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to indicate a coordinate system set up so that one axis is parallel
to a coastline."><meta property="og:description" content="Draws arrows on a map to indicate a coordinate system, e.g. for an
to indicate a coordinate system set up so that one axis is parallel
to a coastline."></head><body>
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      <h1>Draw a Coordinate System</h1>
      <small class="dont-index">Source: <a href="https://github.com/dankelley/oce/blob/HEAD/R/map.R" class="external-link"><code>R/map.R</code></a></small>
      <div class="d-none name"><code>mapCoordinateSystem.Rd</code></div>
    </div>

    <div class="ref-description section level2">
    <p>Draws arrows on a map to indicate a coordinate system, e.g. for an
to indicate a coordinate system set up so that one axis is parallel
to a coastline.</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="fu">mapCoordinateSystem</span><span class="op">(</span><span class="va">longitude</span>, <span class="va">latitude</span>, L <span class="op">=</span> <span class="fl">100</span>, phi <span class="op">=</span> <span class="fl">0</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-longitude">longitude<a class="anchor" aria-label="anchor" href="#arg-longitude"></a></dt>
<dd><p>numeric vector of longitudes in degrees.</p></dd>


<dt id="arg-latitude">latitude<a class="anchor" aria-label="anchor" href="#arg-latitude"></a></dt>
<dd><p>numeric vector of latitudes in degrees.</p></dd>


<dt id="arg-l">L<a class="anchor" aria-label="anchor" href="#arg-l"></a></dt>
<dd><p>axis length in km.</p></dd>


<dt id="arg-phi">phi<a class="anchor" aria-label="anchor" href="#arg-phi"></a></dt>
<dd><p>angle, in degrees counterclockwise, that the "x" axis
makes to a line of latitude.</p></dd>


<dt id="arg--">...<a class="anchor" aria-label="anchor" href="#arg--"></a></dt>
<dd><p>plotting arguments, passed to <code><a href="mapArrows.html">mapArrows()</a></code>;
see “Examples” for how to control the arrow-head size.</p></dd>

</dl></div>
    <div class="section level2">
    <h2 id="details">Details<a class="anchor" aria-label="anchor" href="#details"></a></h2>
    <p>This is a preliminary version of this function. It only
works if the lines of constant latitude are horizontal on the plot.</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>
library(oce)
if (requireNamespace("ocedata", quietly=TRUE)) {
    data(coastlineWorldFine, package="ocedata")
    HfxLon &lt;- -63.5752
    HfxLat &lt;- 44.6488
    mapPlot(coastlineWorldFine, proj="+proj=merc",
        longitudelim=HfxLon+c(-2,2), latitudelim=HfxLat+c(-2,2),
        col=lightgrey")
    mapCoordinateSystem(HfxLon, HfxLat, phi=45, length=0.05)
   }
</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 functions related to maps:
<code><a href="formatPosition.html">formatPosition</a>()</code>,
<code><a href="lonlat2map.html">lonlat2map</a>()</code>,
<code><a href="lonlat2utm.html">lonlat2utm</a>()</code>,
<code><a href="map2lonlat.html">map2lonlat</a>()</code>,
<code><a href="mapArrows.html">mapArrows</a>()</code>,
<code><a href="mapAxis.html">mapAxis</a>()</code>,
<code><a href="mapContour.html">mapContour</a>()</code>,
<code><a href="mapDirectionField.html">mapDirectionField</a>()</code>,
<code><a href="mapGrid.html">mapGrid</a>()</code>,
<code><a href="mapImage.html">mapImage</a>()</code>,
<code><a href="mapLines.html">mapLines</a>()</code>,
<code><a href="mapLocator.html">mapLocator</a>()</code>,
<code><a href="mapLongitudeLatitudeXY.html">mapLongitudeLatitudeXY</a>()</code>,
<code><a href="mapPlot.html">mapPlot</a>()</code>,
<code><a href="mapPoints.html">mapPoints</a>()</code>,
<code><a href="mapPolygon.html">mapPolygon</a>()</code>,
<code><a href="mapScalebar.html">mapScalebar</a>()</code>,
<code><a href="mapText.html">mapText</a>()</code>,
<code><a href="mapTissot.html">mapTissot</a>()</code>,
<code><a href="oceCRS.html">oceCRS</a>()</code>,
<code><a href="oceProject.html">oceProject</a>()</code>,
<code><a href="shiftLongitude.html">shiftLongitude</a>()</code>,
<code><a href="usrLonLat.html">usrLonLat</a>()</code>,
<code><a href="utm2lonlat.html">utm2lonlat</a>()</code></p></div>
    </div>
    <div class="section level2">
    <h2 id="author">Author<a class="anchor" aria-label="anchor" href="#author"></a></h2>
    <p>Chantelle Layton</p>
    </div>

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