<?xml version='1.0' encoding='UTF-8'?>

<!--
    TODO define vocabulary identification
    PUBLIC ID: -//vendor//vocabulary//EN
    SYSTEM ID: http://server/path/felt_variables.dtd

--><!--
    An example how to use this DTD from your XML document:

    <?xml version="1.0"?>

    <!DOCTYPE variables SYSTEM "felt_variables.dtd">

    <variables>
    ...
    </variables>
-->

<!--- Put your DTDDoc comment here. -->
<!ELEMENT variables (parameter)*>

<!--- Put your DTDDoc comment here. -->
<!ELEMENT parameter (attribute|spatial_vector)*>
<!ATTLIST parameter
    type CDATA #IMPLIED
    name CDATA #REQUIRED
    id CDATA #REQUIRED
  >

<!--- Put your DTDDoc comment here. -->
<!ELEMENT attribute EMPTY>
<!ATTLIST attribute
    type CDATA #REQUIRED
    value CDATA #REQUIRED
    name CDATA #REQUIRED
  >

<!--- Put your DTDDoc comment here. -->
<!ELEMENT spatial_vector EMPTY>
<!ATTLIST spatial_vector
    direction CDATA #REQUIRED
    counterpart CDATA #REQUIRED
  >
  