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Predicates and DistancePredicates are stored by value in visitors. Each predicate is stored by value in expression tuple. Examples and docs updated. [SVN r83232]
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<div class="section">
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<div class="titlepage"><div><div><h3 class="title">
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<a name="geometry_index.r_tree.queries"></a><a class="link" href="queries.html" title="Queries">Queries</a>
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</h3></div></div></div>
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<div class="toc"><dl>
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<dt><span class="section"><a href="queries.html#geometry_index.r_tree.queries.performing_a_query">Performing
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a query</a></span></dt>
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<dt><span class="section"><a href="queries.html#geometry_index.r_tree.queries.spatial_queries">Spatial
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queries</a></span></dt>
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<dt><span class="section"><a href="queries.html#geometry_index.r_tree.queries.nearest_neighbours_queries">Nearest
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neighbours queries</a></span></dt>
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<dt><span class="section"><a href="queries.html#geometry_index.r_tree.queries.user_defined_unary_predicate">user-defined
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unary predicate</a></span></dt>
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<dt><span class="section"><a href="queries.html#geometry_index.r_tree.queries.passing_a_set_of_predicates">Passing
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a set of predicates</a></span></dt>
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<dt><span class="section"><a href="queries.html#geometry_index.r_tree.queries.inserting_query_results_into_the_other_r_tree">Inserting
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query results into the other R-tree</a></span></dt>
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</dl></div>
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<p>
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Queries returns <code class="computeroutput">Value</code>s which meets some predicates. Currently
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supported are three types of predicates:
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</p>
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<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
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<li class="listitem">
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spatial predicates - defining relationship between stored Values and
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some Geometry,
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</li>
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<li class="listitem">
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nearest predicate - defining relationship between stored Values and some
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Point,
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</li>
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<li class="listitem">
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user-defined unary predicate - function, function object or lambda expression
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checking user-defined condition.
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</li>
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</ul></div>
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<p>
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For example queries may be used to retrieve Values:
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</p>
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<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
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<li class="listitem">
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intersecting some area but not within other area,
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</li>
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<li class="listitem">
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are nearest to some point,
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</li>
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<li class="listitem">
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overlapping a box and has user-defined property.
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</li>
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</ul></div>
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<div class="section">
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<div class="titlepage"><div><div><h4 class="title">
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<a name="geometry_index.r_tree.queries.performing_a_query"></a><a class="link" href="queries.html#geometry_index.r_tree.queries.performing_a_query" title="Performing a query">Performing
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a query</a>
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</h4></div></div></div>
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<p>
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There are three ways to perform a query presented below. All of them returns
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<code class="computeroutput">Value</code>s intersecting some region defined as a <code class="computeroutput"><a href="http://www.boost.org/libs/geometry/doc/html/geometry/reference/concepts/concept_box.html" target="_top">Box</a></code>.
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</p>
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<p>
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Method call
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</p>
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<pre class="programlisting"><span class="identifier">std</span><span class="special">::</span><span class="identifier">vector</span><span class="special"><</span>Value<span class="special">></span> <span class="identifier">returned_values</span><span class="special">;</span>
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<a href="http://www.boost.org/libs/geometry/doc/html/geometry/reference/concepts/concept_box.html" target="_top">Box</a> <span class="identifier">box_region</span><span class="special">(...);</span>
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<span class="identifier">rt</span><span class="special">.</span><span class="identifier">query</span><span class="special">(</span><span class="identifier">bgi</span><span class="special">::</span><span class="identifier">intersects</span><span class="special">(</span><span class="identifier">box_region</span><span class="special">),</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">back_inserter</span><span class="special">(</span><span class="identifier">returned_values</span><span class="special">));</span>
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</pre>
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<p>
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Function call
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</p>
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<pre class="programlisting"><span class="identifier">std</span><span class="special">::</span><span class="identifier">vector</span><span class="special"><</span>Value<span class="special">></span> <span class="identifier">returned_values</span><span class="special">;</span>
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<a href="http://www.boost.org/libs/geometry/doc/html/geometry/reference/concepts/concept_box.html" target="_top">Box</a> <span class="identifier">box_region</span><span class="special">(...);</span>
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<span class="identifier">index</span><span class="special">::</span><span class="identifier">query</span><span class="special">(</span><span class="identifier">rt</span><span class="special">,</span> <span class="identifier">bgi</span><span class="special">::</span><span class="identifier">intersects</span><span class="special">(</span><span class="identifier">box_region</span><span class="special">),</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">back_inserter</span><span class="special">(</span><span class="identifier">returned_values</span><span class="special">));</span>
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</pre>
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<p>
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Use of pipe operator generating a range
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</p>
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<pre class="programlisting"><a href="http://www.boost.org/libs/geometry/doc/html/geometry/reference/concepts/concept_box.html" target="_top">Box</a> <span class="identifier">box_region</span><span class="special">(...);</span>
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<span class="identifier">BOOST_FOREACH</span><span class="special">(</span>Value <span class="special">&</span> <span class="identifier">v</span><span class="special">,</span> <span class="identifier">rt</span> <span class="special">|</span> <span class="identifier">index</span><span class="special">::</span><span class="identifier">adaptors</span><span class="special">::</span><span class="identifier">queried</span><span class="special">(</span><span class="identifier">bgi</span><span class="special">::</span><span class="identifier">intersects</span><span class="special">(</span><span class="identifier">box_region</span><span class="special">)))</span>
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<span class="special">;</span> <span class="comment">// do something with v</span>
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</pre>
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</div>
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<div class="section">
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<div class="titlepage"><div><div><h4 class="title">
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<a name="geometry_index.r_tree.queries.spatial_queries"></a><a class="link" href="queries.html#geometry_index.r_tree.queries.spatial_queries" title="Spatial queries">Spatial
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queries</a>
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</h4></div></div></div>
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<p>
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Spatial query returns <code class="computeroutput">Value</code>s which are related somehow to
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some Geometry - box, polygon, etc. Names of spatial predicates corresponds
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to names of <a href="http://www.boost.org/libs/geometry/doc/html/index.html" target="_top">Boost.Geometry</a>
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algorithms. Examples of some basic queries may be found in tables below.
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The query region and result <code class="computeroutput"><span class="identifier">Value</span></code>s
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are orange.
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</p>
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<div class="informaltable"><table class="table">
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<colgroup>
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<col>
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<col>
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<col>
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<col>
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<col>
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</colgroup>
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<thead><tr>
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<th>
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<p>
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intersects(Box) - default
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</p>
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</th>
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<th>
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<p>
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covered_by(Box)
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</p>
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</th>
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<th>
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<p>
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disjoint(Box)
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</p>
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</th>
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<th>
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<p>
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overlaps(Box)
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</p>
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</th>
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<th>
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<p>
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within(Box)
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</p>
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</th>
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</tr></thead>
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<tbody><tr>
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<td>
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<p>
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<span class="inlinemediaobject"><img src="../../../images/intersects.png" alt="intersects"></span>
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</p>
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</td>
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<td>
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<p>
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<span class="inlinemediaobject"><img src="../../../images/within.png" alt="within"></span>
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</p>
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</td>
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<td>
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<p>
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<span class="inlinemediaobject"><img src="../../../images/disjoint.png" alt="disjoint"></span>
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</p>
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</td>
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<td>
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<p>
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<span class="inlinemediaobject"><img src="../../../images/overlaps.png" alt="overlaps"></span>
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</p>
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</td>
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<td>
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<p>
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<span class="inlinemediaobject"><img src="../../../images/within.png" alt="within"></span>
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</p>
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</td>
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</tr></tbody>
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</table></div>
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<div class="informaltable"><table class="table">
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<colgroup>
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<col>
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<col>
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<col>
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</colgroup>
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<thead><tr>
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<th>
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<p>
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intersects(Ring)
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</p>
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</th>
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<th>
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<p>
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intersects(Polygon)
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</p>
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</th>
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<th>
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<p>
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intersects(MultiPolygon)
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</p>
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</th>
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</tr></thead>
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<tbody><tr>
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<td>
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<p>
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<span class="inlinemediaobject"><img src="../../../images/intersects_ring.png" alt="intersects_ring"></span>
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</p>
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</td>
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<td>
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<p>
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<span class="inlinemediaobject"><img src="../../../images/intersects_poly.png" alt="intersects_poly"></span>
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</p>
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</td>
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<td>
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<p>
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<span class="inlinemediaobject"><img src="../../../images/intersects_mpoly.png" alt="intersects_mpoly"></span>
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</p>
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</td>
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</tr></tbody>
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</table></div>
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<p>
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To use a spatial predicate one may use one of the functions defined in
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<code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">geometry</span><span class="special">::</span><span class="identifier">index</span></code> namespace.
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</p>
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<pre class="programlisting"><span class="identifier">rt</span><span class="special">.</span><span class="identifier">query</span><span class="special">(</span><span class="identifier">index</span><span class="special">::</span><span class="identifier">intersects</span><span class="special">(</span><span class="identifier">box</span><span class="special">),</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">back_inserter</span><span class="special">(</span><span class="identifier">result</span><span class="special">));</span>
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<span class="identifier">rt</span><span class="special">.</span><span class="identifier">query</span><span class="special">(</span><span class="identifier">index</span><span class="special">::</span><span class="identifier">covered_by</span><span class="special">(</span><span class="identifier">box</span><span class="special">),</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">back_inserter</span><span class="special">(</span><span class="identifier">result</span><span class="special">));</span>
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<span class="identifier">rt</span><span class="special">.</span><span class="identifier">query</span><span class="special">(</span><span class="identifier">index</span><span class="special">::</span><span class="identifier">disjont</span><span class="special">(</span><span class="identifier">box</span><span class="special">),</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">back_inserter</span><span class="special">(</span><span class="identifier">result</span><span class="special">));</span>
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<span class="identifier">rt</span><span class="special">.</span><span class="identifier">query</span><span class="special">(</span><span class="identifier">index</span><span class="special">::</span><span class="identifier">overlaps</span><span class="special">(</span><span class="identifier">box</span><span class="special">),</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">back_inserter</span><span class="special">(</span><span class="identifier">result</span><span class="special">));</span>
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<span class="identifier">rt</span><span class="special">.</span><span class="identifier">query</span><span class="special">(</span><span class="identifier">index</span><span class="special">::</span><span class="identifier">within</span><span class="special">(</span><span class="identifier">box</span><span class="special">),</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">back_inserter</span><span class="special">(</span><span class="identifier">result</span><span class="special">));</span>
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</pre>
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<p>
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All predicates may be negated, e.g.:
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</p>
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<pre class="programlisting"><span class="identifier">rt</span><span class="special">.</span><span class="identifier">query</span><span class="special">(!</span><span class="identifier">index</span><span class="special">::</span><span class="identifier">intersects</span><span class="special">(</span><span class="identifier">box</span><span class="special">),</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">back_inserter</span><span class="special">(</span><span class="identifier">result</span><span class="special">));</span>
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<span class="comment">// the same as</span>
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<span class="identifier">rt</span><span class="special">.</span><span class="identifier">query</span><span class="special">(</span><span class="identifier">index</span><span class="special">::</span><span class="identifier">disjoint</span><span class="special">(</span><span class="identifier">box</span><span class="special">),</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">back_inserter</span><span class="special">(</span><span class="identifier">result</span><span class="special">));</span>
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</pre>
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</div>
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<div class="section">
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<div class="titlepage"><div><div><h4 class="title">
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<a name="geometry_index.r_tree.queries.nearest_neighbours_queries"></a><a class="link" href="queries.html#geometry_index.r_tree.queries.nearest_neighbours_queries" title="Nearest neighbours queries">Nearest
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neighbours queries</a>
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</h4></div></div></div>
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<p>
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Nearest neighbours queries returns <code class="computeroutput">Value</code>s which are closest
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to some point in space. Additionally it is possible to define how the distance
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to the <code class="computeroutput"><span class="identifier">Value</span></code> should be
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calculated. The examples of some knn queries may be found in the table
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below. All queries return 5 closest <code class="computeroutput"><span class="identifier">Values</span></code>.
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The query point and Values are orange.
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</p>
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<p>
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<span class="inlinemediaobject"><img src="../../../images/knn.png" alt="knn"></span>
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</p>
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<div class="section">
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<div class="titlepage"><div><div><h5 class="title">
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<a name="geometry_index.r_tree.queries.nearest_neighbours_queries.k_nearest_neighbours"></a><a class="link" href="queries.html#geometry_index.r_tree.queries.nearest_neighbours_queries.k_nearest_neighbours" title="k nearest neighbours">k
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nearest neighbours</a>
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</h5></div></div></div>
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<p>
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There are three ways of performing knn queries. Following queries returns
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<code class="computeroutput"><span class="identifier">k</span></code> <code class="computeroutput">Value</code>s
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closest to some point in space. For <code class="computeroutput"><a href="http://www.boost.org/libs/geometry/doc/html/geometry/reference/concepts/concept_box.html" target="_top">Box</a></code>es
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<code class="computeroutput">Indexable</code>s the distance to the nearest point is calculated
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by default.
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</p>
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<p>
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Method call
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</p>
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<pre class="programlisting"><span class="identifier">std</span><span class="special">::</span><span class="identifier">vector</span><span class="special"><</span>Value<span class="special">></span> <span class="identifier">returned_values</span><span class="special">;</span>
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<a href="http://www.boost.org/libs/geometry/doc/html/geometry/reference/concepts/concept_point.html" target="_top">Point</a> <span class="identifier">pt</span><span class="special">(...);</span>
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<span class="identifier">rt</span><span class="special">.</span><span class="identifier">query</span><span class="special">(</span><span class="identifier">index</span><span class="special">::</span><span class="identifier">nearest</span><span class="special">(</span><span class="identifier">pt</span><span class="special">,</span> <span class="identifier">k</span><span class="special">),</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">back_inserter</span><span class="special">(</span><span class="identifier">returned_values</span><span class="special">));</span>
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</pre>
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<p>
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Function call
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</p>
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<pre class="programlisting"><span class="identifier">std</span><span class="special">::</span><span class="identifier">vector</span><span class="special"><</span>Value<span class="special">></span> <span class="identifier">returned_values</span><span class="special">;</span>
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<a href="http://www.boost.org/libs/geometry/doc/html/geometry/reference/concepts/concept_point.html" target="_top">Point</a> <span class="identifier">pt</span><span class="special">(...);</span>
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<span class="identifier">index</span><span class="special">::</span><span class="identifier">query</span><span class="special">(</span><span class="identifier">rt</span><span class="special">,</span> <span class="identifier">index</span><span class="special">::</span><span class="identifier">nearest</span><span class="special">(</span><span class="identifier">pt</span><span class="special">,</span> <span class="identifier">k</span><span class="special">),</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">back_inserter</span><span class="special">(</span><span class="identifier">returned_values</span><span class="special">));</span>
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</pre>
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<p>
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Use of <code class="computeroutput"><span class="keyword">operator</span> <span class="special">|</span></code>
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</p>
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<pre class="programlisting"><a href="http://www.boost.org/libs/geometry/doc/html/geometry/reference/concepts/concept_point.html" target="_top">Point</a> <span class="identifier">pt</span><span class="special">(...);</span>
|
|
<span class="identifier">BOOST_FOREACH</span><span class="special">(</span>Value <span class="special">&</span> <span class="identifier">v</span><span class="special">,</span> <span class="identifier">rt</span> <span class="special">|</span> <span class="identifier">index</span><span class="special">::</span><span class="identifier">adaptors</span><span class="special">::</span><span class="identifier">queried</span><span class="special">(</span><span class="identifier">index</span><span class="special">::</span><span class="identifier">nearest</span><span class="special">(</span><span class="identifier">pt</span><span class="special">,</span> <span class="identifier">k</span><span class="special">)))</span>
|
|
<span class="special">;</span> <span class="comment">// do something with v</span>
|
|
</pre>
|
|
</div>
|
|
<div class="section">
|
|
<div class="titlepage"><div><div><h5 class="title">
|
|
<a name="geometry_index.r_tree.queries.nearest_neighbours_queries.distance_calculation"></a><a class="link" href="queries.html#geometry_index.r_tree.queries.nearest_neighbours_queries.distance_calculation" title="Distance calculation">Distance
|
|
calculation</a>
|
|
</h5></div></div></div>
|
|
<p>
|
|
It is possible to define how distance to the non-point <code class="computeroutput">Value</code>
|
|
should be calculated. To do this one may pass a relation object generated
|
|
as follows:
|
|
</p>
|
|
<pre class="programlisting"><span class="comment">/* caluclate distance to the Indexables' nearest points */</span>
|
|
<span class="identifier">tree</span><span class="special">::</span><span class="identifier">query</span><span class="special">(</span><span class="identifier">index</span><span class="special">::</span><span class="identifier">nearest</span><span class="special">(</span><span class="identifier">index</span><span class="special">::</span><span class="identifier">to_nearest</span><span class="special">(</span><span class="identifier">pt</span><span class="special">),</span> <span class="identifier">k</span><span class="special">),</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">back_inserter</span><span class="special">(</span><span class="identifier">returned_values</span><span class="special">));</span> <span class="comment">// default</span>
|
|
<span class="comment">/* caluclate distance to the Indexables' centroid */</span>
|
|
<span class="identifier">tree</span><span class="special">::</span><span class="identifier">query</span><span class="special">(</span><span class="identifier">index</span><span class="special">::</span><span class="identifier">nearest</span><span class="special">(</span><span class="identifier">index</span><span class="special">::</span><span class="identifier">to_centroid</span><span class="special">(</span><span class="identifier">pt</span><span class="special">),</span> <span class="identifier">k</span><span class="special">),</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">back_inserter</span><span class="special">(</span><span class="identifier">returned_values</span><span class="special">));</span>
|
|
<span class="comment">/* caluclate distance to the Indexables' furthest points */</span>
|
|
<span class="identifier">tree</span><span class="special">::</span><span class="identifier">query</span><span class="special">(</span><span class="identifier">index</span><span class="special">::</span><span class="identifier">nearest</span><span class="special">(</span><span class="identifier">index</span><span class="special">::</span><span class="identifier">to_furthest</span><span class="special">(</span><span class="identifier">pt</span><span class="special">),</span> <span class="identifier">k</span><span class="special">),</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">back_inserter</span><span class="special">(</span><span class="identifier">returned_values</span><span class="special">));</span>
|
|
</pre>
|
|
</div>
|
|
</div>
|
|
<div class="section">
|
|
<div class="titlepage"><div><div><h4 class="title">
|
|
<a name="geometry_index.r_tree.queries.user_defined_unary_predicate"></a><a class="link" href="queries.html#geometry_index.r_tree.queries.user_defined_unary_predicate" title="user-defined unary predicate">user-defined
|
|
unary predicate</a>
|
|
</h4></div></div></div>
|
|
<p>
|
|
The user may pass a <code class="computeroutput"><span class="identifier">UnaryPredicate</span></code>
|
|
- function, function object or lambda expression taking const reference
|
|
to Value and returning bool. This object may be passed to the query in
|
|
order to check if <code class="computeroutput">Value</code> should be returned by the query. To
|
|
do it one may use <code class="computeroutput"><span class="identifier">index</span><span class="special">::</span><span class="identifier">satisfies</span><span class="special">()</span></code> function like on the example below:
|
|
</p>
|
|
<pre class="programlisting"><span class="keyword">bool</span> <span class="identifier">is_red</span><span class="special">(</span>Value <span class="keyword">const</span><span class="special">&</span> <span class="identifier">v</span><span class="special">)</span>
|
|
<span class="special">{</span>
|
|
<span class="keyword">return</span> <span class="identifier">v</span><span class="special">.</span><span class="identifier">is_red</span><span class="special">();</span>
|
|
<span class="special">}</span>
|
|
|
|
<span class="keyword">struct</span> <span class="identifier">is_red_o</span>
|
|
<span class="special">{</span>
|
|
<span class="keyword">template</span> <span class="special"><</span><span class="keyword">typename</span> <span class="identifier">Value</span><span class="special">></span>
|
|
<span class="keyword">bool</span> <span class="keyword">operator</span><span class="special">()(</span>Value <span class="keyword">const</span><span class="special">&</span> <span class="identifier">v</span><span class="special">)</span>
|
|
<span class="special">{</span>
|
|
<span class="keyword">return</span> <span class="identifier">v</span><span class="special">.</span><span class="identifier">is_red</span><span class="special">();</span>
|
|
<span class="special">}</span>
|
|
<span class="special">}</span>
|
|
|
|
<span class="comment">// ...</span>
|
|
|
|
<span class="identifier">rt</span><span class="special">.</span><span class="identifier">query</span><span class="special">(</span><span class="identifier">index</span><span class="special">::</span><span class="identifier">intersects</span><span class="special">(</span><span class="identifier">box</span><span class="special">)</span> <span class="special">&&</span> <span class="identifier">index</span><span class="special">::</span><span class="identifier">satisfies</span><span class="special">(</span><span class="identifier">is_red</span><span class="special">),</span>
|
|
<span class="identifier">std</span><span class="special">::</span><span class="identifier">back_inserter</span><span class="special">(</span><span class="identifier">result</span><span class="special">));</span>
|
|
|
|
<span class="identifier">rt</span><span class="special">.</span><span class="identifier">query</span><span class="special">(</span><span class="identifier">index</span><span class="special">::</span><span class="identifier">intersects</span><span class="special">(</span><span class="identifier">box</span><span class="special">)</span> <span class="special">&&</span> <span class="identifier">index</span><span class="special">::</span><span class="identifier">satisfies</span><span class="special">(</span><span class="identifier">is_red_o</span><span class="special">()),</span>
|
|
<span class="identifier">std</span><span class="special">::</span><span class="identifier">back_inserter</span><span class="special">(</span><span class="identifier">result</span><span class="special">));</span>
|
|
|
|
<span class="preprocessor">#ifndef</span> <span class="identifier">BOOST_NO_CXX11_LAMBDAS</span>
|
|
<span class="identifier">rt</span><span class="special">.</span><span class="identifier">query</span><span class="special">(</span><span class="identifier">index</span><span class="special">::</span><span class="identifier">intersects</span><span class="special">(</span><span class="identifier">box</span><span class="special">)</span> <span class="special">&&</span> <span class="identifier">index</span><span class="special">::</span><span class="identifier">satisfies</span><span class="special">([](</span>Value <span class="keyword">const</span><span class="special">&</span> <span class="identifier">v</span><span class="special">)</span> <span class="special">{</span> <span class="keyword">return</span> <span class="identifier">v</span><span class="special">.</span><span class="identifier">is_red</span><span class="special">();</span> <span class="special">}),</span>
|
|
<span class="identifier">std</span><span class="special">::</span><span class="identifier">back_inserter</span><span class="special">(</span><span class="identifier">result</span><span class="special">));</span>
|
|
<span class="preprocessor">#endif</span>
|
|
</pre>
|
|
</div>
|
|
<div class="section">
|
|
<div class="titlepage"><div><div><h4 class="title">
|
|
<a name="geometry_index.r_tree.queries.passing_a_set_of_predicates"></a><a class="link" href="queries.html#geometry_index.r_tree.queries.passing_a_set_of_predicates" title="Passing a set of predicates">Passing
|
|
a set of predicates</a>
|
|
</h4></div></div></div>
|
|
<p>
|
|
It's possible to use some number of predicates in one query by connecting
|
|
them with <code class="computeroutput"><span class="keyword">operator</span><span class="special">&&</span></code>
|
|
e.g. <code class="computeroutput"><span class="identifier">Pred1</span> <span class="special">&&</span>
|
|
<span class="identifier">Pred2</span> <span class="special">&&</span>
|
|
<span class="identifier">Pred3</span> <span class="special">&&</span>
|
|
<span class="special">...</span></code>.
|
|
</p>
|
|
<p>
|
|
These predicates are connected by logical AND. Passing all predicates together
|
|
not only makes possible to construct advanced queries but is also faster
|
|
than separate calls because the tree is traversed only once. Traversing
|
|
is continued and <code class="computeroutput"><span class="identifier">Value</span></code>s
|
|
are returned only if all predicates are met. Predicates are checked left-to-right
|
|
so placing most restictive predicates first should accelerate the search.
|
|
</p>
|
|
<pre class="programlisting"><span class="identifier">rt</span><span class="special">.</span><span class="identifier">query</span><span class="special">(</span><span class="identifier">index</span><span class="special">::</span><span class="identifier">intersects</span><span class="special">(</span><span class="identifier">box1</span><span class="special">)</span> <span class="special">&&</span> <span class="special">!</span><span class="identifier">index</span><span class="special">::</span><span class="identifier">within</span><span class="special">(</span><span class="identifier">box2</span><span class="special">),</span>
|
|
<span class="identifier">std</span><span class="special">::</span><span class="identifier">back_inserter</span><span class="special">(</span><span class="identifier">result</span><span class="special">));</span>
|
|
|
|
<span class="identifier">rt</span><span class="special">.</span><span class="identifier">query</span><span class="special">(</span><span class="identifier">index</span><span class="special">::</span><span class="identifier">intersects</span><span class="special">(</span><span class="identifier">box1</span><span class="special">)</span> <span class="special">&&</span> <span class="special">!</span><span class="identifier">index</span><span class="special">::</span><span class="identifier">within</span><span class="special">(</span><span class="identifier">box2</span><span class="special">)</span> <span class="special">&&</span> <span class="identifier">index</span><span class="special">::</span><span class="identifier">overlaps</span><span class="special">(</span><span class="identifier">box3</span><span class="special">),</span>
|
|
<span class="identifier">std</span><span class="special">::</span><span class="identifier">back_inserter</span><span class="special">(</span><span class="identifier">result</span><span class="special">));</span>
|
|
</pre>
|
|
<p>
|
|
Of course it's possible to connect different types of predicates together.
|
|
</p>
|
|
<pre class="programlisting"><span class="identifier">index</span><span class="special">::</span><span class="identifier">query</span><span class="special">(</span><span class="identifier">rt</span><span class="special">,</span> <span class="identifier">index</span><span class="special">::</span><span class="identifier">nearest</span><span class="special">(</span><span class="identifier">pt</span><span class="special">,</span> <span class="identifier">k</span><span class="special">)</span> <span class="special">&&</span> <span class="identifier">index</span><span class="special">::</span><span class="identifier">within</span><span class="special">(</span><span class="identifier">b</span><span class="special">),</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">back_inserter</span><span class="special">(</span><span class="identifier">returned_values</span><span class="special">));</span>
|
|
|
|
<span class="identifier">BOOST_FOREACH</span><span class="special">(</span><span class="identifier">Value</span> <span class="special">&</span> <span class="identifier">v</span><span class="special">,</span> <span class="identifier">rt</span> <span class="special">|</span> <span class="identifier">index</span><span class="special">::</span><span class="identifier">adaptors</span><span class="special">::</span><span class="identifier">queried</span><span class="special">(</span><span class="identifier">index</span><span class="special">::</span><span class="identifier">nearest</span><span class="special">(</span><span class="identifier">pt</span><span class="special">,</span> <span class="identifier">k</span><span class="special">)</span> <span class="special">&&</span> <span class="identifier">index</span><span class="special">::</span><span class="identifier">covered_by</span><span class="special">(</span><span class="identifier">b</span><span class="special">)))</span>
|
|
<span class="special">;</span> <span class="comment">// do something with v</span>
|
|
</pre>
|
|
</div>
|
|
<div class="section">
|
|
<div class="titlepage"><div><div><h4 class="title">
|
|
<a name="geometry_index.r_tree.queries.inserting_query_results_into_the_other_r_tree"></a><a class="link" href="queries.html#geometry_index.r_tree.queries.inserting_query_results_into_the_other_r_tree" title="Inserting query results into the other R-tree">Inserting
|
|
query results into the other R-tree</a>
|
|
</h4></div></div></div>
|
|
<p>
|
|
There are several ways of inserting Values returned by a query to the other
|
|
R-tree container. The most basic way is creating a temporary container
|
|
for Values and insert them later.
|
|
</p>
|
|
<pre class="programlisting"><span class="keyword">namespace</span> <span class="identifier">bgi</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">index</span><span class="special">;</span>
|
|
<span class="keyword">typedef</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">pair</span><span class="special"><</span><span class="identifier">Box</span><span class="special">,</span> <span class="keyword">int</span><span class="special">></span> Value<span class="special">;</span>
|
|
<span class="keyword">typedef</span> <span class="identifier">bgi</span><span class="special">::</span><span class="identifier">rtree</span><span class="special"><</span> Value<span class="special">,</span> <span class="identifier">bgi</span><span class="special">::</span><span class="identifier">linear</span><span class="special"><</span><span class="number">32</span><span class="special">,</span> <span class="number">8</span><span class="special">></span> <span class="special">></span> <span class="identifier">RTree</span><span class="special">;</span>
|
|
|
|
<span class="identifier">RTree</span> <span class="identifier">rt1</span><span class="special">;</span>
|
|
<span class="comment">/* some inserting into the tree */</span>
|
|
|
|
<span class="identifier">std</span><span class="special">::</span><span class="identifier">vector</span><span class="special"><</span><span class="identifier">Value</span><span class="special">></span> <span class="identifier">result</span><span class="special">;</span>
|
|
<span class="identifier">rt1</span><span class="special">.</span><span class="identifier">query</span><span class="special">(</span><span class="identifier">bgi</span><span class="special">::</span><span class="identifier">intersects</span><span class="special">(</span><span class="identifier">Box</span><span class="special">(/*...*/)),</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">back_inserter</span><span class="special">(</span><span class="identifier">result</span><span class="special">));</span>
|
|
<span class="identifier">RTree</span> <span class="identifier">rt2</span><span class="special">(</span><span class="identifier">result</span><span class="special">.</span><span class="identifier">begin</span><span class="special">(),</span> <span class="identifier">result</span><span class="special">.</span><span class="identifier">end</span><span class="special">());</span>
|
|
</pre>
|
|
<p>
|
|
However there are better ways. One of these methods is mentioned in the
|
|
"Creation and modification" section. The insert iterator may
|
|
be passed directly to the query, which will be the fastest way of inserting
|
|
query results because temporary container won't be used.
|
|
</p>
|
|
<pre class="programlisting"><span class="identifier">RTree</span> <span class="identifier">rt3</span><span class="special">;</span>
|
|
<span class="identifier">rt1</span><span class="special">.</span><span class="identifier">query</span><span class="special">(</span><span class="identifier">bgi</span><span class="special">::</span><span class="identifier">intersects</span><span class="special">(</span><span class="identifier">Box</span><span class="special">(/*...*/))),</span> <span class="identifier">bgi</span><span class="special">::</span><span class="identifier">inserter</span><span class="special">(</span><span class="identifier">rt3</span><span class="special">));</span>
|
|
</pre>
|
|
<p>
|
|
If you like Boost.Range you'll appreciate the third option. You may pass
|
|
the result Range directly to the constructor. However in this case the
|
|
temporary container is created.
|
|
</p>
|
|
<pre class="programlisting"><span class="identifier">RTree</span> <span class="identifier">rt4</span><span class="special">(</span><span class="identifier">rt1</span> <span class="special">|</span> <span class="identifier">bgi</span><span class="special">::</span><span class="identifier">adaptors</span><span class="special">::</span><span class="identifier">queried</span><span class="special">(</span><span class="identifier">bgi</span><span class="special">::</span><span class="identifier">intersects</span><span class="special">(</span><span class="identifier">Box</span><span class="special">(/*...*/)))));</span>
|
|
</pre>
|
|
</div>
|
|
</div>
|
|
<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
|
|
<td align="left"></td>
|
|
<td align="right"><div class="copyright-footer">Copyright © 2011-2013 Adam Wulkiewicz<p>
|
|
Distributed under the Boost Software License, Version 1.0. (See accompanying
|
|
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>)
|
|
</p>
|
|
</div></td>
|
|
</tr></table>
|
|
<hr>
|
|
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