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tidal model object that was created by as.tidem() or tidem()."><meta property="og:description" content="This creates a time-series of predicted tides, based on a
tidal model object that was created by as.tidem() or tidem()."></head><body>
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      <h1>Predict a Tidal Signal</h1>
      <small class="dont-index">Source: <a href="https://github.com/dankelley/oce/blob/HEAD/R/tides.R" class="external-link"><code>R/tides.R</code></a></small>
      <div class="d-none name"><code>predict.tidem.Rd</code></div>
    </div>

    <div class="ref-description section level2">
    <p>This creates a time-series of predicted tides, based on a
tidal model object that was created by <code><a href="as.tidem.html">as.tidem()</a></code> or <code><a href="tidem.html">tidem()</a></code>.</p>
    </div>

    <div class="section level2">
    <h2 id="ref-usage">Usage<a class="anchor" aria-label="anchor" href="#ref-usage"></a></h2>
    <div class="sourceCode"><pre class="sourceCode r"><code><span><span class="co"># S3 method for class 'tidem'</span></span>
<span><span class="fu"><a href="https://rdrr.io/r/stats/predict.html" class="external-link">predict</a></span><span class="op">(</span><span class="va">object</span>, <span class="va">newdata</span>, <span class="va">...</span><span class="op">)</span></span></code></pre></div>
    </div>

    <div class="section level2">
    <h2 id="arguments">Arguments<a class="anchor" aria-label="anchor" href="#arguments"></a></h2>


<dl><dt id="arg-object">object<a class="anchor" aria-label="anchor" href="#arg-object"></a></dt>
<dd><p>a <a href="tidem-class.html">tidem</a> object.</p></dd>


<dt id="arg-newdata">newdata<a class="anchor" aria-label="anchor" href="#arg-newdata"></a></dt>
<dd><p>vector of POSIXt times at which to make the
prediction.  For models created with <code><a href="tidem.html">tidem()</a></code>,
the <code>newdata</code> argument is optional, and if it is not provided, then
the predictions are at the observation times given to
<code><a href="tidem.html">tidem()</a></code>. However, <code>newdata</code> is required  if <code><a href="as.tidem.html">as.tidem()</a></code>
had been used to create <code>object</code>.</p></dd>


<dt id="arg--">...<a class="anchor" aria-label="anchor" href="#arg--"></a></dt>
<dd><p>optional arguments passed on to children.</p></dd>

</dl></div>
    <div class="section level2">
    <h2 id="value">Value<a class="anchor" aria-label="anchor" href="#value"></a></h2>
    <p>A vector of predictions.</p>
    </div>
    <div class="section level2">
    <h2 id="details">Details<a class="anchor" aria-label="anchor" href="#details"></a></h2>
    <p>All the tidal constituents that are stored in <code>object</code> are used,
not just those that are statistically significant or that have amplitude
exceeding any particular value.  In this respect, <code>predict.tidem()</code>
follows a pattern established by e.g. <code><a href="https://rdrr.io/r/stats/predict.lm.html" class="external-link">predict.lm()</a></code>.  Note that
the constituents in <code>object</code> are straightforward if it
was constructed with <code><a href="as.tidem.html">as.tidem()</a></code>, but considerably more complicated
for <code><a href="tidem.html">tidem()</a></code>, and so the documentation for the latter ought to
be studied closely, especially with regard to the Rayleigh criterion.</p>
    </div>
    <div class="section level2">
    <h2 id="sample-of-usage">Sample of Usage<a class="anchor" aria-label="anchor" href="#sample-of-usage"></a></h2>


<div class="sourceCode"><pre><code><span></span>
<span><span class="co"># prediction at specified times</span></span>
<span><span class="fu"><a href="https://rdrr.io/r/utils/data.html" class="external-link">data</a></span><span class="op">(</span><span class="va">sealevel</span><span class="op">)</span></span>
<span><span class="va">m</span> <span class="op">&lt;-</span> <span class="fu"><a href="../reference/tidem.html">tidem</a></span><span class="op">(</span><span class="va">sealevel</span><span class="op">)</span></span>
<span><span class="co"># Check fit over 2 days (interpolating to finer timescale)</span></span>
<span><span class="va">look</span> <span class="op">&lt;-</span> <span class="fl">1</span><span class="op">:</span><span class="fl">48</span></span>
<span><span class="va">time</span> <span class="op">&lt;-</span> <span class="va">sealevel</span><span class="op">[[</span><span class="st">"time"</span><span class="op">]</span><span class="op">]</span></span>
<span><span class="va">elevation</span> <span class="op">&lt;-</span> <span class="va">sealevel</span><span class="op">[[</span><span class="st">"elevation"</span><span class="op">]</span><span class="op">]</span></span>
<span><span class="fu"><a href="../reference/oce.plot.ts.html">oce.plot.ts</a></span><span class="op">(</span><span class="va">time</span><span class="op">[</span><span class="va">look</span><span class="op">]</span>, <span class="va">elevation</span><span class="op">[</span><span class="va">look</span><span class="op">]</span><span class="op">)</span></span>
<span><span class="co"># 360s = 10 minute timescale</span></span>
<span><span class="va">t</span> <span class="op">&lt;-</span> <span class="fu"><a href="https://rdrr.io/r/base/seq.html" class="external-link">seq</a></span><span class="op">(</span>from<span class="op">=</span><span class="va">time</span><span class="op">[</span><span class="fl">1</span><span class="op">]</span>, to<span class="op">=</span><span class="va">time</span><span class="op">[</span><span class="fu"><a href="https://rdrr.io/r/base/Extremes.html" class="external-link">max</a></span><span class="op">(</span><span class="va">look</span><span class="op">)</span><span class="op">]</span>, by<span class="op">=</span><span class="fl">360</span><span class="op">)</span></span>
<span><span class="fu"><a href="https://rdrr.io/r/graphics/lines.html" class="external-link">lines</a></span><span class="op">(</span><span class="va">t</span>, <span class="fu"><a href="https://rdrr.io/r/stats/predict.html" class="external-link">predict</a></span><span class="op">(</span><span class="va">m</span>, newdata<span class="op">=</span><span class="va">t</span><span class="op">)</span>, col<span class="op">=</span><span class="st">"red"</span><span class="op">)</span></span>
<span><span class="fu"><a href="https://rdrr.io/r/graphics/legend.html" class="external-link">legend</a></span><span class="op">(</span><span class="st">"topright"</span>, col<span class="op">=</span><span class="fu"><a href="https://rdrr.io/r/base/c.html" class="external-link">c</a></span><span class="op">(</span><span class="st">"black"</span>,<span class="st">"red"</span><span class="op">)</span>,</span>
<span>legend<span class="op">=</span><span class="fu"><a href="https://rdrr.io/r/base/c.html" class="external-link">c</a></span><span class="op">(</span><span class="st">"data"</span>,<span class="st">"model"</span><span class="op">)</span>,lwd<span class="op">=</span><span class="fl">1</span><span class="op">)</span></span></code></pre></div>

    </div>
    <div class="section level2">
    <h2 id="see-also">See also<a class="anchor" aria-label="anchor" href="#see-also"></a></h2>
    <div class="dont-index"><p>Other things related to tides:
<code><a href="sub-sub-tidem-method.html">[[,tidem-method</a></code>,
<code>[[&lt;-,tidem-method</code>,
<code><a href="as.tidem.html">as.tidem</a>()</code>,
<code><a href="plot-tidem-method.html">plot,tidem-method</a></code>,
<code><a href="summary-tidem-method.html">summary,tidem-method</a></code>,
<code><a href="tidalCurrent.html">tidalCurrent</a></code>,
<code><a href="tidedata.html">tidedata</a></code>,
<code><a href="tidem.html">tidem</a></code>,
<code><a href="tidem-class.html">tidem-class</a></code>,
<code><a href="tidemAstron.html">tidemAstron</a>()</code>,
<code><a href="tidemVuf.html">tidemVuf</a>()</code>,
<code><a href="webtide.html">webtide</a>()</code></p></div>
    </div>
    <div class="section level2">
    <h2 id="author">Author<a class="anchor" aria-label="anchor" href="#author"></a></h2>
    <p>Dan Kelley</p>
    </div>

    <div class="section level2">
    <h2 id="ref-examples">Examples<a class="anchor" aria-label="anchor" href="#ref-examples"></a></h2>
    <div class="sourceCode"><pre class="sourceCode r"><code><span class="r-in"><span></span></span>
<span class="r-in"><span><span class="co"># Show non-tidal sealevel signal in Halifax Harbour during</span></span></span>
<span class="r-in"><span><span class="co"># the year 2002. The spike resulted from Hurricane Juan.</span></span></span>
<span class="r-in"><span><span class="kw"><a href="https://rdrr.io/r/base/library.html" class="external-link">library</a></span><span class="op">(</span><span class="va"><a href="https://dankelley.github.io/oce/">oce</a></span><span class="op">)</span></span></span>
<span class="r-in"><span><span class="fu"><a href="https://rdrr.io/r/utils/data.html" class="external-link">data</a></span><span class="op">(</span><span class="va">sealevel</span><span class="op">)</span></span></span>
<span class="r-in"><span><span class="va">time</span> <span class="op">&lt;-</span> <span class="va">sealevel</span><span class="op">[[</span><span class="st">"time"</span><span class="op">]</span><span class="op">]</span></span></span>
<span class="r-in"><span><span class="va">elevation</span> <span class="op">&lt;-</span> <span class="va">sealevel</span><span class="op">[[</span><span class="st">"elevation"</span><span class="op">]</span><span class="op">]</span></span></span>
<span class="r-in"><span><span class="va">prediction</span> <span class="op">&lt;-</span> <span class="fu"><a href="tidem.html">tidem</a></span><span class="op">(</span><span class="va">sealevel</span><span class="op">)</span> <span class="op">|&gt;</span> <span class="fu"><a href="https://rdrr.io/r/stats/predict.html" class="external-link">predict</a></span><span class="op">(</span><span class="op">)</span></span></span>
<span class="r-msg co"><span class="r-pr">#&gt;</span> Note: the tidal record is too short to fit for constituents: SA, PI1, S1, PSI1, GAM2, H1, H2, T2, R2</span>
<span class="r-in"><span><span class="fu"><a href="oce.plot.ts.html">oce.plot.ts</a></span><span class="op">(</span><span class="va">time</span>, <span class="va">elevation</span> <span class="op">-</span> <span class="va">prediction</span><span class="op">)</span></span></span>
<span class="r-plt img"><img src="predict.tidem-1.png" alt="" width="700" height="700"></span>
<span class="r-in"><span></span></span>
</code></pre></div>
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