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    <p>Thank you Even!</p>
    <p>To R users, would this be appropriate advice regarding PROJ
      strings? - please comment or edit where needed:</p>
    <ol>
      <li>Using a PROJ string to specify a CRS is <a
          moz-do-not-send="true"
href="https://proj.org/development/reference/functions.html#c.proj_create">discouraged</a>
        and currently not much documented by PROJ (PROJ strings are used
        for coordinate operations instead). At least for registered
        CRSs, always use AUTHORITY:CODE or <a moz-do-not-send="true"
          href="https://docs.opengeospatial.org/is/18-010r7/18-010r7.html">WKT2</a>,
        not PROJ strings.</li>
      <li>Also custom CRSs are ideally specified as <a
          href="https://docs.opengeospatial.org/is/18-010r7/18-010r7.html">WKT2</a>,
        or more conveniently as (currently not yet official) <a
          href="https://proj.org/specifications/projjson.html">PROJJSON</a>,
        which follows the WKT2 structure.</li>
      <li>When specifying a custom CRS with a PROJ string, the WGS84
        ensemble datum (<a moz-do-not-send="true"
href="https://epsg.org/datum_6326/World-Geodetic-System-1984-ensemble.html">EPSG:6326</a>)
        will automatically be adopted if no '+ellps' is specified (and
        with '+ellps', the datum is considered as 'unknown'). Note that
        EPSG:6326 always refers to the latest WGS84 realization, not to
        a fixed one. If these conditions are fine for your usecase, then
        there's no problem.</li>
      <li>For backward compatibility reasons, PROJ strings with
        '+towgs84' or '+datum', although deprecated, will remain
        supported by PROJ and GDAL.<br>
      </li>
      <li>When specifying a custom CRS that doesn't use the WGS84, NAD27
        or NAD83 datum (which can be specified with '+datum'), it is
        better to use <a moz-do-not-send="true"
          href="https://docs.opengeospatial.org/is/18-010r7/18-010r7.html">WKT2</a>
        or <a moz-do-not-send="true"
          href="https://proj.org/specifications/projjson.html">PROJJSON</a>
        and properly refer the geodetic datum. A typically less accurate
        alternative is defining as a BOUNDCRS by specifying '+towgs84'
        transformation parameters.</li>
    </ol>
    <p>With regards</p>
    <p>Floris<br>
    </p>
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