15.2.47. XML Schema redefine element

Element information ¶

父元素： Schema

Grammar ¶

<redefine
id=ID
schemaLocation=anyURI
*any attributes*
>
(annotation|(simpleType|complexType|group|attributeGroup))\*
</redefine>

Attribute	Description
Id	Optional. Specifies the unique ID of the element.
SchemaLocation	Necessary. A URI reference to the location of the schema document.
Any attributes	Optional. Specifies any other attributes with the non-schema namespace.

Example 1 ¶

The following example shows a schema,Myschama2.xsd in which there are elements specified by Myschama1.xsd. The pname type is redefined. According to this schema, elements constrained by pname must end with a “country” element:

**Myschema1.xsd:**
<?xml version="1.0"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema">
<xs:complexType name="pname">
  <xs:sequence>
    <xs:element name="firstname"/>
    <xs:element name="lastname"/>
  </xs:sequence>
</xs:complexType>
<xs:element name="customer" type="pname"/>
</xs:schema>
**Myschema2.xsd:**
<?xml version="1.0"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema">
<xs:redefine schemaLocation="Myschema1.xsd">
  <xs:complexType name="pname">
    <xs:complexContent>
      <xs:extension base="pname">
        <xs:sequence>
          <xs:element name="country"/>
        </xs:sequence>
      </xs:extension>
    </xs:complexContent>
  </xs:complexType>
</xs:redefine>
<xs:element name="author" type="pname"/>
</xs:schema>

In recent years, Geographic Information Systems (GIS) have undergone rapid development in both theoretical and practical dimensions. GIS has been widely applied for modeling and decision-making support across various fields such as urban management, regional planning, and environmental remediation, establishing geographic information as a vital component of the information era. The introduction of the “Digital Earth” concept has further accelerated the advancement of GIS, which serves as its technical foundation. Concurrently, scholars have been dedicated to theoretical research in areas like spatial cognition, spatial data uncertainty, and the formalization of spatial relationships. This reflects the dual nature of GIS as both an applied technology and an academic discipline, with the two aspects forming a mutually reinforcing cycle of progress.