1<html> 2<head> 3<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 4<title>num_geometries</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="../algorithms.html" title="Algorithms"> 9<link rel="prev" href="make/make_zero.html" title="make_zero"> 10<link rel="next" href="num_interior_rings.html" title="num_interior_rings"> 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="make/make_zero.html"><img 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href="num_geometries.html#geometry.reference.algorithms.num_geometries.description">Description</a> 36 </h6> 37<p> 38 The free function num_geometries calculates the number of geometries of 39 a geometry. 40 </p> 41<h6> 42<a name="geometry.reference.algorithms.num_geometries.h1"></a> 43 <span class="phrase"><a name="geometry.reference.algorithms.num_geometries.synopsis"></a></span><a class="link" href="num_geometries.html#geometry.reference.algorithms.num_geometries.synopsis">Synopsis</a> 44 </h6> 45<p> 46</p> 47<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> 48<span class="identifier">std</span><span class="special">::</span><span class="identifier">size_t</span> <span class="identifier">num_geometries</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> 49<p> 50 </p> 51<h6> 52<a name="geometry.reference.algorithms.num_geometries.h2"></a> 53 <span class="phrase"><a name="geometry.reference.algorithms.num_geometries.parameters"></a></span><a class="link" href="num_geometries.html#geometry.reference.algorithms.num_geometries.parameters">Parameters</a> 54 </h6> 55<div class="informaltable"><table class="table"> 56<colgroup> 57<col> 58<col> 59<col> 60<col> 61</colgroup> 62<thead><tr> 63<th> 64 <p> 65 Type 66 </p> 67 </th> 68<th> 69 <p> 70 Concept 71 </p> 72 </th> 73<th> 74 <p> 75 Name 76 </p> 77 </th> 78<th> 79 <p> 80 Description 81 </p> 82 </th> 83</tr></thead> 84<tbody><tr> 85<td> 86 <p> 87 Geometry const & 88 </p> 89 </td> 90<td> 91 <p> 92 Any type fulfilling a Geometry Concept 93 </p> 94 </td> 95<td> 96 <p> 97 geometry 98 </p> 99 </td> 100<td> 101 <p> 102 A model of the specified concept 103 </p> 104 </td> 105</tr></tbody> 106</table></div> 107<h6> 108<a name="geometry.reference.algorithms.num_geometries.h3"></a> 109 <span class="phrase"><a name="geometry.reference.algorithms.num_geometries.returns"></a></span><a class="link" href="num_geometries.html#geometry.reference.algorithms.num_geometries.returns">Returns</a> 110 </h6> 111<p> 112 The calculated number of geometries 113 </p> 114<h6> 115<a name="geometry.reference.algorithms.num_geometries.h4"></a> 116 <span class="phrase"><a name="geometry.reference.algorithms.num_geometries.header"></a></span><a class="link" href="num_geometries.html#geometry.reference.algorithms.num_geometries.header">Header</a> 117 </h6> 118<p> 119 Either 120 </p> 121<p> 122 <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> 123 </p> 124<p> 125 Or 126 </p> 127<p> 128 <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">num_geometries</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span></code> 129 </p> 130<h6> 131<a name="geometry.reference.algorithms.num_geometries.h5"></a> 132 <span class="phrase"><a name="geometry.reference.algorithms.num_geometries.conformance"></a></span><a class="link" href="num_geometries.html#geometry.reference.algorithms.num_geometries.conformance">Conformance</a> 133 </h6> 134<p> 135 The function num_geometries implements function NumGeometries from the 136 <a href="http://www.opengeospatial.org/standards/sfa" target="_top">OGC Simple Feature 137 Specification</a>. 138 </p> 139<h6> 140<a name="geometry.reference.algorithms.num_geometries.h6"></a> 141 <span class="phrase"><a name="geometry.reference.algorithms.num_geometries.behavior"></a></span><a class="link" href="num_geometries.html#geometry.reference.algorithms.num_geometries.behavior">Behavior</a> 142 </h6> 143<div class="informaltable"><table class="table"> 144<colgroup> 145<col> 146<col> 147</colgroup> 148<thead><tr> 149<th> 150 <p> 151 Case 152 </p> 153 </th> 154<th> 155 <p> 156 Behavior 157 </p> 158 </th> 159</tr></thead> 160<tbody> 161<tr> 162<td> 163 <p> 164 single (e.g. point, polygon) 165 </p> 166 </td> 167<td> 168 <p> 169 Returns 1 170 </p> 171 </td> 172</tr> 173<tr> 174<td> 175 <p> 176 multiple (e.g. multi_point, multi_polygon) 177 </p> 178 </td> 179<td> 180 <p> 181 Returns boost::size(geometry); the input is considered as a range 182 </p> 183 </td> 184</tr> 185</tbody> 186</table></div> 187<h6> 188<a name="geometry.reference.algorithms.num_geometries.h7"></a> 189 <span class="phrase"><a name="geometry.reference.algorithms.num_geometries.complexity"></a></span><a class="link" href="num_geometries.html#geometry.reference.algorithms.num_geometries.complexity">Complexity</a> 190 </h6> 191<p> 192 Constant 193 </p> 194<h6> 195<a name="geometry.reference.algorithms.num_geometries.h8"></a> 196 <span class="phrase"><a name="geometry.reference.algorithms.num_geometries.examples"></a></span><a class="link" href="num_geometries.html#geometry.reference.algorithms.num_geometries.examples">Examples</a> 197 </h6> 198<p> 199 Get the number of geometries making up a multi-geometry 200 </p> 201<p> 202</p> 203<pre class="programlisting"><span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">iostream</span><span class="special">></span> 204 205<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> 206<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> 207<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> 208<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">multi_polygon</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> 209 210 211<span class="keyword">int</span> <span class="identifier">main</span><span class="special">()</span> 212<span class="special">{</span> 213 <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">multi_polygon</span> 214 <span class="special"><</span> 215 <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> 216 <span class="special"><</span> 217 <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> 218 <span class="special">></span> 219 <span class="special">></span> <span class="identifier">mp</span><span class="special">;</span> 220 <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">"MULTIPOLYGON(((0 0,0 10,10 0,0 0),(1 1,1 9,9 1,1 1)),((10 10,10 7,7 10,10 10)))"</span><span class="special">,</span> <span class="identifier">mp</span><span class="special">);</span> 221 <span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special"><<</span> <span class="string">"Number of geometries: "</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">num_geometries</span><span class="special">(</span><span class="identifier">mp</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> 222 223 <span class="keyword">return</span> <span class="number">0</span><span class="special">;</span> 224<span class="special">}</span> 225</pre> 226<p> 227 </p> 228<p> 229 Output: 230 </p> 231<pre class="programlisting">Number of geometries: 2 232</pre> 233</div> 234<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> 235<td align="left"></td> 236<td align="right"><div class="copyright-footer">Copyright © 2009-2019 Barend Gehrels, Bruno Lalande, Mateusz Loskot, Adam 237 Wulkiewicz, Oracle and/or its affiliates<p> 238 Distributed under the Boost Software License, Version 1.0. (See accompanying 239 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>) 240 </p> 241</div></td> 242</tr></table> 243<hr> 244<div class="spirit-nav"> 245<a accesskey="p" href="make/make_zero.html"><img src="../../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../algorithms.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="num_interior_rings.html"><img src="../../../../../../../doc/src/images/next.png" alt="Next"></a> 246</div> 247</body> 248</html> 249
