fixed handling for non-existant spatial coverage resource schema.org representation
{% if temporal_coverage %}
"temporalCoverage": "{{ temporal_coverage.start_date }}/{{ temporal_coverage.end_date }}",
{% endif %}
- {% if spatial_coverage %}
+ {% if spatial_coverage.exists %}
"spatialCoverage": {
"@type": "Place",
{% if spatial_coverage.name %}
