DIGITAL FLOOD INSURANCE RATE MAP DATABASE, Scotland County, North Carolina

Resource lineage description

source

source description  Source Contribution: Location of roads, railroads, bridges, streams, and other physical features.Source Type CD-ROM

representative resolution scale:

Scale denominator: 2400

source citation

Title Digital Orthophotos, Scotland COunty, NC

publication  Date   2008-10-07

presentationForm  REMOTE SENSING IMAGE

other Citation Details  Digital orthoimagery was provided by the North Carolina Floodplain Mapping Program. The imagery was flown in March 2008 at 6-inch pixel resolution for use at a scale of 1:2400.

cited responsible party - publisher

organisation Name  North Carolina Floodplain Mapping Program

Contact information

Address

, Raleigh, NC

cited responsible party - originator

organisation Name  North Carolina Floodplain Mapping Program

source

source description  Source Contribution: Spatial and attribute information for cross sections, floodplain information, BFEs, general structures, and station start descriptions.Source Type CD-ROM

representative resolution scale:

Scale denominator: 12000

source citation

Title Flood Insurance Study, Scotland County, North Carolina.

publication  Date   2010-09-22

presentationForm  mapDigital

other Citation Details  This Flood Insurance Study was produced through a cooperative partnership between the State of North Carolina and FEMA. The North Carolina Floodplain Mapping Program, through FEMA's Cooperating Technical State (CTS) Initiative, is conducting flood hazard analyses and producing updated, digital FIRM panels for all North Carolina communities. A more detailed description of the areas studied and the engineering methods used can be found in sections 4.0 and 5.0 of the accompanying Flood Insurance Study report. Additional information regarding the North Carolina Floodplain Mapping Program and the data collected during the mapping process are available at http://www.ncfloodmaps.com.

cited responsible party - publisher

organisation Name  North Carolina Floodplain Mapping Program

Contact information

Address

, Raleigh, NC

cited responsible party - originator

organisation Name  North Carolina Floodplain Mapping Program

source

source description  Source Contribution: Grid of DFIRM panels.Source Type CD-ROM

representative resolution scale:

Scale denominator: 12000

source citation

Title Scotland County, North Carolina, Digital Flood Insurance Rate Map

publication  Date   2010-09-22

presentationForm  mapDigital

other Citation Details  Grid of FIRM panels created for this Flood Insurance Study.

cited responsible party - publisher

organisation Name  North Carolina Floodplain Mapping Program

Contact information

Address

, Raleigh, NC

cited responsible party - originator

organisation Name  North Carolina Floodplain Mapping Program

source

source description  Source Contribution: National Geodetic Survey reference points (bench marks).Source Type CD-ROM

representative resolution scale:

Scale denominator: 24000

source citation

Title Geodetic bench marks

publication  Date   2010-01-01

presentationForm  mapDigital

other Citation Details  The National Geodetic Survey (NGS) serves as the Nation's depository for geodetic data in the National Spatial Reference System. These geodetic data include bench marks and other control points that provide the base of reference for latitude, longitude, height, scale, orientation, and gravity measurements used throughout the United States.

cited responsible party - publisher

organisation Name  National Geodetic Survey

Contact information

Address

, Silver Spring, MD

cited responsible party - originator

organisation Name  National Geodetic Survey

source

source description  Source Contribution: North Carolina Geodetic Survey reference points (bench marks).Source Type CD-ROM

representative resolution scale:

Scale denominator: 24000

source citation

Title Geodetic bench marks

publication  Date   2010-01-01

presentationForm  mapDigital

other Citation Details  The North Carolina Geodetic Survey (NCGS) is the lead agency in North Carolina responsible for the coordination of geodetic activities among State agencies. NCGS coordinates the development, adoption, and promotion of: (a) classification standards of content, format, and accuracy for geodetic data and (b) standards and specifications for geodetic surveying techniques and technologies for use by all State agencies and, encourages their use by non-state agencies. NCGS disseminates information on technological improvements for collecting geodetic data and coordinates the plans and requirements for geodetic activities of State agencies. The NCGS Geodetic Survey Section establishes precisely located monuments on the North Carolina Grid System and Bench Marks referenced to a vertical datum (NGVD 1929 and NAVD 1988). The Geodetic Survey Section establishes and maintains the official survey base of the state of North Carolina to support mapping, boundary determination, property delineation, infrastructure development, resource evaluation surveys, and scientific applications.

cited responsible party - publisher

organisation Name  North Carolina Geodetic Survey

Contact information

Address

, Raleigh, NC

cited responsible party - originator

organisation Name  North Carolina Geodetic Survey

source

source description  Source Contribution: Spatial and attribute information for political entities (counties, municipalities) and military and Native American lands.Source Type CD-ROM

representative resolution scale:

Scale denominator: 24000

source citation

Title Political boundaries

publication  Date   2010-09-22

presentationForm  mapDigital

other Citation Details  Political boundaries shown on the DFIRM were derived from multiple sources including N.C. Department of Transporation, the N.C. Geographic Database, and Scotland County.

cited responsible party - publisher

organisation Name  North Carolina Floodplain Mapping Program

Contact information

Address

, Raleigh, NC

cited responsible party - originator

organisation Name  North Carolina Center for Geographic Information and Analysis

source

source description  Source Contribution: Spatial and attribute information for transportation features including roads, railroads, and airports.Source Type CD-ROM

representative resolution scale:

Scale denominator: 24000

source citation

Title Transportation features

publication  Date   2010-09-22

presentationForm  mapDigital

other Citation Details  Transportation features were derived from multiple sources including N.C. Department of Transporation, the N.C. Geographic Database, and Scotland County.

cited responsible party - publisher

organisation Name  North Carolina Floodplain Mapping Program

Contact information

Address

, Raleigh, NC

cited responsible party - originator

organisation Name  North Carolina Center for Geographic Information and Analysis

source

source description  Source Contribution: Base map surface water features.Source Type CD-ROM

representative resolution scale:

Scale denominator: 12000

source citation

Title Scotland County, North Carolina, Digital Flood Insurance Rate Map

publication  Date   2010-09-22

presentationForm  mapDigital

other Citation Details  Base map surface water features digitized from Digital Orthophoto Quadrangles.

cited responsible party - publisher

organisation Name  North Carolina Floodplain Mapping Program

Contact information

Address

, Raleigh, NC

cited responsible party - originator

organisation Name  North Carolina Floodplain Mapping Program

source

source description  Source Contribution: Grid of USGS 7.5-Minute Series Topographic Maps.Source Type CD-ROM

representative resolution scale:

Scale denominator: 24000

source citation

Title 7.5-Minute Quadrangle Grid

publication  Date   1999-01-01

presentationForm  mapDigital

other Citation Details  Grid of USGS 7.5-Minute Series Topographic Maps.

cited responsible party - publisher

organisation Name  ESRI

Contact information

Address

, Redlands, CA

cited responsible party - originator

organisation Name  U.S. Geological Survey

AbsoluteExternalPositionalAccuracy

name Of Measure Horizontal Positional Accuracy Report

evaluation Method Description  The DFIRM Database consists of countywide vector files and associated attributes produced in conjunction with the hardcopy FEMA FIRM. The published effective FIRM and DFIRM are issued as the official designation of the SFHAs. As such they are adopted by local communities and form the basis for administration of the NFIP. For these purposes they are authoritative. Provisions exist in the regulations for public review, appeals and corrections of the flood risk information shown to better match real world conditions. As with any engineering analysis of this type, variation from the estimated flood heights and floodplain boundaries is possible. Details of FEMA's requirements for the FISs and flood mapping process that produces these data are available in the Guidelines and Specifications for Flood Hazard Mapping Partners. For streams restudied by detailed and limited detail methods, the 1% and 0.2% annual chance floodplains were delineated using flood elevations determined at each cross section. Between cross sections, the boundaries were interpolated using topographic data acquired using airborne LIDAR. This LIDAR data was acquired during the winter 2001 flying season. The topographic data satisfies a vertical root-mean- square error (RMSE) accuracy standard of 20cm (1.3 feet accuracy at the 95% confidence limit) for coastal areas and 25 cm (1.6 feet accuracy at the 95% confidence limit) for non-coastal areas of the State. These data could be contoured at roughly a 2- foot vertical contour interval. All elevations were referenced to the NAVD 88 and reflect orthometric heights. Variably spaced, bare-earth digital topographic data in ASCII point file format were combined with imagery (either flown concurrently with the LIDAR data or using existing digital orthophotos) to establish a Triangulated Irregular Network (TIN) of digital elevation points, which include selected breaklines to be used for hydraulic modeling. Furthermore, a uniformly spaced sampling of the TIN resulted in uniformly spaced Digital Elevation Models (DEMs), with 20 ft x 20 ft post spacing, which was generated in multiple file formats. For coastal floodplains, after analyzing wave heights along each transect, wave elevations were interpolated between transects. Various source data were used in the interpolation, including topographic data described above. Horizontal accuracy was tested by manual comparison of source graphics with hardcopy plots and a symbolized display on an interactive computer graphic system. Independent quality control testing of FEMA's DFIRM database was also performed.

AbsoluteExternalPositionalAccuracy

name Of Measure Vertical Positional Accuracy Report

evaluation Method Description  The DFIRM Database consists of countywide vector files and associated attributes produced in conjunction with the hard copy FEMA FIRM. The published effective FIRM and DFIRM maps are issued as the official designation of the SFHAs. As such they are adopted by local communities and form the basis for administration of the NFIP. For these purposes they are authoritative. Provisions exist in the regulations for public review, appeals and corrections of the flood risk information shown to better match real world conditions. As with any engineering analysis of this type, variation from the estimated flood heights and floodplain boundaries is possible. Details of FEMA's requirements for the FISs and flood mapping process that produces these data are available in the Guidelines and Specifications for Flood Hazard Mapping Partners. For streams restudied by detailed and limited detail methods, the 1% and 0.2% annual chance floodplains were delineated using flood elevations determined at each cross section. Between cross sections, the boundaries were interpolated using topographic data acquired using airborne LIDAR. This LIDAR data was acquired during the winter 2001 flying season. The topographic data satisfies a vertical root-mean- square error (RMSE) accuracy standard of 20cm (1.3 feet accuracy at the 95% confidence limit) for coastal areas and 25 cm (1.6 feet accuracy at the 95% confidence limit) for non-coastal areas of the State. These data could be contoured at roughly a 2- foot vertical contour interval. All elevations were referenced to the NAVD 88 and reflect orthometric heights. Variably spaced, bare-earth digital topographic data in ASCII point file format were combined with imagery (either flown concurrently with the LIDAR data or using existing digital orthophotos) to establish a Triangulated Irregular Network (TIN) of digital elevation points, which include selected breaklines to be used for hydraulic modeling. Furthermore, a uniformly spaced sampling of the TIN resulted in uniformly spaced Digital Elevation Models (DEMs), with 20 ft x 20 ft post spacing, which was generated in multiple file formats. For coastal floodplains, after analyzing wave heights along each transect, wave elevations were interpolated between transects. Various source data were used in the interpolation, including topographic data described above.

Completeness Commission

evaluation Method Description  Data contained in the DFIRM Database files reflect the content of the source materials. Features may have been eliminated or generalized on the source graphic, due to scale and legibility constraints. With new mapping, FEMA plans to maintain full detail in the spatial data it produces. However, older information is often transferred from existing maps where some generalization has taken place. Flood risk data are developed for communities participating in the NFIP for use in insurance rating and for floodplain management. Flood hazard areas are determined using statistical analyses of records of river flow, storm tides, and rainfall; information obtained through consultation with the communities; floodplain topographic surveys; and hydrological and hydraulic analysis. Both detailed and approximate analyses are employed. Generally, detailed analyses are used to generate flood risk data only for developed or developing areas of communities. For areas where little or no development is expected to occur, FEMA uses approximate analyses to generate flood risk data. Typically, only drainage areas that are greater than one square mile are studied.

Completeness Omission

evaluation Method Description  Data contained in the DFIRM Database files reflect the content of the source materials. Features may have been eliminated or generalized on the source graphic, due to scale and legibility constraints. With new mapping, FEMA plans to maintain full detail in the spatial data it produces. However, older information is often transferred from existing maps where some generalization has taken place. Flood risk data are developed for communities participating in the NFIP for use in insurance rating and for floodplain management. Flood hazard areas are determined using statistical analyses of records of river flow, storm tides, and rainfall; information obtained through consultation with the communities; floodplain topographic surveys; and hydrological and hydraulic analysis. Both detailed and approximate analyses are employed. Generally, detailed analyses are used to generate flood risk data only for developed or developing areas of communities. For areas where little or no development is expected to occur, FEMA uses approximate analyses to generate flood risk data. Typically, only drainage areas that are greater than one square mile are studied.

ConceptualConsistency

measure Description  When FEMA revises an FIS, adjacent studies are checked to ensure agreement between flood elevations at the boundaries. Likewise flood elevations at the confluence of streams studied independently are checked to ensure agreement at the confluence. The FIRM and the FIS are developed together and care is taken to ensure that the elevations and other features shown on the flood profiles in the FIS agree with the information shown on the FIRM. However, the elevations as shown on the FIRM are rounded whole-foot elevations. They must be shown so that a profile recreated from the elevations on the FIRM will match the FIS profiles within one half of one foot.