a name="geometry.reference.algorithms.is_valid.is_valid_2_with_message.h1"></a>
46 <span class="phrase"><a name="geometry.reference.algorithms.is_valid.is_valid_2_with_message.parameters"></a></span><a class="link" href="is_valid_2_with_message.html#geometry.reference.algorithms.is_valid.is_valid_2_with_message.parameters">Parameters</a>
48 <div class="informaltable"><table class="table">
86 Any type fulfilling a Geometry Concept
96 A model of the specified concept
115 A string containing a message stating if the geometry is valid
116 or not, and if not valid a reason why
123 <a name="geometry.reference.algorithms.is_valid.is_valid_2_with_message.h2"></a>
124 <span class="phrase"><a name="geometry.reference.algorithms.is_valid.is_valid_2_with_message.returns"></a></span><a class="link" href="is_valid_2_with_message.html#geometry.reference.algorithms.is_valid.is_valid_2_with_message.returns">Returns</a>
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
133 <a name="geometry.reference.algorithms.is_valid.is_valid_2_with_message.h3"></a>
134 <span class="phrase"><a name="geometry.reference.algorithms.is_valid.is_valid_2_with_message.header"></a></span><a class="link" href="is_valid_2_with_message.html#geometry.reference.algorithms.is_valid.is_valid_2_with_message.header">Header</a>
140 <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>
146 <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>
149 <a name="geometry.reference.algorithms.is_valid.is_valid_2_with_message.h4"></a>
150 <span class="phrase"><a name="geometry.reference.algorithms.is_valid.is_valid_2_with_message.conformance"></a></span><a class="link" href="is_valid_2_with_message.html#geometry.reference.algorithms.is_valid.is_valid_2_with_message.conformance">Conformance</a>
153 The function is_valid is not defined by OGC.
156 <a name="geometry.reference.algorithms.is_valid.is_valid_2_with_message.h5"></a>
157 <span class="phrase"><a name="geometry.reference.algorithms.is_valid.is_valid_2_with_message.supported_geometries"></a></span><a class="link" href="is_valid_2_with_message.html#geometry.reference.algorithms.is_valid.is_valid_2_with_message.supported_geometries">Supported
160 <div class="informaltable"><table class="table">
186 <span class="inlinemediaobject"><img src="../../../../img/ok.png" alt="ok"></span>
198 <span class="inlinemediaobject"><img src="../../../../img/ok.png" alt="ok"></span>
210 <span class="inlinemediaobject"><img src="../../../../img/ok.png" alt="ok"></span>
222 <span class="inlinemediaobject"><img src="../../../../img/ok.png" alt="ok"></span>
234 <span class="inlinemediaobject"><img src="../../../../img/ok.png" alt="ok"></span>
246 <span class="inlinemediaobject"><img src="../../../../img/ok.png" alt="ok"></span>
258 <span class="inlinemediaobject"><img src="../../../../img/ok.png" alt="ok"></span>
270 <span class="inlinemediaobject"><img src="../../../../img/ok.png" alt="ok"></span>
282 <span class="inlinemediaobject"><img src="../../../../img/ok.png" alt="ok"></span>
294 <span class="inlinemediaobject"><img src="../../../../img/ok.png" alt="ok"></span>
301 <a name="geometry.reference.algorithms.is_valid.is_valid_2_with_message.h6"></a>
302 <span class="phrase"><a name="geometry.reference.algorithms.is_valid.is_valid_2_with_message.complexity"></a></span><a class="link" href="is_valid_2_with_message.html#geometry.reference.algorithms.is_valid.is_valid_2_with_message.complexity">Complexity</a>
305 Constant-time for points, segments, boxes and multi-points
308 Linear for linestrings and multi-linestrings
311 Linearithmic for rings
314 Currently, worst-case quadratic for polygons and multi-polygons
317 <a name="geometry.reference.algorithms.is_valid.is_valid_2_with_message.h7"></a>
318 <span class="phrase"><a name="geometry.reference.algorithms.is_valid.is_valid_2_with_message.example"></a></span><a class="link" href="is_valid_2_with_message.html#geometry.reference.algorithms.is_valid.is_valid_2_with_message.example">Example</a>
321 Checks whether a geometry is valid and, if not valid, prints a message
322 describing the reason
326 <pre class="programlisting"><span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">iostream</span><span class="special">></span>
327 <span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">string</span><span class="special">></span>
329 <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>
330 <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>
331 <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>
334 <span class="keyword">int</span> <span class="identifier">main</span><span class="special">()</span>
335 <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">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>
337 <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>
339 <span class="identifier">polygon_type</span> <span class="identifier">poly</span><span class="special">;</span>
340 <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>
342 <span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span> <span class="identifier">message</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">message</span><span class="special">);</span>
344 <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">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"><<</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">endl</span><span class="special">;</span>
345 <span class="keyword">if</span> <span class="special">(!</span> <span class="identifier">valid</span><span class="special">)</span>
346 <span class="special">{</span>
347 <span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special"><<</span> <span class="string">"why not valid? "</span> <span class="special"><<</span> <span class="identifier">message</span> <span class="special"><<</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">endl</span><span class="special">;</span>
348 <span class="special">}</span>
350 <span class="keyword">return</span> <span class="number">0</span><span class="special">;</span>
351 <span class="special">}</span>
358 <pre class="programlisting">is valid? no
359 why not valid? Geometry has disconnected interior
361 <img src="../../../../img/algorithms/is_valid_example.png" alt="is_valid_example">
365 <a name="geometry.reference.algorithms.is_valid.is_valid_2_with_message.h8"></a>
366 <span class="phrase"><a name="geometry.reference.algorithms.is_valid.is_valid_2_with_message.see_also"></a></span><a class="link" href="is_valid_2_with_message.html#geometry.reference.algorithms.is_valid.is_valid_2_with_message.see_also">See
369 <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem">
370 <a class="link" href="../is_simple.html" title="is_simple">is_simple</a>
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