Sitemap XML validator: check urlset against XSD

<?xml version="1.0" encoding="UTF-8"?>
<xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema"
            targetNamespace="http://www.sitemaps.org/schemas/sitemap/0.9"
            xmlns="http://www.sitemaps.org/schemas/sitemap/0.9"
            elementFormDefault="qualified">
  <xsd:annotation>
    <xsd:documentation>
      XML Schema for Sitemap files.
      Last Modifed 2008-03-26
    </xsd:documentation>
  </xsd:annotation>

  <xsd:element name="urlset">
    <xsd:annotation>
      <xsd:documentation>
        Container for a set of up to 50,000 document elements.
        This is the root element of the XML file.
      </xsd:documentation>
    </xsd:annotation>
    <xsd:complexType>
      <xsd:sequence>
        <xsd:any namespace="##other" minOccurs="0" maxOccurs="unbounded" processContents="strict"/>
        <xsd:element name="url" type="tUrl" maxOccurs="unbounded"/>
      </xsd:sequence>
    </xsd:complexType>
  </xsd:element>

  <xsd:complexType name="tUrl">
    <xsd:annotation>
      <xsd:documentation>
        Container for the data needed to describe a document to crawl.
      </xsd:documentation>
    </xsd:annotation>
    <xsd:sequence>
      <xsd:element name="loc" type="tLoc"/>
      <xsd:element name="lastmod" type="tLastmod" minOccurs="0"/>
      <xsd:element name="changefreq" type="tChangeFreq" minOccurs="0"/>
      <xsd:element name="priority" type="tPriority" minOccurs="0"/>
      <xsd:any namespace="##other" minOccurs="0" maxOccurs="unbounded" processContents="strict"/>
    </xsd:sequence>
  </xsd:complexType>

  <xsd:simpleType name="tLoc">
    <xsd:annotation>
      <xsd:documentation>
        REQUIRED: The location URI of a document.
        The URI must conform to RFC 2396 (http://www.ietf.org/rfc/rfc2396.txt).
      </xsd:documentation>
    </xsd:annotation>
    <xsd:restriction base="xsd:anyURI">
      <xsd:minLength value="12"/>
      <xsd:maxLength value="2048"/>
    </xsd:restriction>
  </xsd:simpleType>

  <xsd:simpleType name="tLastmod">
    <xsd:annotation>
      <xsd:documentation>
        OPTIONAL: The date the document was last modified. The date must conform
        to the W3C DATETIME format (http://www.w3.org/TR/NOTE-datetime).
        Example: 2005-05-10
        Lastmod may also contain a timestamp.
        Example: 2005-05-10T17:33:30+08:00
      </xsd:documentation>
    </xsd:annotation>
    <xsd:union>
      <xsd:simpleType>
        <xsd:restriction base="xsd:date"/>
      </xsd:simpleType>
      <xsd:simpleType>
        <xsd:restriction base="xsd:dateTime"/>
      </xsd:simpleType>
    </xsd:union>
  </xsd:simpleType>

  <xsd:simpleType name="tChangeFreq">
    <xsd:annotation>
      <xsd:documentation>
        OPTIONAL: Indicates how frequently the content at a particular URL is
        likely to change. The value "always" should be used to describe
        documents that change each time they are accessed. The value "never"
        should be used to describe archived URLs. Please note that web
        crawlers may not necessarily crawl pages marked "always" more often.
        Consider this element as a friendly suggestion and not a command.
      </xsd:documentation>
    </xsd:annotation>
    <xsd:restriction base="xsd:string">
      <xsd:enumeration value="always"/>
      <xsd:enumeration value="hourly"/>
      <xsd:enumeration value="daily"/>
      <xsd:enumeration value="weekly"/>
      <xsd:enumeration value="monthly"/>
      <xsd:enumeration value="yearly"/>
      <xsd:enumeration value="never"/>
    </xsd:restriction>
  </xsd:simpleType>

  <xsd:simpleType name="tPriority">
    <xsd:annotation>
      <xsd:documentation>
        OPTIONAL: The priority of a particular URL relative to other pages
        on the same site. The value for this element is a number between
        0.0 and 1.0 where 0.0 identifies the lowest priority page(s).
        The default priority of a page is 0.5. Priority is used to select
        between pages on your site. Setting a priority of 1.0 for all URLs
        will not help you, as the relative priority of pages on your site
        is what will be considered.
      </xsd:documentation>
    </xsd:annotation>
    <xsd:restriction base="xsd:decimal">
      <xsd:minInclusive value="0.0"/>
      <xsd:maxInclusive value="1.0"/>
    </xsd:restriction>
  </xsd:simpleType>

</xsd:schema>