<?xml version="1.0" encoding="UTF-8"?>
<!-- edited with XMLSpy v2005 rel. 3 U (http://www.altova.com) by Todd Billings (ENVIRONMENT CANADA) -->
<xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema" elementFormDefault="qualified" attributeFormDefault="unqualified">
	<xsd:include schemaLocation="measurement.xsd"/>
	<xsd:complexType name="observationType">
		<xsd:choice maxOccurs="unbounded">
			<xsd:element name="pressure" type="pressureObsType"/>
			<xsd:element name="wind" type="windObsType"/>
			<xsd:element name="temperature" type="temperatureObsType"/>
			<xsd:element name="precipitation" type="precipitationObsType"/>
			<xsd:element name="radiation" type="radiationObsType"/>
			<xsd:element name="visibility" type="visibilityObsType"/>
			<xsd:element name="pavement" type="pavementObsType"/>
			<xsd:element name="subsurface" type="subsurfaceObsType"/>
			<xsd:element name="air-quality" type="air-qualityObsType"/>
			<xsd:element name="physical-status" type="physical-statusObsType"/>
			<xsd:element name="humidity" type="humidityObsType"/>
			<xsd:element name="weather" type="weatherObsType"/>
			<xsd:element name="snow" type="snowObsType"/>
			<xsd:element name="snapshot-camera" type="snapshot-cameraObsType"/>
			<xsd:element name="extension" type="measurementType"/>
		</xsd:choice>
		<xsd:attribute name="valid-time" type="xsd:dateTime" use="required"/>
	</xsd:complexType>
</xsd:schema>
