Use of the NGS Web Site for Obtaining DFIRM Benchmarks

1. Use of the NGS Web Site for Obtaining DFIRM Benchmarks Arizona Floodplain Management Association Fall 2006 Meeting Dave Minkel Geodetic Advisor to Arizona, National Geodetic Survey Geospatial Professional, Arizona Professional Land Surveyors

2. Presentation Outline • NGS Published Benchmark data • How to get it • What is on the “data sheet” • How to get “local” benchmark data into NGS for publication • Submission procedure • Survey requirements

3. Where to get NGS Benchmark Data • NGS website - WWW.NGS.NOAA.GOV • Data Sheets • Our “standard” format for survey control • Simple text file (cut & paste from web browser) • Use NGS program DSWIN for PC-based searches (field work) • Shapefile sets • Does not contain descriptions

7. Where to get NGS Benchmark DataA “Local” Source Arizona Geoserver - sco.az.gov/website/geoserver/ • Good map interface, easy to navigate • Data Sheets come “live” from NGS data base • Station List not refreshed automatically, could be lacking new stations

10. NGS Data Sheet (Benchmark) – Things to look (out) for • Orthometric Height (commonly called elevation) • Do NOT use Ellipsoid (ELLIP) or Dynamic heights • Order/Class => 1st & 2nd Order, Class I & II • ADJUSTED orthometric height • VERTCON, use with caution and cite its use • Transformation from NGVD 29 to NAVD 88 • Accuracy dependent on locale • NOT acceptable for Height Modernization or subsidence surveys • POSTED, use with caution • Was not included in original NAVD88 adjustment, could have problems

11. NGS Data Sheet (Benchmark) – Things to look (out) for • 1-Decimeter Warning • GPS and Leveling do not agree • Subsidence • Geoid Model • Stability/Setting/GPS Code • Stability => A, B, C, or D • Setting Code – how’s the mark set • GPS Code – is it “GPSable” • Horizontal Position – Scaled or Adjusted • Scaled might not be real easy to find • Adjusted – pay dirt for a GPS Height Modernization Survey

12. The NGS Data Sheet A tour of some of the pertinent items on the sheet.

18. Subsidence Areas Cautionary Notes -

20. 1967 - 1980; Elevation Change DU01050 -2.302 ft DU01051 -2.282 ft 0.73 miles 2006 – Elevation Change (error) could be double, i.e. -4.604 ft & -4.564 ft, from published 1980 elevation (last year of leveling)

21. 1980-1992; Elevation Change B Stability -1.899 ft A Stability -1.891 ft Look for Bedrock Stations Setting Code = 66

22. To be explicit: NGS no longer performs leveling. NGS can assist with training and planning of leveling campaigns. In Arizona, most leveling is at least 14 years old (1992), but it can easily be much older.

23. How to get your existent benchmarks published by NGS – What You’ll Need to Do • Review/Investigate what survey data you have and the procedures used to establish the elevations • NGS Geodetic Advisor available for assistance • Contact NGS to request a review of the survey • NGS Geodetic Advisor can assist here too • “Bluebook” the survey(s) (i.e. put it in NGS format) • In-house assets • Contractual assets • Submit survey to NGS

24. How to get your existent benchmarks published by NGS – Requirements. • Policy Statement at: www.ngs.noaa.gov/INFO/incorp_data.shtml • General Requirements statement(s) • Data Submission Format a.k.a. “Bluebook” www.ngs.noaa.gov/FGCS/BlueBook/

26. How to get your existent benchmarks published by NGS – Requirements. • Policy Statement at: www.ngs.noaa.gov/INFO/incorp_data.shtml • General Requirements statement(s) • Data Submission Format a.k.a. “Bluebook” www.ngs.noaa.gov/FGCS/BlueBook/ • Requires (?) NGS software • Format / QC checking • Descriptions • Conversion to digital format • Monumentation - NOAA Manual NOS NGS l (1978) www.ngs.noaa.gov/PUBS_LIB/GeodeticBMs.pdf

27. How to get your existent benchmarks published by NGS – Requirements. • Accuracy - 2nd Order, Class II (minimum accepted) • Instrument - 0.50” repeatability • Rod • Single piece Invar (metal) • Manufacturer's Calibration data • Observations • 3-wire • Double Run (if > 25 km to network BMs) • Balanced set-ups (10 m maximum) • Time, Temp., Cloud Cover recorded

28. How to get your existent benchmarks published by NGS – Requirements. • Field Records • Not absolutely required, but you’ll need them to get all the data NGS requires for survey submission • NGS reserves the right to refuse a project if field records are not available

29. What do you do if you can’t submit your Benchmarks to NGS? • Re-run Levels to NGS specifications • Expensive, but most accurate • Do a GPS Height Modernization Survey • Fast, Efficient (saves $) • Accepted by FEMA, but not as accurate as leveling (cm rather than mm) • Yields a 3-D network • Support Arizona Height Modernization!! • Call Gene Trobia (AZ State Cartographer) • 602-542-3190

30. Arizona Height Modernization • FY06 - $428K allocated to Arizona • FY07 - Looking Grue$ome • The AZ Height Modernization “Plan” • Establish statewide CORS network • Establish a statewide 3-D network comparable to Maricopa County’s (every Township corner) • Analyze the vertical network and “repair” where needed • Establish the Arizona Spatial Reference Center • Data Distribution & Repository • Survey Processing & Bluebooking

31. Contact Information: Dave Minkel 1616 W. Adams St. Phoenix, AZ 85007 602-542-1569 (Office) 602-549-4744 (Mobile) dave.minkel@noaa.gov This presentation can be found at: ftp://ftp.ngs.noaa.gov/pub/Dminkel/AFMA_Presentation/