or" aria-label="anchor" href="#arg-crs"></a></dt>
<dd><p>EPSG code of a coordinate reference system to use for spatial
operations. No CRS is assumed by default (<code>NULL</code>), implying an
abstract landscape not tied to any real-world geographic region (when
<code>landscape = "blank"</code> or when <code>landscape</code> is a custom-defined
geographic landscape), or implying WGS-84 (EPSG 4326) coordinate system
when a real Earth landscape was defined (<code>landscape =
  "naturalearth"</code>).</p></dd>