GEORECTIFIED 1982 AERIAL PHOTOGRAPHS OF THE UPPER TEXAS GULF OF MEXICO Metadata also available as Metadata: Identification_Information Data_Quality_Information Spatial_Data_Organization_Information Spatial_Reference_Information Entity_and_Attribute_Information Distribution_Information Metadata_Reference_Information Identification_Information: Citation: Citation_Information: Originator: University of Texas at Austin Bureau of Economic Geology (BEG) Publication_Date: January 2003 Title: GEORECTIFIED 1982 AERIAL PHOTOGRAPHS OF THE UPPER TEXAS GULF OF MEXICO Edition: first Geospatial_Data_Presentation_Form: remote-sensing image Online_Linkage: N/A Description: Abstract: This document describes a series of digital georectified images that were produced by the University of Texas at Austin Bureau of Economic Geology (Austin, TX). These georectified images provide coverage of the 1982 Texas Gulf of Mexico shoreline to approximately 5 km landward from Freeport to Sabine Pass. Galveston County, Texas funded the work as part of the U.S. Army Corps of Engineer's feasibility study activities for the Sabine Pass to Galveston Bay Shoreline Erosion Project. A georectified aerial photograph is a raster image of a vertical aerial photograph in which distortion has been removed and georeferencing information has been added. The images have a resolution of 800 ppi and are in false color infrared. They are projected in Universal Transverse Mercator (UTM) in meters on the North American Datum of 1983 (NAD83). The images were processed in ER Mapper format (.ers) and then converted to GeoTIFF. Purpose: The georectified images described in this document were created for the purpose of mapping shorelines and vegetation lines to be used in shoreline change analyses. Time_Period_of_Content: Time_Period_Information: Multiple_Dates/Times: Single_Date/Time: Calendar_Date: 19820610 Time_of_Day: unknown Single_Date/Time: Calendar_Date: 19820709 Time_of_Day: unknown Currentness_Reference: ground condition Status: Progress: Complete Maintenance_and_Update_Frequency: None planned Spatial_Domain: Bounding_Coordinates: West_Bounding_Coordinate: -95.355940 East_Bounding_Coordinate: -95.272085 North_Bounding_Coordinate: 28.988493 South_Bounding_Coordinate: 28.914669 Keywords: Theme: Theme_Keyword_Thesaurus: none Theme_Keyword: Georectified aerial photograph Theme_Keyword: rectified image Place: Place_Keyword: Texas Place_Keyword: Gulf Coast Place_Keyword: Galveston Place_Keyword: Texas Gulf Coast Place_Keyword: Gulf Of Mexico Temporal: Temporal_Keyword: 1982 Temporal_Keyword: 1980s Access_Constraints: none Use_Constraints: none Point_of_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: Jim Gibeaut Contact_Organization: University of Texas Bureau of Economic Geology Contact_Position: Research Associate Contact_Address: Address_Type: mailing address Address: University Station Box X City: Austin State_or_Province: TX Postal_Code: 78713-8924 Country: USA Contact_Voice_Telephone: (512) 471-0344 Contact_Electronic_Mail_Address: jim.gibeaut@beg.utexas.edu Browse_Graphic: Data_Set_Credit: Rachel Waldinger, Jim Gibeaut, Bureau of Economic Geology Native_Data_Set_Environment: Microsoft Windows NT Version 4.0 (Build 1381) Service Pack 6; ESRI ArcCatalog 8.1.0.642 Data_Quality_Information: Attribute_Accuracy: Completeness_Report: The imagery provides complete coverage of the upper Texas Gulf of Mexico shoreline plus approximately 5 km landward from Freeport to Sabine Pass. Positional_Accuracy: Horizontal_Positional_Accuracy: Horizontal_Positional_Accuracy_Report: Georectified aerial photographs are based on USGS Digital Orthophoto Quads (DOQs):The DOQ horizontal positional accuracy and the assurance of that accuracy depend, in part, on the accuracy of the data inputs to the rectification process. These inputs consist of the digital elevation model (DEM), aerotriangulation control and methods, the photo source camera calibration, scanner calibration, and aerial photographs that meet National Aerial Photography Program (NAPP) standards. The vertical accuracy of all DEMs are equivalent to or better than a Level 1 or 2 DEM, with a root mean square error (RMSE) of no greater than 7.0 meters. Field control is acquired by third order class 1 or better survey methods sufficiently spaced to meet National Map Accuracy Standards (NMAS) for 1:12,000-scale products. Aerial cameras have current certification from the USGS, National Mapping Division, Optical Science Laboratory. Test calibration scans are performed on all source photography scanners. Adjacent DOQs, when displayed together in a common planimetric coordinate system, may exhibit slight positional discrepancies across common DOQ boundaries. Linear features, such as streets, may not be continuous. These edge mismatches, however, still conform to positional horizontal accuracy within the NMAS. The Horizontal_Positional_Accuracy Value (see below) is an root mean square error (RMSE) of image positions to ground coordinates as determined by the orthorectification software used. (Source: Metadata for USGS DOQs, 1995) RMS error for Georectified images are less that 7 meters. Lineage: Source_Information: Source_Citation: Citation_Information: Originator: Texas General Land Office Title: false-color infrared 1982 aerial photograph prints Other_Citation_Details: The photography was flown at a scale of 1:24,000. The prints are 9"x9". Each image was scanned at 800 dpi on a flat-bed scanner by the BEG. Source_Scale_Denominator: 24,000 Type_of_Source_Media: aerial photograph print Source_Time_Period_of_Content: Time_Period_Information: Multiple_Dates/Times: Single_Date/Time: Calendar_Date: 6/28/1982 Time_of_Day: unknown Single_Date/Time: Calendar_Date: 9/5/1982 Time_of_Day: unknown Source_Currentness_Reference: ground condition Source_Contribution: Texas General Land Office Process_Step: Process_Description: Georectification of the aerial photographs involves the establishment of ground control points that link each image to its corresponding aerial coverage on a 1995 USGS digital orthophoto quarter quad (DOQQ). Points are chosen on the image that can be matched to points on the DOQQ. Road intersections and other cultural features are preferred as reference points rather than natural features. However, in many cases cultural features are lacking and features such as trees, shrubs, and the edges of water bodies are used. Where possible, points are evenly spaced across the image surface, with special emphasis on the edges of the image, and on areas near to the shoreline. The number of ground control points used for each image varies depending on how distorted the image is, and on the availability of suitable reference features. The average range is approximately 30 to 60 points per image. Once all the ground control points have been established, the image is rectified. Most images are rectified using a high-order polynomial algorithm, while some underwent a delaunay triangulation algorithm. Once the rectification was complete, the image was made semi-transparent and overlain on the DOQQ. In some areas a "double image" would occur, indicating that either more ground control points were needed, or that one or more existing ground control points had been placed incorrectly. In these cases, images were reprocessed to correct any remaining distortion. Process_Date: Nov., Dec 2002, Jan. 2003 Process_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: Rachel Waldinger Contact_Organization: Bureau of Economic Geology Contact_Position: Research Scientist Associate Contact_Address: Address_Type: mailing address Address: University station Box X City: Austin State_or_Province: TX Postal_Code: 78713 Country: USA Contact_Voice_Telephone: 9512) 472-5165 Contact_Electronic_Mail_Address: rachel.waldinger@mail.utexas.edu Spatial_Data_Organization_Information: Direct_Spatial_Reference_Method: Raster Raster_Object_Information: Raster_Object_Type: Pixel Row_Count: 10033 Column_Count: 10023 Vertical_Count: 1 Spatial_Reference_Information: Horizontal_Coordinate_System_Definition: Planar: Grid_Coordinate_System: Grid_Coordinate_System_Name: Universal Transverse Mercator Universal_Transverse_Mercator: UTM_Zone_Number: 15 Transverse_Mercator: Scale_Factor_at_Central_Meridian: 0.999600 Longitude_of_Central_Meridian: -93.000000 Latitude_of_Projection_Origin: 0.000000 False_Easting: 500000.000000 False_Northing: 0.000000 Planar_Coordinate_Information: Planar_Coordinate_Encoding_Method: row and column Coordinate_Representation: Abscissa_Resolution: 0.800245 Ordinate_Resolution: 0.800245 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 Entity_and_Attribute_Information: Detailed_Description: Entity_Type: Entity_Type_Label: Band_1 Attribute: Attribute_Label: ObjectID Attribute: Attribute_Label: Value Attribute: Attribute_Label: Red Attribute: Attribute_Label: Green Attribute: Attribute_Label: Blue Distribution_Information: Distributor: Contact_Information: Contact_Organization_Primary: Contact_Organization: University of Texas at Austin Bureau of Economic Geology Contact_Person: Jim Gibeaut Contact_Position: Research Associate Contact_Address: Address_Type: mailing address Address: University Station Box X City: Austin State_or_Province: TX Postal_Code: 78713 Country: USA Contact_Voice_Telephone: (512) 471-0344 Standard_Order_Process: Digital_Form: Digital_Transfer_Information: Format_Name: TIFF Transfer_Size: 95.908 Available_Time_Period: Time_Period_Information: Multiple_Dates/Times: Single_Date/Time: Calendar_Date: 6/10/82 Time_of_Day: unknown Single_Date/Time: Calendar_Date: 7/9/82 Time_of_Day: unknown Metadata_Reference_Information: Metadata_Date: 20030129 Metadata_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: Rachel Waldinger Contact_Organization: University of Texas Bureau of Economic Geology Contact_Position: Research Scientist Associate Contact_Address: Address_Type: mailing address Address: University Station Box X City: Austin State_or_Province: TX Postal_Code: 78713 Country: USA Contact_Voice_Telephone: (512) 475-9551 Contact_Electronic_Mail_Address: rachel.waldinger@mail.utexas.edu Metadata_Standard_Name: FGDC Content Standards for Digital Geospatial Metadata Metadata_Standard_Version: FGDC-STD-001-1998 Metadata_Time_Convention: local time Metadata_Extensions: Online_Linkage: Profile_Name: ESRI Metadata Profile Metadata_Extensions: Online_Linkage: Profile_Name: ESRI Metadata Profile Generated by mp version 2.7.3 on Wed Jan 29 10:56:41 2003