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Developing an Open Source AIXM5 Java Library (AIXM-J)

Developing an Open Source AIXM5 Java Library (AIXM-J). Steven Chase Lead Software Engineer MITRE/CAASD March 19, 2008. Overview. Background Tools Data sources Open source project Goals Technology Challenges Status Using the library Demo. MITRE/CAASD Background.

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Developing an Open Source AIXM5 Java Library (AIXM-J)

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  1. Developing an Open Source AIXM5 Java Library(AIXM-J) Steven Chase Lead Software Engineer MITRE/CAASD March 19, 2008

  2. Overview • Background • Tools • Data sources • Open source project • Goals • Technology • Challenges • Status • Using the library • Demo

  3. MITRE/CAASD Background • The MITRE Corporation • Private, independent, not-for-profit organization • Chartered to work in the public interest • CAASD • Federally Funded Research & Development Center (FFRDC) operated by MITRE • Provides systems research and development for the Federal Aviation Administration (FAA) and international civil aviation authorities

  4. Procedure design, flyability, simulation, visualization ILS approach/airport safety analysis, CRM CAASD Developed Tools Safety Assessment Toolset TARGETS

  5. Data Sources • National Flight Data Center (NFDC/NASR) • AVN Information Services (AVNIS) • Jeppesen • National Aeronautical Charting Office (NACO) • Digital Aeronautical Flight Information File (DAFIF) • Digital Obstacle File (DOF) • Elevation Data (DEM, DTED, etc)

  6. Goals • Develop AIXM5 Java library that is: • Independent • Easy to use • Well documented • Extensible • AIXM5 compliant • Enable applications to read/write AIXM5 data • Handle large data sets

  7. Technology • Sun JDK (5 or greater) • Enum, generics, enhanced for loop, etc. • Dom4j • Library for using XML, XPath (jaxen) and XSLT • Full support for DOM, SAX and JAXP • Easy, fast, open source • Why not use JAXB or XMLBeans? • In early versions, not all AIXM5 schema elements and attributes were supported • Auto-generated code may be hard to work with • Other attempts have been made

  8. Challenges • Understanding the model • Model is still changing • Sample XML is limited • Implementing GML

  9. Status • Features • AirportHeliport • Runway • Navaid • Designated Point • Vertical Structure • STAR/SID • Basic Message • GML Point and ValidTime <aixm:VerticalStructure xmlns:aixm="http://www.aixm.aero/schema/5.0" gml:id="19608436"> <aixm:timeSlice> <aixm:VerticalStructureTimeSlice gml:id="26795951"> <aixm:name>TEST OBSTACLE</aixm:name> <aixm:type>POLE</aixm:type> <aixm:constructionStatus>COMPLETED</aixm:constructionStatus> <aixm:material>STEEL</aixm:material> <aixm:markingPattern>STEEL</aixm:markingPattern> <aixm:markingFirstColour>RED</aixm:markingFirstColour> <aixm:markingSecondColour>BLACK</aixm:markingSecondColour> <aixm:markingICAOStandard>YES</aixm:markingICAOStandard> <aixm:group>NO</aixm:group> <aixm:isMadeOf> <aixm:VerticalStructurePart gml:id="25276323"> <aixm:verticalExtent uom="FT">500.0</aixm:verticalExtent> <aixm:verticalExtentAccuracy uom="FT">10.0</aixm:verticalExtentAccuracy> <aixm:hasPointShape> <aixm:ElevatedPoint gml:id="20051738"> <gml:pos>70.0 -122.0</gml:pos> <aixm:elevation uom="FT">1500.0</aixm:elevation> <aixm:geoidUndulation uom="M">212.0</aixm:geoidUndulation> <aixm:verticalDatum>EGM96</aixm:verticalDatum> <aixm:horizontalAccuracy uom="M">15.0</aixm:horizontalAccuracy> <aixm:verticalAccuracy uom="M">10.0</aixm:verticalAccuracy> </aixm:ElevatedPoint> </aixm:hasPointShape> </aixm:VerticalStructurePart> </aixm:isMadeOf> </aixm:VerticalStructureTimeSlice> </aixm:timeSlice> </aixm:VerticalStructure> Sample XML – Vertical Structure

  10. Status (ctd) • Includes sample programs that read/write AIXM5 • XML has not been validated • Uses GNU General Public License (GPL) • Hosted on Sourceforge • http://sourceforge.net/projects/aixm-j

  11. Using the Library • Add aixm-j, dom4j, jaxen jar files to classpath AIXM-J Library Objects AIXM5 XML Your Application Aviation Objects Convert to AIXM-J Objects dom4j Generating AIXM5 XML

  12. Demo © 2008 The MITRE Corporation. All rights reserved. 12 Document Number Here

  13. Sample Code/Notes © 2008 The MITRE Corporation. All rights reserved. 14

  14. Sample Conversion Method // Takes an Airport object and returns an AixmFeature object public static AixmFeature createAixmAirport(Airport airport) { // create an AixmFeature object AixmFeature ah = new AixmFeature(AixmFeatureType.AirportHeliport); // create an AixmAirportHeliportTimeSlice AixmAirportHeliportTimeSlice timeSlice = new AixmAirportHeliportTimeSlice(); // set gmlId timeSlice.setGmlId(String.valueOf(airport.getUniqueKey())); // set designator timeSlice.setDesignator(airport.getAirportId()); // set elevation AixmVerticalDistanceValue fieldElevation = new AixmVerticalDistanceValue(airport.getElevation(), AixmUomDistanceVerticalType.FT); timeSlice.setFieldElevation(fieldElevation); // set rest of fields here… // add the timeSlice to AirportHeliport ah.addTimeSlice(timeSlice); // return the AixmFeature object return ah; }

  15. Generating AIXM5 XML // Convert airport to AixmFeature object AixmFeature aixmAirport = AixmAirportUtil.createAixmAirport(airport); // Create dom4j Document Document document = DocumentHelper.createDocument(); // Create the root Element QName qname = QName.get(“AirportHeliport”, AixmConstants.AIXM_NAMESPACE); Element rootElement = DocumentHelper.createElement(qname); // Set the root Element, XPath won’t work until you do this document.setRootElement(element); // Call AIXM-J method to add dom4j Elements to represent the airport aixmAirport.addElements(rootElement, document); // Pretty print the document OutputFormat formatter = OutputFormat.createPrettyPrint(); try { XMLWriter writer = new XMLWriter(System.out, formatter); writer.write(document); writer.flush(); } catch (Exception ex) { ex.printStackTrace(); }

  16. Generated XML <?xml version="1.0" encoding="UTF-8"?> <aixm:AirportHeliport xmlns:aixm="http://www.aixm.aero/schema/5.0" xmlns:gml="http://www.opengis.net/gml" xmlns:xlink="http://www.w3.org/1999/xlink" gml:id="org.mitre.caasd.aixm.feature.airportheliport.airportheliport.AixmAirportHeliport6468511"> <aixm:timeSlice> <aixm:AirportHeliportTimeSlice gml:id="1576249658"> <aixm:designator>KIAD</aixm:designator> <aixm:name>WASHINGTON DULLES INTL</aixm:name> <aixm:locationIndicatorICAO>K6KIAD</aixm:locationIndicatorICAO> <aixm:type>AD</aixm:type> <aixm:private>NO</aixm:private> <aixm:elevation uom="FT">313.0</aixm:elevation> <aixm:serves> <aixm:City gml:id="org.mitre.caasd.aixm.data.AixmCity15925147"> <aixm:name>WASHINGTON</aixm:name> </aixm:City> </aixm:serves> <aixm:magneticVariation>-10.0</aixm:magneticVariation> <aixm:dateMagneticVariation>2000</aixm:dateMagneticVariation> <aixm:hasReferencePoint> <aixm:ElevatedPoint xmlns:aixm="http://www.aixm.aero" gml:id="23811352"> <gml:pos>38.94453194444444 -77.45580972222223</gml:pos> <aixm:elevation uom="FT">313.0</aixm:elevation> </aixm:ElevatedPoint> </aixm:hasReferencePoint> …

  17. Parsing an AIXM5 ILS File // Open the file, create a BufferedReader and SAXReader FileInputStream is = new FileInputStream(new File("ILS.aixm.xml")); BufferedReader br = new BufferedReader(new InputStreamReader(is)); SAXReader saxReader = new SAXReader(); // Add handler for each Navaid tag saxReader.addHandler("/ils-subscriber-file/Navaid", new ElementHandler() { public void onEnd(ElementPath path) { Element navaidElement = path.getCurrent(); // Convert the dom4j Element to an AixmFeature object AixmFeature navaid = new AixmFeature(AixmFeatureType.Navaid).parseElements(navaidElement); // Do something with the data here, in this example we just print the object System.out.println("navaid : " + navaid); // Free up memory navaidElement.detach(); } public void onStart(ElementPath path) {/* do nothing */} } ); // Read the XML file saxReader.read(br);

  18. Notes • AIXM – Aeronautical Information Exchange Model (AIXM) is designed to enable the management and distribution of Aeronautical Information Services (AIS) data in digital format • XMLBeans – XMLBeans is a technology for accessing XML by binding it to Java types • JDK – Java Development Kit, includes Java compiler, runtime environment, etc. • JAXB – The Java Architecture for XML Binding • SAX – Simple API for XML (SAX) is a serial access parser API for XML; event driven; user defines callback methods that are called during parsing • DOM – Document Object Model (DOM) is a standard object model for representing XML formats; tree based model • JAXP – Java API for XML Processing • XPath – Xml Path (XPath) is a language for selecting nodes from an XML document • Jaxen – Java XPath Engine (Jaxen) is an open source XPath library for Java • Dom4j – dom4j is an easy to use, open source library for working with XML, XPath and XSLT • XSLT – Extensible Stylesheet Language Transformations (XSLT) is a language for transforming XML documents into other XML documents

  19. Notes (ctd) • CAASD – Center for Advanced Aviation System Development, operated by MITRE • TARGETS – Terminal Area Route Generation, Evaluation and Traffic Simulation • ILS – Instrument Landing System • CRM – Collision Risk Model • DEM – Digital Elevation Model • DTED – Digital Terrain Elevation Data • NASR – National Airspace System Resources

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