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<meta property="og:title" content="Inhomogeneous O-ring — o.ring" />
<meta property="og:description" content="Calculates the inhomogeneous O-ring point pattern statistic 
            (Wiegand &amp;amp; Maloney 2004)
The function K(r) is the expected number of points in a circle of radius r centered 
at an arbitrary point (which is not counted), divided by the intensity l of the pattern. 
The alternative pair correlation function g(r), which arises if the circles of 
Ripley's K-function are replaced by rings, gives the expected number of points at 
distance r from an arbitrary point, divided by the intensity of the pattern. Of special 
interest is to determine whether a pattern is random, clumped, or regular.
Using rings instead of circles has the advantage that one can isolate specific 
distance classes, whereas the cumulative K-function confounds effects at larger 
distances with effects at shorter distances. Note that the K-function and the O-ring 
statistic respond to slightly different biological questions. The accumulative 
K-function can detect aggregation or dispersion up to a given distance r and is 
therefore appropriate if the process in question (e.g., the negative effect of 
competition) may work only up to a certain distance, whereas the O-ring statistic 
can detect aggregation or dispersion at a given distance r. The O-ring statistic 
has the additional advantage that it is a probability density function (or a 
conditioned probability spectrum) with the interpretation of a neighborhood 
density, which is more intuitive than an accumulative measure." />




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    <h1>Inhomogeneous O-ring</h1>
    <small class="dont-index">Source: <a href='https://github.com/jeffreyevans/spatialEco/blob/master/R/o.ring.R'><code>R/o.ring.R</code></a></small>
    <div class="hidden name"><code>o.ring.Rd</code></div>
    </div>

    <div class="ref-description">
    <p>Calculates the inhomogeneous O-ring point pattern statistic 
            (Wiegand &amp; Maloney 2004)</p>
<p>The function K(r) is the expected number of points in a circle of radius r centered 
at an arbitrary point (which is not counted), divided by the intensity l of the pattern. 
The alternative pair correlation function g(r), which arises if the circles of 
Ripley's K-function are replaced by rings, gives the expected number of points at 
distance r from an arbitrary point, divided by the intensity of the pattern. Of special 
interest is to determine whether a pattern is random, clumped, or regular.</p>
<p>Using rings instead of circles has the advantage that one can isolate specific 
distance classes, whereas the cumulative K-function confounds effects at larger 
distances with effects at shorter distances. Note that the K-function and the O-ring 
statistic respond to slightly different biological questions. The accumulative 
K-function can detect aggregation or dispersion up to a given distance r and is 
therefore appropriate if the process in question (e.g., the negative effect of 
competition) may work only up to a certain distance, whereas the O-ring statistic 
can detect aggregation or dispersion at a given distance r. The O-ring statistic 
has the additional advantage that it is a probability density function (or a 
conditioned probability spectrum) with the interpretation of a neighborhood 
density, which is more intuitive than an accumulative measure.</p>
    </div>

    <pre class="usage"><span class='fu'>o.ring</span><span class='op'>(</span><span class='va'>x</span>, inhomogeneous <span class='op'>=</span> <span class='cn'>FALSE</span>, <span class='va'>...</span><span class='op'>)</span></pre>

    <h2 class="hasAnchor" id="arguments"><a class="anchor" href="#arguments"></a>Arguments</h2>
    <table class="ref-arguments">
    <colgroup><col class="name" /><col class="desc" /></colgroup>
    <tr>
      <th>x</th>
      <td><p>spatstat ppp object</p></td>
    </tr>
    <tr>
      <th>inhomogeneous</th>
      <td><p>(FALSE/TRUE) Run homogeneous (pcf) or inhomogeneous 
(pcfinhom)</p></td>
    </tr>
    <tr>
      <th>...</th>
      <td><p>additional arguments passed to pcf or pcfinhom</p></td>
    </tr>
    </table>

    <h2 class="hasAnchor" id="value"><a class="anchor" href="#value"></a>Value</h2>

    <p>plot of o-ring and data.frame with plot labels and descriptions</p>
    <h2 class="hasAnchor" id="references"><a class="anchor" href="#references"></a>References</h2>

    <p>Wiegand T., and K. A. Moloney (2004) Rings, circles and null-models for point 
pattern analysis in ecology. Oikos 104:209-229</p>
    <h2 class="hasAnchor" id="author"><a class="anchor" href="#author"></a>Author</h2>

    <p>Jeffrey S. Evans  &lt;jeffrey_evans@tnc.org&gt;</p>

    <h2 class="hasAnchor" id="examples"><a class="anchor" href="#examples"></a>Examples</h2>
    <pre class="examples"><div class='input'><span class='kw'><a href='https://rdrr.io/r/base/library.html'>library</a></span><span class='op'>(</span><span class='va'><a href='http://spatstat.org/'>spatstat.core</a></span><span class='op'>)</span> 
</div><div class='output co'>#&gt; <span class='message'>Loading required package: spatstat.data</span></div><div class='output co'>#&gt; <span class='message'></span>
#&gt; <span class='message'>Attaching package: 'spatstat.data'</span></div><div class='output co'>#&gt; <span class='message'>The following object is masked from 'package:spatialEco':</span>
#&gt; <span class='message'></span>
#&gt; <span class='message'>    ants</span></div><div class='output co'>#&gt; <span class='message'>Loading required package: spatstat.geom</span></div><div class='output co'>#&gt; <span class='message'>spatstat.geom 2.1-0</span></div><div class='output co'>#&gt; <span class='message'></span>
#&gt; <span class='message'>Attaching package: 'spatstat.geom'</span></div><div class='output co'>#&gt; <span class='message'>The following object is masked from 'package:rms':</span>
#&gt; <span class='message'></span>
#&gt; <span class='message'>    perimeter</span></div><div class='output co'>#&gt; <span class='message'>The following objects are masked from 'package:raster':</span>
#&gt; <span class='message'></span>
#&gt; <span class='message'>    area, rotate, shift</span></div><div class='output co'>#&gt; <span class='message'>The following objects are masked from 'package:spatialEco':</span>
#&gt; <span class='message'></span>
#&gt; <span class='message'>    is.empty, quadrats, shift</span></div><div class='output co'>#&gt; <span class='message'>Loading required package: nlme</span></div><div class='output co'>#&gt; <span class='message'></span>
#&gt; <span class='message'>Attaching package: 'nlme'</span></div><div class='output co'>#&gt; <span class='message'>The following object is masked from 'package:raster':</span>
#&gt; <span class='message'></span>
#&gt; <span class='message'>    getData</span></div><div class='output co'>#&gt; <span class='message'>Loading required package: rpart</span></div><div class='output co'>#&gt; <span class='message'>spatstat.core 2.1-2</span></div><div class='output co'>#&gt; <span class='message'></span>
#&gt; <span class='message'>Attaching package: 'spatstat.core'</span></div><div class='output co'>#&gt; <span class='message'>The following object is masked from 'package:lattice':</span>
#&gt; <span class='message'></span>
#&gt; <span class='message'>    panel.histogram</span></div><div class='input'><span class='fu'><a href='https://rdrr.io/r/utils/data.html'>data</a></span><span class='op'>(</span><span class='va'>lansing</span><span class='op'>)</span>
    <span class='va'>x</span>  <span class='op'>&lt;-</span> <span class='fu'>spatstat.geom</span><span class='fu'>::</span><span class='fu'><a href='https://rdrr.io/pkg/spatstat.geom/man/unmark.html'>unmark</a></span><span class='op'>(</span><span class='fu'><a href='https://rdrr.io/r/base/split.html'>split</a></span><span class='op'>(</span><span class='va'>lansing</span><span class='op'>)</span><span class='op'>$</span><span class='va'>maple</span><span class='op'>)</span>
    <span class='fu'>o.ring</span><span class='op'>(</span><span class='va'>x</span><span class='op'>)</span>
</div><div class='img'><img src='o.ring-1.png' alt='' width='700' height='433' /></div><div class='input'>
</div></pre>
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