<?xml version="1.0" encoding="UTF-8"?>
<xsd:schema xmlns="http://water.usgs.gov/XML/AQ" xmlns:xsd="http://www.w3.org/2001/XMLSchema" targetNamespace="http://water.usgs.gov/XML/AQ" elementFormDefault="qualified" version="1.0">
   <xsd:simpleType name="HexValueType">
      <xsd:restriction base="xsd:string">
         <xsd:pattern value="[0-9A-F]+"/>
         <xsd:minLength value="8"/>
         <xsd:maxLength value="8"/>
      </xsd:restriction>
   </xsd:simpleType>
</xsd:schema>