diff --git a/pygeometa/core.py b/pygeometa/core.py
index 1c7a7df..503c7e6 100644
--- a/pygeometa/core.py
+++ b/pygeometa/core.py
@@ -45,8 +45,8 @@
 # =================================================================
 
 from collections.abc import Mapping
-from datetime import date, datetime
 from importlib.metadata import version, PackageNotFoundError
+import datetime
 import json
 import logging
 import os
@@ -125,14 +125,14 @@ def normalize_datestring(datestring: str, format_: str = 'default') -> str:
     :returns: string of properly formatted datestring
     """
 
-    today_and_now = datetime.utcnow()
+    today_and_now = datetime.datetime.now(datetime.UTC)
 
     re1 = r'\$Date: (?P<year>\d{4})'
     re2 = r'\$Date: (?P<date>\d{4}-\d{2}-\d{2}) (?P<time>\d{2}:\d{2}:\d{2})'
     re3 = r'(?P<start>.*)\$Date: (?P<year>\d{4}).*\$(?P<end>.*)'
 
     try:
-        if isinstance(datestring, date):
+        if isinstance(datestring, datetime.date):
             if datestring.year < 1900:
                 datestring2 = '{0.day:02d}.{0.month:02d}.{0.year:4d}'.format(
                     datestring)
diff --git a/pygeometa/schemas/cwl/__init__.py b/pygeometa/schemas/cwl/__init__.py
index 958eade..b7b6925 100644
--- a/pygeometa/schemas/cwl/__init__.py
+++ b/pygeometa/schemas/cwl/__init__.py
@@ -108,7 +108,7 @@ def import_(self, metadata: str) -> dict:
 
         now = datetime.datetime.now(datetime.UTC)
 
-        wf = list(filter(lambda x: x['class'] == 'Workflow', metadata['$graph']))[0]  # noqa
+        wf = list(filter(lambda x: x['class'] == 'Workflow', metadata.get('$graph')))[0]  # noqa
 
         mcf['metadata']['identifier'] = wf['id']
         mcf['metadata']['hierarchylevel'] = 'application'
diff --git a/pygeometa/schemas/iso19139/__init__.py b/pygeometa/schemas/iso19139/__init__.py
index 9e93168..8edee55 100644
--- a/pygeometa/schemas/iso19139/__init__.py
+++ b/pygeometa/schemas/iso19139/__init__.py
@@ -136,15 +136,19 @@ def import_(self, metadata: str) -> dict:
 
         mcf['identification']['extents'] = {
             'spatial': [{
-                'bbox': [
+                'bbox': []
+            }],
+            'temporal': []
+        }
+        try:
+            mcf['identification']['extents']['spatial'][0]['bbox'] = [
                     ast.literal_eval(identification.extent.boundingBox.minx),
                     ast.literal_eval(identification.extent.boundingBox.miny),
                     ast.literal_eval(identification.extent.boundingBox.maxx),
                     ast.literal_eval(identification.extent.boundingBox.maxy)
                 ]
-            }],
-            'temporal': []
-        }
+        except ValueError as err:
+            LOGGER.info(f'boundingBox missing: {err}')
 
         temp_extent = {
             'begin': None,
diff --git a/tests/iso19139-no-bbox.xml b/tests/iso19139-no-bbox.xml
new file mode 100644
index 0000000..636183b
--- /dev/null
+++ b/tests/iso19139-no-bbox.xml
@@ -0,0 +1,436 @@
+<gmd:MD_Metadata xmlns:gmx="http://www.isotc211.org/2005/gmx"
+    xmlns:gmd="http://www.isotc211.org/2005/gmd"
+    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xmlns:csw="http://www.opengis.net/cat/csw/2.0.2" xmlns:dc="http://purl.org/dc/elements/1.1/"
+    xmlns:dct="http://purl.org/dc/terms/" xmlns:gml="http://www.opengis.net/gml"
+    xmlns:gml32="http://www.opengis.net/gml/3.2" xmlns:ows="http://www.opengis.net/ows"
+    xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xs="http://www.w3.org/2001/XMLSchema"
+    xmlns:gco="http://www.isotc211.org/2005/gco"
+    xsi:schemaLocation="http://www.isotc211.org/2005/gmd http://www.isotc211.org/2005/gmd/gmd.xsd
+                        http://www.isotc211.org/2005/gmx http://www.isotc211.org/2005/gmx/gmx.xsd">
+    <gmd:fileIdentifier>
+        <gco:CharacterString>Database-on-the-monitoring-of-mineral-nitrogen-in-soils-of-the-SISMAP</gco:CharacterString>
+    </gmd:fileIdentifier>
+    <gmd:language>
+        <gmd:LanguageCode codeList="http://www.loc.gov/standards/iso639-2/" codeSpace="ISO 639-2"
+            codeListValue="eng">eng</gmd:LanguageCode>
+    </gmd:language>
+    <gmd:characterSet>
+        <gmd:MD_CharacterSetCode
+            codeList="http://www.isotc211.org/2005/resources/Codelist/gmxCodelists.xml#MD_CharacterSetCode"
+            codeSpace="ISOTC211/19115" codeListValue="utf8">utf8</gmd:MD_CharacterSetCode>
+    </gmd:characterSet>
+    <gmd:hierarchyLevel>
+        <gmd:MD_ScopeCode
+            codeList="http://www.isotc211.org/2005/resources/Codelist/gmxCodelists.xml#MD_ScopeCode"
+            codeSpace="ISOTC211/19115" codeListValue="dataset">dataset</gmd:MD_ScopeCode>
+    </gmd:hierarchyLevel>
+    <gmd:contact>
+        <gmd:CI_ResponsibleParty>
+            <gmd:individualName>
+                <gco:CharacterString />
+            </gmd:individualName>
+            <gmd:organisationName>
+                <gco:CharacterString>State plant protection service</gco:CharacterString>
+            </gmd:organisationName>
+            <gmd:positionName>
+                <gco:CharacterString />
+            </gmd:positionName>
+            <gmd:contactInfo>
+                <gmd:CI_Contact>
+                    <gmd:address>
+                        <gmd:CI_Address>
+                            <gmd:postalCode>
+                                <gco:CharacterString />
+                            </gmd:postalCode>
+                            <gmd:country>
+                                <gco:CharacterString>Latvia</gco:CharacterString>
+                            </gmd:country>
+                        </gmd:CI_Address>
+                    </gmd:address>
+                    <gmd:onlineResource>
+                        <gmd:CI_OnlineResource>
+                            <gmd:linkage>
+                                <gmd:URL />
+                            </gmd:linkage>
+                        </gmd:CI_OnlineResource>
+                    </gmd:onlineResource>
+                </gmd:CI_Contact>
+            </gmd:contactInfo>
+            <gmd:role>
+                <gmd:CI_RoleCode
+                    codeList="http://www.isotc211.org/2005/resources/Codelist/gmxCodelists.xml#CI_RoleCode"
+                    codeSpace="ISOTC211/19115" codeListValue="pointOfContact">pointOfContact</gmd:CI_RoleCode>
+            </gmd:role>
+        </gmd:CI_ResponsibleParty>
+    </gmd:contact>
+    <gmd:dateStamp>
+        <gco:Date>2022-01-01</gco:Date>
+    </gmd:dateStamp>
+    <gmd:metadataStandardName>
+        <gco:CharacterString>ISO 19115:2003 - Geographic information - Metadata</gco:CharacterString>
+    </gmd:metadataStandardName>
+    <gmd:metadataStandardVersion>
+        <gco:CharacterString>ISO 19115:2003</gco:CharacterString>
+    </gmd:metadataStandardVersion>
+    <gmd:dataSetURI>
+        <gco:CharacterString>
+            http://www.vaad.gov.lv/sakums/informacija-sabiedribai/par-augsnu-agrokimisko-izpeti-un-minerala-slapekla-monitoringu.aspx</gco:CharacterString>
+    </gmd:dataSetURI>
+    <gmd:spatialRepresentationInfo>
+    </gmd:spatialRepresentationInfo>
+    <gmd:referenceSystemInfo>
+        <gmd:MD_ReferenceSystem>
+            <gmd:referenceSystemIdentifier>
+                <gmd:RS_Identifier>
+                    <gmd:code>
+                        <gco:CharacterString>urn:ogc:def:crs:EPSG:4326</gco:CharacterString>
+                    </gmd:code>
+                </gmd:RS_Identifier>
+            </gmd:referenceSystemIdentifier>
+        </gmd:MD_ReferenceSystem>
+    </gmd:referenceSystemInfo>
+    <gmd:identificationInfo>
+        <gmd:MD_DataIdentification>
+            <gmd:citation>
+                <gmd:CI_Citation>
+                    <gmd:title>
+                        <gco:CharacterString>Database on the monitoring of mineral nitrogen in soils
+                            of the SISMAP</gco:CharacterString>
+                    </gmd:title>
+                    <gmd:date>
+                        <gmd:CI_Date>
+                            <gmd:date>
+                                <gco:Date>2025-09-01</gco:Date>
+                            </gmd:date>
+                            <gmd:dateType>
+                                <gmd:CI_DateTypeCode
+                                    codeList="http://www.isotc211.org/2005/resources/Codelist/gmxCodelists.xml#CI_DateTypeCode"
+                                    codeSpace="ISOTC211/19115" codeListValue="publication">publication</gmd:CI_DateTypeCode>
+                            </gmd:dateType>
+                        </gmd:CI_Date>
+                    </gmd:date>
+                    <gmd:date>
+                        <gmd:CI_Date>
+                            <gmd:date>
+                                <gco:Date>2005 - 2020</gco:Date>
+                            </gmd:date>
+                            <gmd:dateType>
+                                <gmd:CI_DateTypeCode
+                                    codeList="http://www.isotc211.org/2005/resources/Codelist/gmxCodelists.xml#CI_DateTypeCode"
+                                    codeSpace="ISOTC211/19115" codeListValue="creation">creation</gmd:CI_DateTypeCode>
+                            </gmd:dateType>
+                        </gmd:CI_Date>
+                    </gmd:date>
+                </gmd:CI_Citation>
+            </gmd:citation>
+            <gmd:abstract>
+                <gco:CharacterString>Topsoil and subsoil sampling Sampling depth intervals,0 - 30;
+                    30-60; 60-90 cm</gco:CharacterString>
+            </gmd:abstract>
+            <gmd:status>
+                <gmd:MD_ProgressCode
+                    codeList="http://www.isotc211.org/2005/resources/Codelist/gmxCodelists.xml#MD_ProgressCode"
+                    codeSpace="ISOTC211/19115" codeListValue="onGoing">onGoing</gmd:MD_ProgressCode>
+            </gmd:status>
+            <gmd:pointOfContact>
+                <gmd:CI_ResponsibleParty>
+                    <gmd:individualName>
+                        <gco:CharacterString />
+                    </gmd:individualName>
+                    <gmd:organisationName>
+                        <gco:CharacterString>State plant protection service</gco:CharacterString>
+                    </gmd:organisationName>
+                    <gmd:positionName>
+                        <gco:CharacterString />
+                    </gmd:positionName>
+                    <gmd:contactInfo>
+                        <gmd:CI_Contact>
+                            <gmd:address>
+                                <gmd:CI_Address>
+                                    <gmd:postalCode>
+                                        <gco:CharacterString />
+                                    </gmd:postalCode>
+                                    <gmd:country>
+                                        <gco:CharacterString>Latvia</gco:CharacterString>
+                                    </gmd:country>
+                                </gmd:CI_Address>
+                            </gmd:address>
+                            <gmd:onlineResource>
+                                <gmd:CI_OnlineResource>
+                                    <gmd:linkage>
+                                        <gmd:URL />
+                                    </gmd:linkage>
+                                </gmd:CI_OnlineResource>
+                            </gmd:onlineResource>
+                        </gmd:CI_Contact>
+                    </gmd:contactInfo>
+                    <gmd:role>
+                        <gmd:CI_RoleCode
+                            codeList="http://www.isotc211.org/2005/resources/Codelist/gmxCodelists.xml#CI_RoleCode"
+                            codeSpace="ISOTC211/19115" codeListValue="pointOfContact">pointOfContact</gmd:CI_RoleCode>
+                    </gmd:role>
+                </gmd:CI_ResponsibleParty>
+            </gmd:pointOfContact>
+            <gmd:resourceMaintenance>
+                <gmd:MD_MaintenanceInformation>
+                    <gmd:maintenanceAndUpdateFrequency>
+                        <gmd:MD_MaintenanceFrequencyCode
+                            codeList="http://www.isotc211.org/2005/resources/Codelist/gmxCodelists.xml#MD_MaintenanceFrequencyCode"
+                            codeSpace="ISOTC211/19115" codeListValue="regular monitoring, yearly">regular monitoring, yearly</gmd:MD_MaintenanceFrequencyCode>
+                    </gmd:maintenanceAndUpdateFrequency>
+                </gmd:MD_MaintenanceInformation>
+            </gmd:resourceMaintenance>
+            <gmd:descriptiveKeywords>
+                <gmd:MD_Keywords>
+                    <gmd:keyword>
+                        <gco:CharacterString>EJP Country survey</gco:CharacterString>
+                    </gmd:keyword>
+                    <gmd:type>
+                        <gmd:MD_KeywordTypeCode
+                            codeList="http://www.isotc211.org/2005/resources/Codelist/gmxCodelists.xml#MD_KeywordTypeCode"
+                            codeSpace="ISOTC211/19115" codeListValue="" />
+                    </gmd:type>
+                </gmd:MD_Keywords>
+            </gmd:descriptiveKeywords>
+            <gmd:descriptiveKeywords>
+                <gmd:MD_Keywords>
+                    <gmd:keyword>
+                        <gco:CharacterString>National</gco:CharacterString>
+                    </gmd:keyword>
+                    <gmd:type>
+                        <gmd:MD_KeywordTypeCode
+                            codeList="http://www.isotc211.org/2005/resources/Codelist/gmxCodelists.xml#MD_KeywordTypeCode"
+                            codeSpace="ISOTC211/19115" codeListValue="" />
+                    </gmd:type>
+                    <gmd:thesaurusName>
+                        <gmd:CI_Citation>
+                            <gmd:title>
+                                <gmx:Anchor xlink:title="Spatial scope"
+                                    xlink:href="https://inspire.ec.europa.eu/metadata-codelist/SpatialScope">Spatial scope</gmx:Anchor>
+                            </gmd:title>
+                            <gmd:date>
+                                <gmd:CI_Date>
+                                    <gmd:date gco:nilReason="missing" />
+                                    <gmd:dateType gco:nilReason="missing" />
+                                </gmd:CI_Date>
+                            </gmd:date>
+                        </gmd:CI_Citation>
+                    </gmd:thesaurusName>
+                </gmd:MD_Keywords>
+            </gmd:descriptiveKeywords>
+            <gmd:descriptiveKeywords>
+                <gmd:MD_Keywords>
+                    <gmd:keyword>
+                        <gco:CharacterString>Country Stocktake</gco:CharacterString>
+                    </gmd:keyword>
+                    <gmd:type>
+                        <gmd:MD_KeywordTypeCode
+                            codeList="http://www.isotc211.org/2005/resources/Codelist/gmxCodelists.xml#MD_KeywordTypeCode"
+                            codeSpace="ISOTC211/19115" codeListValue="" />
+                    </gmd:type>
+                    <gmd:thesaurusName>
+                        <gmd:CI_Citation>
+                            <gmd:title>
+                                <gco:CharacterString>Source</gco:CharacterString>
+                            </gmd:title>
+                            <gmd:date>
+                                <gmd:CI_Date>
+                                    <gmd:date gco:nilReason="missing" />
+                                    <gmd:dateType gco:nilReason="missing" />
+                                </gmd:CI_Date>
+                            </gmd:date>
+                        </gmd:CI_Citation>
+                    </gmd:thesaurusName>
+                </gmd:MD_Keywords>
+            </gmd:descriptiveKeywords>
+            <gmd:descriptiveKeywords>
+                <gmd:MD_Keywords>
+                    <gmd:keyword>
+                        <gco:CharacterString>Latvia</gco:CharacterString>
+                    </gmd:keyword>
+                    <gmd:type>
+                        <gmd:MD_KeywordTypeCode
+                            codeList="http://www.isotc211.org/2005/resources/Codelist/gmxCodelists.xml#MD_KeywordTypeCode"
+                            codeSpace="ISOTC211/19115" codeListValue="" />
+                    </gmd:type>
+                    <gmd:thesaurusName>
+                        <gmd:CI_Citation>
+                            <gmd:title>
+                                <gmx:Anchor xlink:title="Country"
+                                    xlink:href="http://publications.europa.eu/resource/authority/country">Country</gmx:Anchor>
+                            </gmd:title>
+                            <gmd:date>
+                                <gmd:CI_Date>
+                                    <gmd:date gco:nilReason="missing" />
+                                    <gmd:dateType gco:nilReason="missing" />
+                                </gmd:CI_Date>
+                            </gmd:date>
+                        </gmd:CI_Citation>
+                    </gmd:thesaurusName>
+                </gmd:MD_Keywords>
+            </gmd:descriptiveKeywords>
+            <gmd:resourceConstraints>
+                <gmd:MD_LegalConstraints>
+                    <gmd:accessConstraints>
+                        <gmd:MD_RestrictionCode
+                            codeList="http://www.isotc211.org/2005/resources/Codelist/gmxCodelists.xml#MD_RestrictionCode"
+                            codeSpace="ISOTC211/19115" codeListValue="otherRestrictions">otherRestrictions</gmd:MD_RestrictionCode>
+                    </gmd:accessConstraints>
+                </gmd:MD_LegalConstraints>
+            </gmd:resourceConstraints>
+            <gmd:spatialRepresentationType>
+                <gmd:MD_SpatialRepresentationTypeCode
+                    codeList="http://www.isotc211.org/2005/resources/Codelist/gmxCodelists.xml#MD_SpatialRepresentationTypeCode"
+                    codeSpace="ISOTC211/19115" codeListValue="POINT">POINT</gmd:MD_SpatialRepresentationTypeCode>
+            </gmd:spatialRepresentationType>
+            <gmd:language>
+                <gmd:LanguageCode codeList="http://www.loc.gov/standards/iso639-2/"
+                    codeSpace="ISO 639-2" codeListValue="eng">eng</gmd:LanguageCode>
+            </gmd:language>
+            <gmd:characterSet>
+                <gmd:MD_CharacterSetCode
+                    codeList="http://www.isotc211.org/2005/resources/Codelist/gmxCodelists.xml#MD_CharacterSetCode"
+                    codeSpace="ISOTC211/19115" codeListValue="utf8">utf8</gmd:MD_CharacterSetCode>
+            </gmd:characterSet>
+            <gmd:topicCategory>
+                <gmd:MD_TopicCategoryCode>geoscientificInformation</gmd:MD_TopicCategoryCode>
+            </gmd:topicCategory>
+
+            <gmd:extent><!-- empty extent element -->
+            </gmd:extent>
+            <gmd:extent><!-- box without coords -->
+                <gmd:EX_Extent>
+                    <gmd:geographicElement>
+                        <gmd:EX_GeographicBoundingBox />
+                    </gmd:geographicElement>
+                </gmd:EX_Extent>
+            </gmd:extent>
+            <gmd:extent>
+                <gmd:EX_Extent>
+                    <gmd:geographicElement>
+                        <gmd:EX_GeographicBoundingBox>
+                            <gmd:extentTypeCode>
+                                <gco:Boolean>1</gco:Boolean>
+                            </gmd:extentTypeCode>
+                            <gmd:westBoundLongitude>
+                                <gco:Decimal>21.0558004086</gco:Decimal>
+                            </gmd:westBoundLongitude>
+                            <gmd:eastBoundLongitude>
+                                <gco:Decimal>28.1767094256</gco:Decimal>
+                            </gmd:eastBoundLongitude>
+                            <gmd:southBoundLatitude>
+                                <gco:Decimal>55.61510692</gco:Decimal>
+                            </gmd:southBoundLatitude>
+                            <gmd:northBoundLatitude>
+                                <gco:Decimal>57.9701569688</gco:Decimal>
+                            </gmd:northBoundLatitude>
+                        </gmd:EX_GeographicBoundingBox>
+                    </gmd:geographicElement>
+                </gmd:EX_Extent>
+            </gmd:extent>
+            <gmd:extent><!-- no period -->
+                <gmd:EX_Extent>
+                    <gmd:temporalElement />
+                </gmd:EX_Extent>
+            </gmd:extent>
+            <gmd:extent>
+                <gmd:EX_Extent><!-- half period -->
+                    <gmd:temporalElement>
+                        <gmd:EX_TemporalExtent>
+                            <gmd:extent>
+                                <gml:TimePeriod>
+                                    <gml:beginPosition>2005-11-03</gml:beginPosition>
+                                    <gml:endPosition>2008-05-12</gml:endPosition>
+                                </gml:TimePeriod>
+                            </gmd:extent>
+                        </gmd:EX_TemporalExtent>
+                    </gmd:temporalElement>
+                </gmd:EX_Extent>
+            </gmd:extent>
+            <gmd:extent><!-- no period -->
+                <gmd:EX_Extent>
+                    <gmd:temporalElement>
+                        <gmd:EX_TemporalExtent>
+                            <gmd:extent>
+                                <gml:TimePeriod />
+                            </gmd:extent>
+                        </gmd:EX_TemporalExtent>
+                    </gmd:temporalElement>
+                </gmd:EX_Extent>
+            </gmd:extent>
+            <gmd:extent>
+                <gmd:EX_Extent><!-- half period -->
+                    <gmd:temporalElement>
+                        <gmd:EX_TemporalExtent>
+                            <gmd:extent>
+                                <gml:TimePeriod>
+                                    <gml:beginPosition>2005</gml:beginPosition>
+                                    <gml:endPosition />
+                                </gml:TimePeriod>
+                            </gmd:extent>
+                        </gmd:EX_TemporalExtent>
+                    </gmd:temporalElement>
+                </gmd:EX_Extent>
+            </gmd:extent>
+        </gmd:MD_DataIdentification>
+    </gmd:identificationInfo>
+    <gmd:distributionInfo>
+        <gmd:MD_Distribution>
+            <gmd:transferOptions>
+                <gmd:MD_DigitalTransferOptions>
+                    <gmd:onLine>
+                        <gmd:CI_OnlineResource>
+                            <gmd:linkage>
+                                <gmd:URL>
+                                    https://github.com/ejpsoil/ejpsoildatahub/tree/main/datasets/countries/Latvia/Database-on-the-monitoring-of-mi.yml</gmd:URL>
+                            </gmd:linkage>
+                            <gmd:protocol>
+                                <gco:CharacterString>canonical</gco:CharacterString>
+                            </gmd:protocol>
+                            <gmd:name>
+                                <gco:CharacterString>Source of the record</gco:CharacterString>
+                            </gmd:name>
+                            <gmd:function>
+                                <gmd:CI_OnLineFunctionCode
+                                    codeList="https://www.iana.org/assignments/link-relations/link-relations.xml"
+                                    codeSpace="rfc8288" codeListValue="canonical">canonical</gmd:CI_OnLineFunctionCode>
+                            </gmd:function>
+                        </gmd:CI_OnlineResource>
+                    </gmd:onLine>
+                </gmd:MD_DigitalTransferOptions>
+            </gmd:transferOptions>
+        </gmd:MD_Distribution>
+    </gmd:distributionInfo>
+    <gmd:dataQualityInfo>
+        <gmd:DQ_DataQuality>
+            <gmd:scope>
+                <gmd:DQ_Scope>
+                    <gmd:level>
+                        <gmd:MD_ScopeCode
+                            codeList="http://www.isotc211.org/2005/resources/Codelist/gmxCodelists.xml#MD_ScopeCode"
+                            codeSpace="ISOTC211/19115" codeListValue="dataset">dataset</gmd:MD_ScopeCode>
+                    </gmd:level>
+                </gmd:DQ_Scope>
+            </gmd:scope>
+            <gmd:lineage>
+                <gmd:LI_Lineage>
+                    <gmd:statement>
+                        <gco:CharacterString>Topsoil and subsoil sampling. Mapping: . Depth
+                            intervals: Other depth intervals (specify in comments). Uncertainty
+                            quantification: NO</gco:CharacterString>
+                    </gmd:statement>
+                </gmd:LI_Lineage>
+            </gmd:lineage>
+        </gmd:DQ_DataQuality>
+    </gmd:dataQualityInfo>
+    <gmd:metadataMaintenance>
+        <gmd:MD_MaintenanceInformation>
+            <gmd:maintenanceAndUpdateFrequency>
+                <gmd:MD_MaintenanceFrequencyCode
+                    codeList="http://www.isotc211.org/2005/resources/Codelist/gmxCodelists.xml#MD_MaintenanceFrequencyCode"
+                    codeSpace="ISOTC211/19115" codeListValue="regular monitoring, yearly">regular monitoring, yearly</gmd:MD_MaintenanceFrequencyCode>
+            </gmd:maintenanceAndUpdateFrequency>
+        </gmd:MD_MaintenanceInformation>
+    </gmd:metadataMaintenance>
+</gmd:MD_Metadata>
\ No newline at end of file
diff --git a/tests/run_tests.py b/tests/run_tests.py
index 3ceb6c0..64ac926 100644
--- a/tests/run_tests.py
+++ b/tests/run_tests.py
@@ -460,6 +460,24 @@ def test_import_metadata(self):
                 'WIS/GTS bulletin SMJP01 RJTD in FM12 SYNOP',
                 'Expected specific title')
 
+    def test_empty_extents(self):
+        # do not fail on empty elements
+        schema = ISO19139OutputSchema()
+        with open(get_abspath('iso19139-no-bbox.xml')) as fh:
+            # owslib selects the first EX_GeographicBoundingBox,
+            # so if it is empty, it will not check others
+            mcf = schema.import_(fh.read())
+            self.assertEqual(
+                len(mcf['identification']['extents']['spatial'][0]['bbox']),
+                0,
+                'empty box')
+            # owslib selects first beginPosition element,
+            # so it skips empty temporalElements
+            self.assertEqual(
+                mcf['identification']['extents']['temporal'][0]['begin'],
+                '2005-11-03',
+                'assert date, skip empty period')
+
     def test_transform_metadata(self):
         """test metadata transform"""