How to make geometry topology via XML and XSD?

Question

I need to find the way of defining lines using topology representation. Now i have something similar to it:

<?xml version="1.0" encoding="UTF-8"?>
<Root>
    <Points>
        <Point>
            <UIDP>1</UIDP>
            <X>5379847.689</X>
            <Y>1223602.644</Y>
            <MX>0.05</MX>
            <MY>0.05</MY>
        </Point>
        <Point>
            <UIDP>2</UIDP>
            <X>5379828.473</X>
            <Y>1223606.113</Y>
            <MX>0.05</MX>
            <MY>0.05</MY>
        </Point>
    </Points>
    <Lines>
        <Line>
            <Point>1</Point>/>
            <Point>2</Point>/>
        </Line>
    </Lines>  
</Root>

Where Line/Point is the value of point unique id(UIDP).

Questions

Is there any way to make it more clearly, get not only ID but hole point definition using references or something similar?
How to make it using XLink or XPointer?
How to define it in XSD Schema 1.1?

I'd be surprised if someone hasn't done this before. I like to use XML standards when I can find them and they fit. If you find one, you should find libraries as well - which means less work for you. — Kieveli, Jun 27 '16 at 13:57
Are you familiar with `.NET`? In this platform there is a `DataSet` class that allows you to define relationships between `DataTables` just as is done in databases: primary keys and foreign keys. It can automatically generate an xsd schema. If you wish, I can put the generated schema. Just specify the exact relationships between points and lines. — Alexander Petrov, Jun 27 '16 at 18:27
No i am not familiar with .NET, but it would be nice see that schema. — Roman Peresoliak, Jun 28 '16 at 09:21

score 0 · Answer 1 · answered Jun 28 '16 at 09:40

I didn't find how to make it though XLink or XPointer but uderstand how to define part of rules via XSD.

<?xml version="1.0" encoding="UTF-8"?>
<xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema"
    xmlns:vc="http://www.w3.org/2007/XMLSchema-versioning" vc:minVersion="1.1">

    <xsd:complexType name="point">
        <xsd:sequence>
            <xsd:element name="UIDP" type="xsd:integer"/>
            <xsd:element name="X" type="xsd:float"/>
            <xsd:element name="Y" type="xsd:float"/>
            <xsd:element name="MX" type="xsd:float"/>
            <xsd:element name="MY" type="xsd:float"/>
        </xsd:sequence>
    </xsd:complexType>

    <xsd:complexType name="line">
        <xsd:sequence>
            <xsd:element name="Point1" type="xsd:integer"/>
            <xsd:element name="Point2" type="xsd:integer"/>
        </xsd:sequence>
        <xsd:assert test="Point1 != Point2"/>
    </xsd:complexType>

    <xsd:element name="Root">
        <xsd:complexType>
            <xsd:sequence>

                <xsd:element name="Points">
                    <xsd:complexType>
                        <xsd:sequence>
                            <xsd:element name="Point" type="point" maxOccurs="unbounded"/>
                        </xsd:sequence>
                    </xsd:complexType>
                </xsd:element>

                <xsd:element name="Lines">
                    <xsd:complexType>
                        <xsd:sequence>
                            <xsd:element name="Line" type="line" maxOccurs="unbounded"/>      
                        </xsd:sequence>
                    </xsd:complexType>

                    <xsd:unique name="lines_unique">
                        <xsd:selector xpath="Line"/>
                        <xsd:field xpath="Point1"/>
                        <xsd:field xpath="Point2"/>
                    </xsd:unique>

                </xsd:element>
            </xsd:sequence>
        </xsd:complexType>

        <xsd:key name="point_uidp">
            <xsd:selector xpath="Points/Point"></xsd:selector>
            <xsd:field xpath="UIDP"></xsd:field>
        </xsd:key>

        <xsd:keyref refer="point_uidp" name="point_1">
            <xsd:selector xpath="Lines/Line/Point1"></xsd:selector>
            <xsd:field xpath="."></xsd:field>
        </xsd:keyref>

        <xsd:keyref refer="point_uidp" name="point_2">
            <xsd:selector xpath="Lines/Line/Point2"></xsd:selector>
            <xsd:field xpath="."></xsd:field>
        </xsd:keyref>

    </xsd:element>

</xsd:schema>

Rules defined by schema:

all of points id's have to be unique, must appear and cannot be NULL
all line point links have to be from range of points id's
line point links must be unique and cant be duplicated in other line

But one rule does not defined: sequence [1, 0] is it the same as [0, 1] — Roman Peresoliak, Jun 28 '16 at 09:42

score 0 · Answer 2 · answered Jun 29 '16 at 12:36

.NET DataSet class autogenerate following schema (I added blank lines for clarity):

<?xml version="1.0" standalone="yes"?>
<Root>
  <xs:schema id="Root" xmlns="" xmlns:xs="http://www.w3.org/2001/XMLSchema"
             xmlns:msdata="urn:schemas-microsoft-com:xml-msdata">

    <xs:element name="Root" msdata:IsDataSet="true" msdata:UseCurrentLocale="true">
      <xs:complexType>
        <xs:choice minOccurs="0" maxOccurs="unbounded">

          <xs:element name="Point">
            <xs:complexType>
              <xs:sequence>
                <xs:element name="UIDP" type="xs:int" />
                <xs:element name="X" type="xs:double" minOccurs="0" />
                <xs:element name="Y" type="xs:double" minOccurs="0" />
                <xs:element name="MX" type="xs:double" minOccurs="0" />
                <xs:element name="MY" type="xs:double" minOccurs="0" />
              </xs:sequence>
            </xs:complexType>
          </xs:element>

          <xs:element name="Line">
            <xs:complexType>
              <xs:sequence>
                <xs:element name="Point1" type="xs:int" />
                <xs:element name="Point2" type="xs:int" />
              </xs:sequence>
            </xs:complexType>
          </xs:element>

        </xs:choice>
      </xs:complexType>

      <xs:unique name="PK_Points" msdata:PrimaryKey="true">
        <xs:selector xpath=".//Point" />
        <xs:field xpath="UIDP" />
      </xs:unique>

      <xs:unique name="PK_Lines" msdata:PrimaryKey="true">
        <xs:selector xpath=".//Line" />
        <xs:field xpath="Point1" />
        <xs:field xpath="Point2" />
      </xs:unique>

      <xs:keyref name="FK_Lines2" refer="PK_Points" msdata:ConstraintOnly="true">
        <xs:selector xpath=".//Line" />
        <xs:field xpath="Point2" />
      </xs:keyref>

      <xs:keyref name="FK_Lines1" refer="PK_Points" msdata:ConstraintOnly="true">
        <xs:selector xpath=".//Line" />
        <xs:field xpath="Point1" />
      </xs:keyref>

    </xs:element>
  </xs:schema>

  <Point>
    <UIDP>1</UIDP>
    <X>5379847.689</X>
    <Y>1223602.644</Y>
    <MX>0.05</MX>
    <MY>0.05</MY>
  </Point>
  <Point>
    <UIDP>2</UIDP>
    <X>5379828.473</X>
    <Y>1223606.113</Y>
    <MX>0.05</MX>
    <MY>0.05</MY>
  </Point>

  <Line>
    <Point1>1</Point1>
    <Point2>2</Point2>
  </Line>
</Root>

The scheme is generated in a single file along with the data.

Note the absence of Points and Lines elements.

Unfortunately is the schema of version 1.0. Therefore, more advanced checks is not available.

Attributes with the msdata prefix can be removed.

How to make geometry topology via XML and XSD?

2 Answers2