Infer geometry type if subjects include a geometry type

Closes #35

lib/geo_combine/geoblacklight.rb

@@ -42,6 +42,7 @@ def enhance_metadata
       metadata.each do |key, value|
         translate_formats(key, value)
         enhance_subjects(key, value)
+        infer_geometry_type_from_subject(key, value)
         format_proper_date(key, value)
         fields_should_be_array(key, value)
         translate_geometry_type(key, value)
@@ -106,6 +107,17 @@ def translate_geometry_type(key, value)
       metadata[key] = geometry_types[value]
     end
 
+    ##
+    # Enhances empty 'layer_geom_type_s' field by populating from related subject
+    def infer_geometry_type_from_subject(key, value)
+      return unless key == 'layer_geom_type_s' && value.blank?
+
+      # If any subjects match a known geometry type, use the first that does as the geometry type
+      metadata['dc_subject_sm'].find { |subject| geometry_types.value?(subject.capitalize) }&.tap do |subject|
+        metadata[key] = subject.capitalize
+      end
+    end
+
     ##
     # Enhances the 'dc_subject_sm' field by translating subjects to ISO topic
     # categories

spec/lib/geo_combine/geoblacklight_spec.rb

@@ -60,6 +60,12 @@
     it 'formats the geometry type field' do
       expect(enhanced_geobl.metadata['layer_geom_type_s']).to eq 'Polygon'
     end
+
+    it 'populates the geometry type field from the subject field if not set' do
+      enhanced_from_subject_geobl = described_class.new(basic_geoblacklight, 'dc_subject_sm' => ['polygon'])
+      enhanced_from_subject_geobl.enhance_metadata
+      expect(enhanced_from_subject_geobl.metadata['layer_geom_type_s']).to eq 'Polygon'
+    end
   end
 
   describe '#valid?' do