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Value-Added Attributes for High-Resolution NHD

Value-Added Attributes for High-Resolution NHD. NHD Stewardship Conference March 30, 2012 New Orleans, Louisiana. Josh Lear Nebraska Department of Natural Resources. Goals:. Understand how Value-Added Attributes translate to high resolution NHD Understand Value added attributes

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Value-Added Attributes for High-Resolution NHD

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  1. Value-Added Attributes for High-Resolution NHD NHD Stewardship Conference March 30, 2012 New Orleans, Louisiana Josh Lear Nebraska Department of Natural Resources

  2. Goals: • Understand how Value-Added Attributes translate to high resolution NHD • Understand Value added attributes • How they are derived • How to use them • Find a simple solution to navigating divergences

  3. Agenda • Context for discussion • Preparation and evaluation • Observations • Conclusions

  4. Subregion 1015 - Niobrara

  5. THE NAVIGATION ISSUE GNIS_ID FCode ReachCode Divergence Stream Gage Point of Diversion

  6. Value Added Attributes • FromNode/ToNode • StartFlag/TerminalFlag • VPUin/VPUout • StreamLevel • Divergence • DnDrainCount • Hydrosequence • DnLevel • UpHydroSeq/DnHydroSeq/DnMinorHydroSeq • StreamOrder/StreamCalc • LevelPathID • TerminalPathID • UplevelPathID/DnLevelPathID • PathLength • ArbolateSum • RtnDIV

  7. Navigation Determinants DNR • GNIS_ID • Fcodes • ReachCodes Value-Added Attributes • GNIS_ID • Ftype • LengthKM • + boundary information DNR relationships are local VAA relationships are system-wide

  8. Evaluation • Prepared 1015 using NHDPlus QAQC Tools • 4 Variations based on FlowDirection: • All features “WithDigitized” • Braids “Uninitialized” • Canals “Uninitialized” • Canals and braids “Uninitialized” • VAAs calculated • All Divergences evaluated for downstream navigation

  9. Preliminary Results – (AllFlow) 457 Divergences • 108 failed using the DNR approach (24%) • Not enough information • VAAs always navigated the divergence • Divergent flag • 82 Divergent flags assigned incorrectly

  10. Observations: • Errors still existed in the Flowline • Braids, Field drains • Removing braids improved VAAs • Canals -flow the wrong direction • Canals w/no returns – disconnected drains • Canal w/returns distort the VAAs significantly • Removing canals improved VAAs

  11. Canal – StreamLevel Error

  12. Observations: • Substantial agreement between methods • GNIS_ID • FCodes played a minor role • ReachCode

  13. ReachCode Miss

  14. Preliminary Conclusions: • VAAs are a superior solution • Information is the key • On the flowline • In the VAA program

  15. To Do: • Recalculate and Re-evaluate VAAs for 1015 • Configuration: • Braids, Field Drains, Canals off • Calculate VAAs • Canals on • Look at the other attributes • Catch my flight home

  16. Thanks: • Jeff Simley and USGS • Cindy McKay and Horizon Systems Inc. • NHD Community

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