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Streambed Mapping Project For Western North Carolina Counties

Streambed Mapping Project For Western North Carolina Counties. Presentation Topics. Background Task Descriptions Progress To Date Path Forward. Background. Background. PROJECT TEAM Sponsor: North Carolina Center for Geographic Information and Analysis

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Streambed Mapping Project For Western North Carolina Counties

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  1. Streambed Mapping Project For Western North Carolina Counties

  2. Presentation Topics • Background • Task Descriptions • Progress To Date • Path Forward

  3. Background

  4. Background • PROJECT TEAM • Sponsor: North Carolina Center for Geographic Information and Analysis • Advisory Committee: USGS, EPA, NC DWQ, NC DOT, NC EEP, City of Charlotte, Buncombe County • Contractors: Watershed Concepts, EarthData, ESP Associates, Data Enhancement Services

  5. Background • North Carolina Senate Bill 1152 • Mandated that a plan be created to improve the mapping of streams in the State of North Carolina • Creation of new dataset to map surface waters in North Carolina including streams, lakes, ponds, and other water bodies

  6. Background

  7. Background

  8. Background • Stream Mapping Working Group • Four meetings in late 2004 • Requirements Survey / User Requirements Summary • Stream Mapping Implementation Plan • Submitted to the NC Legislature in January 2005 • Endorsed by the GICC and presented to the General Assembly’s Environmental Review Commission in January of 2005 • Statewide implementation in a 5 year period Website for Document Download: http://cgia.cgia.state.nc.us/streammap

  9. Background • A benefit / cost analysis was performed to show the value of the Streambed Mapping Project to agencies as well as the general public. Note: This estimate yields an initial B/C ratio of 16:1, a value that does not reflect long term benefits.

  10. Background • Senate Bill 7 Hurricane Recovery Act • Allocated mapping funds for the 19 counties in Western North Carolina that were declared disaster areas after Hurricanes Frances and Ivan.

  11. Task Descriptions

  12. Task Descriptions • The Streambed Mapping Project is comprised of many tasks including: • Project Management • Horizontal Accuracy Study • Schema and Geodatabase Design • Software Tool Creation • Drawing of Streamlines and Water Bodies to 6-Acre Upstream Drainage Limit • NHD Conflation and Attribution of Streamlines and Water Bodies

  13. Project Management • Project Management Plan • Project Organization, Communications, QA/ QC, Change Management, Risk Management, File Management, Project Schedule and Deliverables • Coordination Activities • Advisory Committee formed to assist with project decisions

  14. Horizontal Accuracy Study • Purpose was to perform a pilot study to determine the horizontal accuracy of the streamlines in various situations. • Study was based on: • 250 Survey Points, 100 miles of stream • Varying degrees of terrain density, differing imagery resolutions, and varying drainage areas • Varying land characteristics (open, brush, forest, and urban)

  15. Horizontal Accuracy Study • Two GIS specialists digitized the streamlines • Two types of imagery (DOQQs and Local) • TIN surfaces generated from bare earth LIDAR returns, hillshades, DEMs, and contours • Each analysts work performed independently of one another • Simultaneously, surveyors collected 250 GPS points and stream widths using survey grade GPS and OPUS post-processing methods • ArcHydro, LIDAR Tool, 1:24K NHD streams, NCFMP Breaklines, Independently-Derived Streamlines, and Streamlines Derived to the 6-Acre Drainage Area Limit were also analyzed against the survey points and the analysts linework

  16. Horizontal Accuracy Study

  17. Horizontal Accuracy Study Average Distance from Stream Bank for 100% of the Data Note: Analyst 1, Analyst 2, and Independently-Derived Streamlines are over twice the accuracy of the existing NHD streamlines

  18. Horizontal Accuracy Study • Cumulative Probability Distribution for Selected Manual Methods (Including Analysts 1 and 2, NC Independently Derived Streamlines and 1:24K NHD) for All Streams

  19. Horizontal Accuracy Study Observed Accuracy by Land Cover Setting

  20. Horizontal Accuracy Study Findings: • Six different methods tested • In general, manual processes more accurate than automated processes • Manual methods 2 and 3 times more accurate than existing 1:24K NHD • NHD for all points -- 70% were within 15 ft of stream banks, 85% are within 25 ft of stream banks, and 90% were within 35 ft of stream banks • Manual process for all points -- 70% within 3 ft of stream banks, 85% within 10 ft of stream banks, and 90% within 15 ft of stream banks • Of open, brush, forest, and urban, the urban environment posed the biggest challenge in terms of horizontal placement

  21. Geodatabase Schema and Design • Schema • Various models reviewed • NHD data model appended with additional attributes previously identified in the Implementation Plan • Design • Conceptual – feature classes, object classes, entity relationships, cardinality, topologies, and domains defined • Logical – finalizes the conceptual design • Physical – utilizes SQL Server 2000 with SDE

  22. Geodatabase Schema and Design • Additional Features Include State Custom Tables • Change Table: Tracks history of edits • Submetadata Table: Provides information on source data used to create or edit stream data • Significant Coordination Effort • Data Dictionary Created

  23. Geodatabase Schema and Design

  24. Software Tool Development • Suite of Software Tools • Suite of software tools created to assist with horizontal alignment, attribution and conflation of the 1:24K NHD attributes to the dataset • Optimize both production and quality of the Streambed Mapping Dataset • Tools incorporated into the “Streambed Mapping Analyst Toolset” as an extension in ArcGIS, and will be made available to the public • Design • User requirements collection • Prototype Screenshots • Coding • Testing • Software Requirements Document • User Guide and Online Help

  25. Software Tool Development • Project Configuration Options Tool • Multiple Dataframe Modeler • Create Feature Types Toolset • Source File Comparison Tool • Streambed Mapping Analyst Toolset – Horizontal Alignment Tools • Horizontal Placement QC Tool • Flow Checker Tool • Tree Builder Tool • NHD Breakpoint Extraction Tool • Move Breakpoint Tool

  26. Software Tool Development • Assign Streambed Mapping Attributes Tool • Drainage Area Transfer and QC Tool • NHD Batch Attribute Transfer Tool • NHD Manual Attribute Transfer Toolset • QC Streambed Mapping Attributes Tool • Populate Submetadata Table Tool • NHD Cross Reference and Change Table Population Tool • Stream Leveling and Flow Table Population Tools • Streambed Mapping Analyst Toolset – Attribution / Conflation Tools

  27. Streamline and Waterbody Identification and Attribution • Horizontal Alignment • Streamlines terminate at the 6-acre drainage area upstream limit – creates a consistent dataset • Same base data used for alignment as the sources used for the Horizontal Accuracy Study • Increasing both the quality and quantity of streams in existing stream files

  28. Streamline and Waterbody Identification and Attribution

  29. Streamline and Waterbody Identification and Attribution

  30. Streamline and Waterbody Identification and Attribution

  31. Streamline and Waterbody Identification and Attribution

  32. Streamline and Waterbody Identification and Attribution • Attribution • All attributes found in the 1:24K NHD are conflated to the Streambed Mapping Dataset (point, line, polygon) • Additional attributes placed in an appended table to the NHD model • Reach codes conflated from 1:24K NHD data, and generated for new streams that do not exist in the NHD • All changes from existing 1:24K NHD attributes are recorded in the Reach Cross Reference Table and the Change Table created for the project • Attribution performed with the assistance of automated tools

  33. Progress To Date

  34. Progress To Date • Project Management Plan created • Multiple stakeholder briefings and updates • Accuracy Study completed – final report of findings submitted • Geodatabase finalized and physical Geodatabase installed • Prototypes created for all tools; tools finalized & implemented • User guide and online help completed for all tools • Software Requirements Specification Document finalized

  35. Progress To Date • First Delivery Area Submitted as Final to State (Pigeon) • Two Additional Delivery Areas (Upper New and Upper Yadkin, Seneca) have been finalized as of beginning of year

  36. Path Forward

  37. Path Forward • Entire project is a 2 year effort with a completion date of Summer 2007 for all 19 counties • A long term maintenance plan for the Streambed Mapping Dataset will be developed that documents the business and technical requirements of project stakeholders • North Carolina will develop an NHD Stewardship Agreement with USGS for long term maintenance of NC Stream Mapping dataset

  38. Discussion / Questions

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