add geoid conversion script to github pages

Author: bakkerbakker

_layouts/default.html

@@ -28,6 +28,10 @@ <h1><a href="{{ "/" | absolute_url }}">{{ site.title | default: site.github.repo
         <a href="https://polargeospatialcenter.github.io/pgc-code-tutorials/dynamic_stac_api/desktop_gis_stac_access.html">ArcGIS Pro and QGIS Desktop Tutorials </a>
         </p>
 
+        <p><b>DEM Vertical Reference Transformation</b><br />
+        <a href="https://polargeospatialcenter.github.io/pgc-code-tutorials/geoid_conversion/geoid_conversion.html">Ellipsoid to Orthometric (Geoid) Conversion Tutorial </a><br />
+        </p>
+
         {% if site.github.is_project_page %}
         <p class="view"><a href="{{ site.github.repository_url }}">View the Project on GitHub <small>{{ site.github.repository_nwo }}</small></a></p>
         {% endif %}