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fa-github"> Edit on GitHub</a> + </li> + </ul><div class="rst-breadcrumbs-buttons" role="navigation" aria-label="Sequential page navigation"> + <a href="topocentric.html" class="btn btn-neutral float-left" title="Geocentric to topocentric conversion" accesskey="p"><span class="fa fa-arrow-circle-left" aria-hidden="true"></span> Previous</a> + <a href="../transformations/index.html" class="btn btn-neutral float-right" title="Transformations" accesskey="n">Next <span class="fa fa-arrow-circle-right" aria-hidden="true"></span></a> + </div> + <hr/> +</div> + <div role="main" class="document" itemscope="itemscope" itemtype="http://schema.org/Article"> + <div itemprop="articleBody"> + + <section id="unit-conversion"> +<span id="unitconvert"></span><h1>Unit conversion<a class="headerlink" href="#unit-conversion" title="Permalink to this headline">¶</a></h1> +<div class="versionadded"> +<p><span class="versionmodified added">New in version 5.0.0.</span></p> +</div> +<p>Convert between various distance, angular and time units.</p> +<table class="docutils align-default"> +<colgroup> +<col style="width: 27%" /> +<col style="width: 73%" /> +</colgroup> +<tbody> +<tr class="row-odd"><td><p><strong>Alias</strong></p></td> +<td><p>unitconvert</p></td> +</tr> +<tr class="row-even"><td><p><strong>Domain</strong></p></td> +<td><p>2D, 3D or 4D</p></td> +</tr> +<tr class="row-odd"><td><p><strong>Input type</strong></p></td> +<td><p>Any</p></td> +</tr> +<tr class="row-even"><td><p><strong>Output type</strong></p></td> +<td><p>Any</p></td> +</tr> +</tbody> +</table> +<p>There are many examples of coordinate reference systems that are expressed in +other units than the meter. There are also many cases where temporal data +has to be translated to different units. The <cite>unitconvert</cite> operation takes care +of that.</p> +<p>Many North American systems are defined with coordinates in feet. For example +in Vermont:</p> +<div class="highlight-none notranslate"><div class="highlight"><pre><span></span>+proj=pipeline ++step +proj=tmerc +lat_0=42.5 +lon_0=-72.5 +k_0=0.999964286 +x_0=500000.00001016 +y_0=0 ++step +proj=unitconvert +xy_in=m +xy_out=us-ft +</pre></div> +</div> +<p>Often when working with GNSS data the timestamps are presented in GPS-weeks, +but when the data transformed with the <cite>helmert</cite> operation timestamps are +expected to be in units of decimalyears. This can be fixed with <cite>unitconvert</cite>:</p> +<div class="highlight-none notranslate"><div class="highlight"><pre><span></span>+proj=pipeline ++step +proj=unitconvert +t_in=gps_week +t_out=decimalyear ++step +proj=helmert +epoch=2000.0 +t_obs=2017.5 ... +</pre></div> +</div> +<section id="parameters"> +<h2>Parameters<a class="headerlink" href="#parameters" title="Permalink to this headline">¶</a></h2> +<dl class="std option"> +<dt class="sig sig-object std" id="cmdoption-arg-xy_in"> +<span id="cmdoption-arg-xy-in"></span><span class="sig-name descname"><span class="pre">+xy_in</span></span><span class="sig-prename descclassname"><span class="pre">=<unit></span> <span class="pre">or</span> <span class="pre"><conversion_factor></span></span><a class="headerlink" href="#cmdoption-arg-xy_in" title="Permalink to this definition">¶</a></dt> +<dd><p>Horizontal input units. See <a class="reference internal" href="#distance-units"><span class="std std-ref">Distance units</span></a> and <a class="reference internal" href="#angular-units"><span class="std std-ref">Angular units</span></a> +for a list of available units. <cite><conversion_factor></cite> is the conversion factor +from the input unit to metre for linear units, or to radian for angular +units.</p> +</dd></dl> + +<dl class="std option"> +<dt class="sig sig-object std" id="cmdoption-arg-xy_out"> +<span id="cmdoption-arg-xy-out"></span><span class="sig-name descname"><span class="pre">+xy_out</span></span><span class="sig-prename descclassname"><span class="pre">=<unit></span> <span class="pre">or</span> <span class="pre"><conversion_factor></span></span><a class="headerlink" href="#cmdoption-arg-xy_out" title="Permalink to this definition">¶</a></dt> +<dd><p>Horizontal output units. See <a class="reference internal" href="#distance-units"><span class="std std-ref">Distance units</span></a> and <a class="reference internal" href="#angular-units"><span class="std std-ref">Angular units</span></a> +for a list of available units. <cite><conversion_factor></cite> is the conversion factor +from the output unit to metre for linear units, or to radian for angular +units.</p> +</dd></dl> + +<dl class="std option"> +<dt class="sig sig-object std" id="cmdoption-arg-z_in"> +<span id="cmdoption-arg-z-in"></span><span class="sig-name descname"><span class="pre">+z_in</span></span><span class="sig-prename descclassname"><span class="pre">=<unit></span> <span class="pre">or</span> <span class="pre"><conversion_factor></span></span><a class="headerlink" href="#cmdoption-arg-z_in" title="Permalink to this definition">¶</a></dt> +<dd><p>Vertical output units. See <a class="reference internal" href="#distance-units"><span class="std std-ref">Distance units</span></a> and <a class="reference internal" href="#angular-units"><span class="std std-ref">Angular units</span></a> +for a list of available units. <cite><conversion_factor></cite> is the conversion factor +from the input unit to metre for linear units, or to radian for angular +units.</p> +</dd></dl> + +<dl class="std option"> +<dt class="sig sig-object std" id="cmdoption-arg-z_out"> +<span id="cmdoption-arg-z-out"></span><span class="sig-name descname"><span class="pre">+z_out</span></span><span class="sig-prename descclassname"><span class="pre">=<unit></span> <span class="pre">or</span> <span class="pre"><conversion_factor></span></span><a class="headerlink" href="#cmdoption-arg-z_out" title="Permalink to this definition">¶</a></dt> +<dd><p>Vertical output units. See <a class="reference internal" href="#distance-units"><span class="std std-ref">Distance units</span></a> and <a class="reference internal" href="#angular-units"><span class="std std-ref">Angular units</span></a> +for a list of available units. <cite><conversion_factor></cite> is the conversion factor +from the output unit to metre for linear units, or to radian for angular +units.</p> +</dd></dl> + +<dl class="std option"> +<dt class="sig sig-object std" id="cmdoption-arg-t_in"> +<span id="cmdoption-arg-t-in"></span><span class="sig-name descname"><span class="pre">+t_in</span></span><span class="sig-prename descclassname"><span class="pre">=<unit></span></span><a class="headerlink" href="#cmdoption-arg-t_in" title="Permalink to this definition">¶</a></dt> +<dd><p>Temporal input units. See <a class="reference internal" href="#time-units"><span class="std std-ref">Time units</span></a> for a list of available units.</p> +</dd></dl> + +<dl class="std option"> +<dt class="sig sig-object std" id="cmdoption-arg-t_out"> +<span id="cmdoption-arg-t-out"></span><span class="sig-name descname"><span class="pre">+t_out</span></span><span class="sig-prename descclassname"><span class="pre">=<unit></span></span><a class="headerlink" href="#cmdoption-arg-t_out" title="Permalink to this definition">¶</a></dt> +<dd><p>Temporal output units. See <a class="reference internal" href="#time-units"><span class="std std-ref">Time units</span></a> for a list of available units.</p> +</dd></dl> + +</section> +<section id="distance-units"> +<span id="id1"></span><h2>Distance units<a class="headerlink" href="#distance-units" title="Permalink to this headline">¶</a></h2> +<p>In the table below all distance units supported by PROJ are listed. +The same list can also be produced on the command line with <strong class="program">proj</strong> or +<strong class="program">cs2cs</strong>, by adding the <cite>-lu</cite> flag when calling the utility.</p> +<table class="docutils align-default"> +<colgroup> +<col style="width: 23%" /> +<col style="width: 77%" /> +</colgroup> +<thead> +<tr class="row-odd"><th class="head"><p>Label</p></th> +<th class="head"><p>Name</p></th> +</tr> +</thead> +<tbody> +<tr class="row-even"><td><p>km</p></td> +<td><p>Kilometer</p></td> +</tr> +<tr class="row-odd"><td><p>m</p></td> +<td><p>Meter</p></td> +</tr> +<tr class="row-even"><td><p>dm</p></td> +<td><p>Decimeter</p></td> +</tr> +<tr class="row-odd"><td><p>cm</p></td> +<td><p>Centimeter</p></td> +</tr> +<tr class="row-even"><td><p>mm</p></td> +<td><p>Millimeter</p></td> +</tr> +<tr class="row-odd"><td><p>kmi</p></td> +<td><p>International Nautical Mile</p></td> +</tr> +<tr class="row-even"><td><p>in</p></td> +<td><p>International Inch</p></td> +</tr> +<tr class="row-odd"><td><p>ft</p></td> +<td><p>International Foot</p></td> +</tr> +<tr class="row-even"><td><p>yd</p></td> +<td><p>International Yard</p></td> +</tr> +<tr class="row-odd"><td><p>mi</p></td> +<td><p>International Statute Mile</p></td> +</tr> +<tr class="row-even"><td><p>fath</p></td> +<td><p>International Fathom</p></td> +</tr> +<tr class="row-odd"><td><p>ch</p></td> +<td><p>International Chain</p></td> +</tr> +<tr class="row-even"><td><p>link</p></td> +<td><p>International Link</p></td> +</tr> +<tr class="row-odd"><td><p>us-in</p></td> +<td><p>U.S. Surveyor’s Inch</p></td> +</tr> +<tr class="row-even"><td><p>us-ft</p></td> +<td><p>U.S. Surveyor’s Foot</p></td> +</tr> +<tr class="row-odd"><td><p>us-yd</p></td> +<td><p>U.S. Surveyor’s Yard</p></td> +</tr> +<tr class="row-even"><td><p>us-ch</p></td> +<td><p>U.S. Surveyor’s Chain</p></td> +</tr> +<tr class="row-odd"><td><p>us-mi</p></td> +<td><p>U.S. Surveyor’s Statute Mile</p></td> +</tr> +<tr class="row-even"><td><p>ind-yd</p></td> +<td><p>Indian Yard</p></td> +</tr> +<tr class="row-odd"><td><p>ind-ft</p></td> +<td><p>Indian Foot</p></td> +</tr> +<tr class="row-even"><td><p>ind-ch</p></td> +<td><p>Indian Chain</p></td> +</tr> +</tbody> +</table> +</section> +<section id="angular-units"> +<span id="id2"></span><h2>Angular units<a class="headerlink" href="#angular-units" title="Permalink to this headline">¶</a></h2> +<div class="versionadded"> +<p><span class="versionmodified added">New in version 5.2.0.</span></p> +</div> +<p>In the table below all angular units supported by PROJ <cite>unitconvert</cite> are listed.</p> +<table class="docutils align-default"> +<colgroup> +<col style="width: 23%" /> +<col style="width: 77%" /> +</colgroup> +<thead> +<tr class="row-odd"><th class="head"><p>Label</p></th> +<th class="head"><p>Name</p></th> +</tr> +</thead> +<tbody> +<tr class="row-even"><td><p>deg</p></td> +<td><p>Degree</p></td> +</tr> +<tr class="row-odd"><td><p>grad</p></td> +<td><p>Grad</p></td> +</tr> +<tr class="row-even"><td><p>rad</p></td> +<td><p>Radian</p></td> +</tr> +</tbody> +</table> +</section> +<section id="time-units"> +<span id="id3"></span><h2>Time units<a class="headerlink" href="#time-units" title="Permalink to this headline">¶</a></h2> +<p>In the table below all time units supported by PROJ are listed.</p> +<blockquote> +<div><div class="admonition note"> +<p class="admonition-title">Note</p> +<p>When converting time units from a date-only format (<cite>yyyymmdd</cite>), PROJ +assumes a time value of 00:00 midnight. When converting time units +to a date-only format, PROJ rounds to the <em>nearest</em> date at 00:00 +midnight. That is, any time values less than 12:00 noon will round to +00:00 on the same day. Time values greater than or equal to 12:00 noon +will round to 00:00 on the following day.</p> +</div> +</div></blockquote> +<table class="docutils align-default"> +<colgroup> +<col style="width: 33%" /> +<col style="width: 67%" /> +</colgroup> +<thead> +<tr class="row-odd"><th class="head"><p>Label</p></th> +<th class="head"><p>Name</p></th> +</tr> +</thead> +<tbody> +<tr class="row-even"><td><p>mjd</p></td> +<td><p>Modified Julian date</p></td> +</tr> +<tr class="row-odd"><td><p>decimalyear</p></td> +<td><p>Decimal year</p></td> +</tr> +<tr class="row-even"><td><p>gps_week</p></td> +<td><p>GPS Week</p></td> +</tr> +<tr class="row-odd"><td><p>yyyymmdd</p></td> +<td><p>Date in yyyymmdd format</p></td> +</tr> +</tbody> +</table> +</section> +</section> + + + </div> + </div> + <footer><div class="rst-footer-buttons" role="navigation" aria-label="Footer"> + <a href="topocentric.html" class="btn btn-neutral float-left" title="Geocentric to topocentric conversion" accesskey="p" rel="prev"><span class="fa fa-arrow-circle-left" aria-hidden="true"></span> Previous</a> + <a href="../transformations/index.html" class="btn btn-neutral float-right" title="Transformations" accesskey="n" rel="next">Next <span class="fa fa-arrow-circle-right" aria-hidden="true"></span></a> + </div> + + <hr/> + + <div role="contentinfo"> + <p>© Copyright 1983-2022. + <span class="lastupdated">Last updated on 22 Mar 2022. + </span></p> + </div> + + Built with <a href="https://www.sphinx-doc.org/">Sphinx</a> using a + <a href="https://github.com/readthedocs/sphinx_rtd_theme">theme</a> + provided by <a href="https://readthedocs.org">Read the Docs</a>. + + +</footer> + </div> + </div> + </section> + </div> + <script> + jQuery(function () { + SphinxRtdTheme.Navigation.enable(true); + }); + </script> + +</body> +</html>
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