Identification_Information: Citation: Citation_Information: Originator: Canaan Valley Institute Publication_Date: July 2004 Title: ESRI-format LiDAR DEM and Hillshade Grids Geospatial_Data_Presentation_Form: vector digital data Online_Linkage: \\bigsandy\X\projects\gilmer_little_kanawha\lidar\reference\rawdata_tiles.shp Description: Abstract: 1-meter DEM (with values in meters) and Hillshade grids of the LiDAR data collected by Airborne 1. These grids were calculated from the LiDAR Mass Points coverages. A DEM and Hillshade grid exist for each 1/16 quad tile. These rectangular tiles are equivalent in size to 1/16 of a USGS 7.5' quadrangle. The grid data maintains a 100-meter buffer beyond the rectangluar tile boundary to enable seamless mosaicking and merging with adjacent tiles. Some grids do not constitute a full 1/16 tile due to the irregular nature of the data acquisition boundary. Purpose: DEM and Hillshade data may be used for surface analysis or display. The data represents a bare earth condition which lends itself to hydrologic investigations. The grids fully cover the Gilmer County, WV LiDAR acquisition area. This project is being conducted as part of a FEMA Cooperative Technical Partners grant for floodplain mapping initiatives.. The project is focused on Gilmer County and the Little Kanwaha subbasin below Burnsville Dam. Supplemental_Information: 272 ArcINFO grids exist with the naming convention: DEM_tileid 272 ArcINFO grids exist with the naming convention: HLSHD_tileid Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: March 25, 2004 Ending_Date: April 7, 2004 Currentness_Reference: ground condition Status: Progress: Complete Maintenance_and_Update_Frequency: None planned Spatial_Domain: Bounding_Coordinates: West_Bounding_Coordinate: -81.130334 East_Bounding_Coordinate: -80.493656 North_Bounding_Coordinate: 39.169633 South_Bounding_Coordinate: 38.618851 Keywords: Theme: Theme_Keyword_Thesaurus: None Theme_Keyword: LiDAR Theme_Keyword: Elevation Theme_Keyword: Floodplain Place: Place_Keyword: Gilmer County Place_Keyword: Little Kanawha River Place_Keyword: West Virginia Access_Constraints: None Use_Constraints: None Point_of_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: Canaan Valley Institute Contact_Address: Address_Type: mailing address Address: Box 673 City: Davis State_or_Province: WV Postal_Code: 26260 Country: USA Contact_Voice_Telephone: 304 463-4739 Native_Data_Set_Environment: Microsoft Windows 2000 Version 5.1 (Build 2600) Service Pack 1; ESRI ArcCatalog 8.3.0.800 Data_Quality_Information: Attribute_Accuracy: Logical_Consistency_Report: DEM and Hillshade grids reflect the distribution of Mass Points. Gaps in the point data will manifest themselves in the gridded data as large angular areas of a uniform value. The angular areas are a remnant of an intermeadiate step between point and grid which involves the generation of an TIN surface. The angular areas represent places where large triangular faces were interpolated due to a lack of point data. Likewise, some areas have a much denser representation of points and may manifest themselves as areas with excessive noise in these derivative products. It should be noted that the DEM and Hillshade grids, like the Mass Points, may not constitute full edge-to-edge tile coverage due to the nature of the irregular data acquisition boundary. Completeness_Report: Complete Positional_Accuracy: Horizontal_Positional_Accuracy: Horizontal_Positional_Accuracy_Report: QA/QC of the raw LiDAR data by Airborne 1 demonstrated that 95% of the LiDAR points fall within +/- 0.20m when checked against the control provided by Airborne1 Corporation. Comparison of the Mass Points coverage with the raw data coordinates did demonstrate a coordinate shift. This shift is most noticable in the Y-coordinate and may be as large as 0.25 meters (less than 1 foot). The maximum shift in the X-coordinate is less than 2 centimeters. The coordinate shift is not uniform among the point features. The average shift for Y-coordinates is 0.125 meters and 0.007811 for the X-coordinate. This horizontal shift is a result of the precision applied to the point coverage during the GENERATE process in ArcINFO. The Mass Points were created with a single precision which has the effect of shortening the coordinate string and causes rounding. The precision setting has no effect on the Z or I measurement values. This shift does not significantly affect the horizontal accuracy of DEM or Hillshade grids. These grids are created from a TIN surface at a resolution of 1-meter. The shift even at maximum is less than 1/2-meter and so a representation of the surface as a 1-meter pixel exceeds the difference caused by the coordinate shift. Vertical_Positional_Accuracy: Vertical_Positional_Accuracy_Report: QA/QC of the raw LiDAR data by Airborne 1 demonstrated that 95% of the LiDAR points fall within +/- 0.20m when checked against the control provided by Airborne1 Corporation. The DEM product, when compared to the Mass Points coverage, demonstrates that 81% of the values (Z) have a difference of less than +/- 0.20m. 97% of the tested points have a difference less than +/-0.36m. Quantitative_Vertical_Positional_Accuracy_Assessment: Vertical_Positional_Accuracy_Value: Z Lineage: Source_Information: Source_Citation: Citation_Information: Originator: Airborne 1 Publication_Date: April 2004 Title: Raw LiDAR Data (bare earth) Geospatial_Data_Presentation_Form: tabular digital data Source_Scale_Denominator: Unknown Type_of_Source_Media: DVD-ROM Source_Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: April 2004 Source_Currentness_Reference: ground condition Source_Citation_Abbreviation: Airborne 1 Bare Earth (.lst) Text Files Source_Contribution: Text files containing values X, Y, Z, and I for each point Process_Step: Process_Description: Canaan Valley Institute processed the Airborne 1 Bare Earth (.lst) Text Files using ArcINFO AML to create a suite of ESRI-format data products. The DEM and Hillshade grids were created through this method which involved the combination of individual text files for each 1/16 quad tile area. These text files were uploaded into an ArcINFO table which was then converted to a point coverage and joined back to the original ArcINFO table so as to retain the essential Z and I attributes. A TIN was created from the point coverage. Which, in turn, was used to interpolate a DEM surface. The DEM is a floating point grid with values in meters representing the surface elevation. The resulting DEM was then used to create a Hillshade grid. The Hillshade is an integer point grid whose values represent shadow and shading. The Hillshade was produced using default azimuth and altitude settings in ArcINFO. The DEM and Hillshade grids were then clipped to the extent of the 1/16 tile areas with a 100-meter buffer. Process_Date: July 2004 Spatial_Data_Organization_Information: Direct_Spatial_Reference_Method: Vector Point_and_Vector_Object_Information: SDTS_Terms_Description: SDTS_Point_and_Vector_Object_Type: G-polygon Point_and_Vector_Object_Count: 2178 Spatial_Reference_Information: Horizontal_Coordinate_System_Definition: Planar: Grid_Coordinate_System: Grid_Coordinate_System_Name: Universal Transverse Mercator Universal_Transverse_Mercator: UTM_Zone_Number: 17 Transverse_Mercator: Scale_Factor_at_Central_Meridian: 0.999600 Longitude_of_Central_Meridian: -81.000000 Latitude_of_Projection_Origin: 0.000000 False_Easting: 500000.000000 False_Northing: 0.000000 Planar_Coordinate_Information: Planar_Coordinate_Encoding_Method: coordinate pair Coordinate_Representation: Abscissa_Resolution: 0.000128 Ordinate_Resolution: 0.000128 Planar_Distance_Units: meters Geodetic_Model: Horizontal_Datum_Name: North American Datum of 1983 Ellipsoid_Name: Geodetic Reference System 80 Semi-major_Axis: 6378137.000000 Denominator_of_Flattening_Ratio: 298.257222 Vertical_Coordinate_System_Definition: Altitude_System_Definition: Altitude_Datum_Name: North American Vertical Datum of 1988 Altitude_Resolution: 0.01 Altitude_Distance_Units: meters Altitude_Encoding_Method: Attribute values Entity_and_Attribute_Information: Detailed_Description: Entity_Type: Entity_Type_Label: rawdata_tiles Attribute: Attribute_Label: FID Attribute_Definition: Internal feature number. Attribute_Definition_Source: ESRI Attribute_Domain_Values: Unrepresentable_Domain: Sequential unique whole numbers that are automatically generated. Attribute: Attribute_Label: Shape Attribute_Definition: Feature geometry. Attribute_Definition_Source: ESRI Attribute_Domain_Values: Unrepresentable_Domain: Coordinates defining the features. Attribute: Attribute_Label: POLYID Attribute: Distribution_Information: Distributor: Contact_Information: Contact_Organization_Primary: Contact_Organization: Canaan Valley Institute Contact_Address: Address_Type: mailing address Address: Box 673 City: Davis State_or_Province: WV Postal_Code: 26260 Contact_Voice_Telephone: 304 463-4739 Resource_Description: ESRI-format GIS data Distribution_Liability: CVI makes no warranty, express or implied, of any nature or effect as to the data and related graphics contained herein. CVI shall not be held liable for improper or incorrect use of the data and graphics contained herein by a buyer, donee or other person relying upon the same. It is the responsibility of the person using or relying upon these data and graphics to do so appropriately and consistently within the limitations of geospatial data in general and these data in particular. Each user of these data and graphics are instructed to give careful attention to the contents of all metadata documentation associated with these data. CVI will not be liable for any direct, indirect, special, general, incidental or consequential damages arising out of the use or inability to use the data, related graphics, or any accompanying documentation. Standard_Order_Process: Digital_Form: Digital_Transfer_Information: Transfer_Size: 0.007 Metadata_Reference_Information: Metadata_Date: 20040824 Metadata_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: Canaan Valley Institute Contact_Position: Geospatial Coordinator Contact_Address: Address_Type: mailing address Address: P.O. Box 673 City: Davis State_or_Province: WV Postal_Code: 26260 Country: USA Contact_Address: Address_Type: physical address Address: 2nd Floor, B&L Building Address: Front Street Circle Address: Douglas Road City: Thomas State_or_Province: WV Postal_Code: 26292 Country: USA Contact_Voice_Telephone: 304-463-4739 Contact_Voice_Telephone: 800-922-3601 Contact_Facsimile_Telephone: 304-463-4759 Hours_of_Service: M-F 9-5 Contact_Instructions: Please ask for the Geospatial Coordinator when calling. 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