Using xmlread and Document object model to get data from xml files

The following is an xml example file that we are trying to read using xmlread. Apparently xmlread converts the data into Document object model (DOM). I have searched in google and found some examples which use xmlread in matlab to get the data from xml files. But, they used very simple xml files, while the one I am using is very complex and the structure dynamically changes.

I basically want to extract some information from this xml file. For example:

1. What is the id name in the header (Ans: IED15)

2. What is the SubNetwork name? (Ans: Subnet2)

I have attached a minimum working example that I use right now. I am looking for syntax like "xRoot.getAttribute" which help me to get the information from the xml file.

Thanks in advance.

 < %%Minimum working example in Matlab
xDoc = xmlread(xmlfile);
xRoot = xDoc.getDocumentElement;
xmlns_xsi = ...
   char(xRoot.getAttribute('xmlns:xsi'))
id = ...
   char(xRoot.getAttribute('xsi:noNamespaceSchemaLocation'))
%------------------------------------------------------------>

href = ""<SCL xmlns:xsi="C:\Users\Schema Defintion\xml schema test.xsd" xsi:noNamespaceSchemaLocation="http://www.mathworks.com/namespace/info/v1/info.xsd"</a>

<Header id="IED15" nameStructure="IEDName" revision="R 001" toolID="Manual" version="">
  <History>
    <Hitem revision="R 001" version="V 0.0" what="test" when="Tue Jun 09 10:19:00 EDT 2015" who="wdk" why=""/>
  </History>
</Header>
<Communication>
  <SubNetwork name="Subnet2" type="8-MMS">
    <ConnectedAP apName="AP15" iedName="IED15">
      <Address>
        <P type="IP">192.168.48.15</P>
        <P type="OSI-AP-Title">1,3,9999,23</P>
        <P type="IP-SUBNET">255.255.255.0</P>
        <P type="OSI-AE-Qualifier">15</P>
      <P type="OSI-AP-Invoke">10</P>
        <P type="OSI-AE-Invoke">10</P>
        <P type="OSI-PSEL">00000001</P>
        <P type="OSI-SSEL">0001</P>
        <P type="OSI-TSEL">0001</P>
      </Address>
      <PhysConn type="Connection">
        <P type="Type"> 100BaseT</P>
      </PhysConn>
    </ConnectedAP>
  </SubNetwork>
</Communication>
<IED name="IED15" configVersion="1.0" manufacturer="UTK" type="Default">
  <AccessPoint name="AP15">
    <Server>
      <Authentication none="true"/>
      <LDevice inst="L1">
        <LN0 lnType="lln0_node" inst="" lnClass="LLN0"/>
        <LN lnType="lphd_node" inst="1" lnClass="LPHD"/>
        <LN lnType="mmxu_node" inst="1" lnClass="MMXU"/>
      <LN lnType="drcc_node" inst="1" lnClass="DRCC"/>
      <LN lnType="zbat_node" inst="1" lnClass="ZBAT"/>
      </LDevice>
    </Server>
  </AccessPoint>
</IED>
<DataTypeTemplates>
  <LNodeType id="lphd_node" lnClass="LPHD">
    <DO accessControl="" name="PhyHealth" type="INS" transient="false"/>
    <DO accessControl="" name="Proxy" type="SPS" transient="false"/>
  </LNodeType>
  <LNodeType id="mmxu_node" lnClass="MMXU">
    <DO accessControl="" name="PhV" type="WYE" transient="false"/>
    <DO accessControl="" name="W" type="WYE" transient="false"/>
    <DO accessControl="" name="VAr" type="WYE" transient="false"/>
  </LNodeType>
  <LNodeType id="drcc_node" lnClass="DRCC">
    <DO accessControl="" name="OutWSet" type="APC" transient="false"/>
    <DO accessControl="" name="OutVarSet" type="APC" transient="false"/>
    <DO accessControl="" name="DERStr" type="SPC" transient="false"/>
    <DO accessControl="" name="DERStop" type="SPC" transient="false"/>
    <DO accessControl="" name="AutoManCtl" type="SPC" transient="false"/>
    <DO accessControl="" name="LocRemCtl" type="SPC" transient="false"/>
  </LNodeType>
  <LNodeType id="zbat_node" lnClass="ZBAT">
    <DO accessControl="" name="BatSt" type="SPS" transient="false"/>
    <DO accessControl="" name="BatTestRsl" type="SPS" transient="false"/>
    <DO accessControl="" name="BatVHi" type="SPS" transient="false"/>
    <DO accessControl="" name="BatVLo" type="SPS" transient="false"/>
    <DO accessControl="" name="BatTyp" type="ENG_BatTyp" transient="false"/>
    <DO accessControl="" name="AhrRtg" type="ASG" transient="false"/>
    <DO accessControl="" name="MinAhrRtg" type="ASG" transient="false"/>
    <DO accessControl="" name="BatVNom" type="ASG" transient="false"/>
    <DO accessControl="" name="BatSerCnt" type="ING" transient="false"/>
    <DO accessControl="" name="BatParCnt" type="ING" transient="false"/>
    <DO accessControl="" name="DisChaRte" type="ASG" transient="false"/>
    <DO accessControl="" name="MaxBatA" type="ASG" transient="false"/>
    <DO accessControl="" name="MaxChaV" type="ASG" transient="false"/>
    <DO accessControl="" name="HiBatVAlm" type="ASG" transient="false"/>
    <DO accessControl="" name="LoBatVAlm" type="ASG" transient="false"/>
    <DO accessControl="" name="Vol" type="MV" transient="false"/>
    <DO accessControl="" name="VolChgRte" type="MV" transient="false"/>
    <DO accessControl="" name="InBatV" type="MV" transient="false"/>
    <DO accessControl="" name="Amp" type="MV" transient="false"/>
    <DO accessControl="" name="InBatA" type="MV" transient="false"/>
    <DO accessControl="" name="InBatTmp" type="MV" transient="false"/>
    <DO accessControl="" name="BatOn" type="SPC" transient="false"/>
    <DO accessControl="" name="BatTest" type="SPC" transient="false"/>
  </LNodeType>
  <LNodeType id="lln0_node" lnClass="LLN0">
    <DO accessControl="" name="Mod" type="INC" transient="false"/>
    <DO accessControl="" name="Beh" type="INS" transient="false"/>
    <DO accessControl="" name="Loc" type="SPS" transient="false"/>
  </LNodeType>
  <DOType id="APC" cdc="APC">
    <DA bType="Struct" name="setMag" type="AnalogueValue" fc="SP"/>
    <DA bType="Quality" name="q" type="" fc="ST" qchg="true"/>
    <DA bType="Timestamp" name="t" type="" fc="ST"/>
    <DA bType="Enum" name="ctlModel" type="ctlModel" fc="CF"/>
  </DOType>
  <DOType id="ASG" cdc="ASG">
    <DA bType="Struct" name="setMag" type="AnalogueValue" fc="SP"/>
  </DOType>
  <DOType id="ENG_BatTyp" cdc="ENG">
    <DA bType="Enum" name="stVal" type="BatTyp" fc="SP"/>
  </DOType>
  <DOType id="INC" cdc="INC">
    <DA bType="INT32" name="ctlVal" type="" fc="CO"/>
    <DA bType="INT32" name="stVal" type="" dchg="true" fc="ST"/>
    <DA bType="Quality" name="q" type="" fc="ST" qchg="true"/>
    <DA bType="Timestamp" name="t" type="" fc="ST"/>
    <DA bType="Enum" name="ctlModel" type="ctlModel" fc="CF"/>
  </DOType>
  <DOType id="ING" cdc="ING">
    <DA bType="INT32" name="setVal" type="" fc="SP"/>
  </DOType>
  <DOType id="INS" cdc="INS">
    <DA bType="INT32" name="stVal" type="" dchg="true" fc="ST"/>
    <DA bType="Quality" name="q" type="" fc="ST" qchg="true"/>
    <DA bType="Timestamp" name="t" type="" fc="ST"/>
  </DOType>
  <DOType id="SPC" cdc="SPC">
    <DA bType="BOOLEAN" name="ctlVal" type="" fc="CO"/>
    <DA bType="Quality" name="q" type="" fc="ST" qchg="true"/>
    <DA bType="Timestamp" name="t" type="" fc="ST"/>
    <DA bType="Enum" name="ctlModel" type="ctlModel" fc="CF"/>
  </DOType>
  <DOType id="SPS" cdc="SPS">
    <DA bType="BOOLEAN" name="stVal" type="" dchg="true" fc="ST"/>
    <DA bType="Quality" name="q" type="" fc="ST" qchg="true"/>
    <DA bType="Timestamp" name="t" type="" fc="ST"/>
  </DOType>
  <DOType id="CMV" cdc="CMV">
    <DA bType="Struct" name="cVal" type="Vector" dchg="true" fc="MX"/>
    <DA bType="Quality" name="q" type="" fc="MX" qchg="true"/>
    <DA bType="Timestamp" name="t" type="" fc="MX"/>
  </DOType>
  <DOType id="MV" cdc="MV">
    <DA name="instMag" bType="Struct" type="AnalogueValue" fc="MX"/>
    <DA name="mag" bType="Struct" type="AnalogueValue" dchg="true" fc="MX"/>
    <DA bType="Quality" name="q" type="" fc="MX" qchg="true"/>
    <DA bType="Timestamp" name="t" type="" fc="MX"/>
  </DOType>
  <DOType id="WYE" cdc="WYE">
    <SDO name="phsA" type="CMV"/>
    <SDO name="phsB" type="CMV"/>
    <SDO name="phsC" type="CMV"/>
  </DOType>
  <DOType id="INC" cdc="INC">
    <DA bType="INT32" name="stVal" type="" dchg="true" fc="ST"/>
    <DA bType="Quality" name="q" type="" fc="ST" qchg="true"/>
    <DA bType="Timestamp" name="t" type="" fc="ST"/>
  </DOType>
  <DAType id="Vector">
    <BDA bType="Struct" name="mag" type="AnalogueValue"/>
  </DAType>
  <DAType id="AnalogueValue">
    <BDA name="f" bType="FLOAT32" />
  </DAType>
  <EnumType id="ctlModel">
    <EnumVal ord="0">status-only</EnumVal>
    <EnumVal ord="1">direct-with-normal-security</EnumVal>
    <EnumVal ord="2">sbo-with-normal-security</EnumVal>
    <EnumVal ord="3">direct-with-enhanced-security</EnumVal>
    <EnumVal ord="4">sbo-with-enhanced-security</EnumVal>
  </EnumType>
  <EnumType id="BatTyp">
    <EnumVal ord="0">Not applicable/Unknown</EnumVal>
    <EnumVal ord="1">Lead-acid</EnumVal>
    <EnumVal ord="2">Nickel-metal hydrate (NiMH)</EnumVal>
    <EnumVal ord="3">Nickel-cadmium (NiCad)</EnumVal>
    <EnumVal ord="4">Lithium</EnumVal>
    <EnumVal ord="5">Carbon zinc</EnumVal>
    <EnumVal ord="6">Zinc chloride</EnumVal>
    <EnumVal ord="7">Alkaline</EnumVal>
    <EnumVal ord="8">Rechargeable alkaline</EnumVal>
    <EnumVal ord="9">Sodium sulphur (NaS)</EnumVal>
    <EnumVal ord="10">Flow</EnumVal>
    <EnumVal ord="99">Other</EnumVal>
  </EnumType>
</DataTypeTemplates>
</SCL>
>

Answer 1

[Kelly Kearney]

The DOM format is definitely not intuitive for someone without much object-oriented experience (like me), but I've found I can usually get the basics out of it using getElementsByTagName, recursing down if necessary. For your case,

xdoc = xmlread('test.xml');
header = xdoc.getElementsByTagName('Header');

id = char(header.item(0).getAttribute('id'));

com = xdoc.getElementsByTagName('Communication');
sub = com.item(0).getElementsByTagName('SubNetwork');

subname = char(sub.item(0).getAttribute('name'));

produces:

id =

IED15

subname =

Subnet2

[Kumar]

Thank you. This worked well.

Answer 2

[Koti Dharmateja Addala]

In addition to the above question..

How to identify '' DERStop is off type APC or SPC ".

Thanks in advance.