modules/custom/iso/templates/iso--node--research-site.tpl.php
<gmd:description>
<?php print render($content['field_description']); ?>
</gmd:description>
<gmd:geographicElement>
<gmd:EX_GeographicBoundingBox>
<?php print render($content['field_coordinates']); ?>
</gmd:EX_GeographicBoundingBox>
</gmd:geographicElement>