USGS High Resolution Orthoimage, Raleigh-Durham, NC

Metadata:

• Identification_Information
• Data_Quality_Information
• Spatial_Reference_Information
• Metadata_Reference_Information

Identification_Information:

Citation:

Citation_Information:

Originator: U.S. Geological Survey

Publication_Date: 2003

Title: USGS High Resolution Orthoimage, Raleigh-Durham, NC

Geospatial_Data_Presentation_Form: remote sensing image

Publication_Information:

Publication_Place: Sioux Falls, SD

Publisher: U.S. Geological Survey

Description:

Abstract:

An orthoimage is remotely sensed image data in which displacement of features in the image caused by terrain relief and sensor orientation have been mathematically removed. Orthoimagery combines the image characteristics of a photograph with the geometric qualities of a map. For this dataset, the natural color orthoimages were produced at 0.3-meter pixel resolution (approximately 1-foot). The design accuracy is estimated not to exceed 3-meter diagonal RMSE (2.12m RMSE in X or Y). Each orthoimage provides imagery for a 1500- by 1500-meter block on the ground. The projected coordinate system is UTM with a NAD83 datum. There is no image overlap between adjacent files. The naming convention is based on the U.S. National Grid (USNG), taking the coordinates of the SW corner of the orthoimage.

Purpose:

This data has been created as a result of the need for having geospatial data immediately available and easily accessible in order to enhance the capability of Federal, State, and local emergency responders, as well as plan for homeland security efforts.

Supplemental_Information:

Spatial-specific information not available

Time_Period_of_Content:

Time_Period_Information:

Single_Date/Time:

Calendar_Date: 20020328

Currentness_Reference: ground condition

Status:

Progress: complete

Maintenance_and_Update_Frequency: irregular

Spatial_Domain:

Bounding_Coordinates:

West_Bounding_Coordinate:-78.68276076

East_Bounding_Coordinate:-78.67501891

North_Bounding_Coordinate:35.74018359

South_Bounding_Coordinate:35.7303267

Keywords:

Theme:

Theme_Keyword_Thesaurus: none

Theme_Keyword: 0.3 meter orthoimage

Theme_Keyword: rectified photograph

Theme_Keyword: rectified image

Theme_Keyword: orthophoto

Theme_Keyword: natural color orthophoto

Theme_Keyword: orthoimage

Theme_Keyword: image map

Place:

Place_Keyword_Thesaurus:

U.S. Department of Commerce, 1995, Countries, Dependencies, Areas of Special Sovereignty, and Their Principal Administrative Divisions (Federal Information Processing Standard (FIPS) 10-4): Washington, D.C., National Institute of Standards and Technology.

Place_Keyword: US

Place:

Place_Keyword_Thesaurus:

U.S. Department of Commerce, 1987, Codes for the Identification of the States, the District of Columbia and the outlying areas of the United States, and associated areas (Federal Information Processing Standard (FIPS) 5-2): Washington, D.C., National Institute of Standards and Technology.

Place_Keyword: NC

Place:

Place_Keyword_Thesaurus: None

Place_Keyword: Raleigh-Durham, NC

Access_Constraints: none

Use_Constraints:

None. However, users should be aware that temporal changes may have occurred since this data set was collected and that some parts of this data may no longer represent actual surface conditions. Users should not use this data for critical applications without a full awareness of it's limitations. Acknowledgment of the U.S. Geological Survey would be appreciated for products derived from these data.

Data_Set_Credit:

The Lidar data used in the Orthorectification process for this imagery was developed for the Floodplain Mapping Program, North Carolina Division of Emergency Management and obtained in cooperation wtih the North Carolina Center for Geographic Information and Analysis.

Native_Data_Set_Environment:

Z/I Imaging Orthopro 4.0, Windows 2000 SP2, Using GeoMedia 4.0 on an ISI workstation.

Data_Quality_Information:

Attribute_Accuracy:

Attribute_Accuracy_Report:

During photographic reproduction of the source photographs, limited analog dodging (radiometric editing) is performed to improve image quality. Analog dodging consists of holding back light from certain areas of the sensitized photographic material to avoid overexposure. The diapositive is inspected to ensure clarity and radiometric uniformity. Diapositive image brightness values are collected with a minimum of image quality manipulation. Image brightness values may deviate from the brightness values of the original images because of image value interpolation during the scanning and rectification processes. Radiometry is verified by visual inspection of the digital orthophoto with the original unrectified image to determine if the digital orthophoto has the same or better image quality as the original unrectified input image. Slight systematic radiometric differences can be detected between adjacent orthoimage files; these are due primarily to differences in source photograph capture dates and sun angles along flight lines when the aerial photographs were taken. These differences can be observed in an image's general lightness or darkness when it is compared to adjacent orthoimage file coverages. Tonal balancing may be performed over a group of images during the mosaicking process which may serve to lighten or darken adjacent images for better color tone matching.

This tile contains approximately 400-500 meters of void along the east edge of coverage.

Positional_Accuracy:

Horizontal_Positional_Accuracy:

Horizontal_Positional_Accuracy_Report:

The horizontal positional accuracy and the assurance of that accuracy depend, in part, on the accuracy of the data inputs to the rectification process. The location of existing USGS photoidentifiable ground control and contractor aerotriangulation points were evaluated on the Geotiff image and compared with their ground values in order to determine an overall accuracy for each test block of orthoimages within the project. After image coordinate measurement was completed for each block, an RMSE for the diagonal error was calculated for the orthoimages within the block. This value is an estimate of the horizontal accuracy of the tile expressed in meters.

Quantitative_Horizontal_Positional_Accuracy_Assessment:

Horizontal_Positional_Accuracy_Value: 0.90

Horizontal_Positional_Accuracy_Explanation:

Federal Geographic Data Committee, 1998, Geospatial Positioning Accuracy Standard, Part 3, National Standard for Spatial Data Accuracy, FGDC-STD-007.3-1998

Lineage:

Source_Information:

Source_Citation:

Citation_Information:

Originator: Sanborn of Colorado, LLC

Publication_Date: 2002

Title: RDU 1-8

Source_Scale_Denominator: 15000

Type_of_Source_Media: disc

Source_Time_Period_of_Content:

Time_Period_Information:

Single_Date/Time:

Calendar_Date: 20020328

Source_Currentness_Reference: gound condition

Source_Citation_Abbreviation: PHOTO

Source_Contribution:

True color stable-base aerial photography film flown at 7,500 feet above average ground elevation. Provides the imagery for the digital orthoimage.

Source_Information:

Source_Citation:

Citation_Information:

Originator: Sanborn of Colorado, LLC

Publication_Date: 2002

Title: RDU 1-9

Source_Scale_Denominator: 15000

Type_of_Source_Media: disc

Source_Time_Period_of_Content:

Time_Period_Information:

Single_Date/Time:

Calendar_Date: 20020328

Source_Currentness_Reference: gound condition

Source_Citation_Abbreviation: PHOTO

Source_Contribution:

True color stable-base aerial photography film flown at 7,500 feet above average ground elevation. Provides the imagery for the digital orthoimage.

Source_Information:

Source_Citation:

Citation_Information:

Originator:

Floodplain Mapping Program, North Carolina Division of Emergency Management.

Publication_Date: 20020531

Title: Garner, NC 10m LIDAR DEM

Type_of_Source_Media: disc

Source_Time_Period_of_Content:

Time_Period_Information:

Range_of_Dates/Times:

Beginning_Date: 200101

Ending_Date: 200103

Source_Currentness_Reference: ground condition

Source_Citation_Abbreviation: DEM

Source_Contribution:

USGS format elevation data with a 10m grid post interval and covering a 7.5- x 7.5-minute quadrangle in extent. Derived from LIDAR measurements obtained in 2001. Used to provide ground elevations for orthorectification process.

Source_Information:

Source_Citation:

Citation_Information:

Originator:

Floodplain Mapping Program, North Carolina Division of Emergency Management.

Publication_Date: 20020531

Title: Clayton, NC 10m LIDAR DEM

Type_of_Source_Media: disc

Source_Time_Period_of_Content:

Time_Period_Information:

Range_of_Dates/Times:

Beginning_Date: 200101

Ending_Date: 200103

Source_Currentness_Reference: ground condition

Source_Citation_Abbreviation: DEM

Source_Contribution:

USGS format elevation data with a 10m grid post interval and covering a 7.5- x 7.5-minute quadrangle in extent. Derived from LIDAR measurements obtained in 2001. Used to provide ground elevations for orthorectification process.

Source_Information:

Source_Citation:

Citation_Information:

Originator: Sanborn of Colorado, LLC

Publication_Date: Unpublished material

Title: Airborne GPS Control

Type_of_Source_Media: disc

Source_Time_Period_of_Content:

Time_Period_Information:

Single_Date/Time:

Calendar_Date: 20020328

Source_Currentness_Reference: ground condition

Source_Citation_Abbreviation: ABGPS

Source_Contribution:

Horizontal and vertical control used to establish positions and elevations for reference and correlation purposes and as input to the aerotriangulation process. Control consists of both Airborne GPS to provide camera station positions and photoidentifiable surveyed ground control for ground reference.

Source_Information:

Source_Citation:

Citation_Information:

Originator: US Geological Survey

Publication_Date: Unpublished material

Title: Aero-triangulation Control

Type_of_Source_Media: disc

Source_Time_Period_of_Content:

Time_Period_Information:

Single_Date/Time:

Calendar_Date: 20020328

Source_Currentness_Reference: ground condition

Source_Citation_Abbreviation: AT_CONTROL

Source_Contribution:

Horizontal and vertical check points and External Orientation Parameters. Check points consist of photoidentiable horizontal ground control. External Orientation Parameters derived through aero-triangulation are used as control input to the Orthorectification process.

Process_Step:

Process_Description:

Each image was scanned from film-stable source at a resolution of 20 micrometers. Airborne GPS provided the camera station X, Y, and Z coordinates and was used to control a softcopy aerotriangulation block solution. Available USGS photoidentifiable ground control was used to test the results of the aerotriangulation adjustment. External orientation parameters derived from the aerotriangulation solution were used to provide the horizontal control for each photograph. Vertical control for the orthorectification process was obtained from both LIDAR and existing USGS Digitial Elevation Models (DEM). During the orthorectification process, elevation data were extracted and resampled to meet user-specified intervals and bounds.

The orthorectified imagery is resampled to a 0.3 meter ground resolution with a ground extent of 1500- by 1500-meters. Each 1500- by 1500-meter orthoimage is generated from a mosaic created from multiple photographs. Tonal balancing is automatically performed over each work block of contiguous images during the mosaicking process. However, a single tonal balancing operation was not performed over the project area in its entirety. Orthorectification and mosaicking were performed using Z/I Imaging OrthoPro 4.00.00.05 running on Windows 2000 SP2. Resampling to 0.3 meter was done using cubic convolution. Individual orthoimages are bounded by UTM grid lines which are evenly divisible by 1500. Final output is as an uncompressed GeoTiff file.

All orthoimages are individually inspected for content, misalignments along mosaic seamlines, and void areas. No digital image dodging or enhancement was performed. Source information was collected and verified manually during the production process.

Process_Date: 20030611

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: 0.9996

Longitude_of_Central_Meridian: -81.0000

Latitude_of_Projection_Origin: 0.0

False_Easting: 500000

False_Northing: 0

Planar_Coordinate_Information:

Planar_Coordinate_Encoding_Method: row and column

Coordinate_Representation:

Abscissa_Resolution: 0.3

Ordinate_Resolution: 0.3

Planar_Distance_Units: meters

Geodetic_Model:

Horizontal_Datum_Name: North American Datum of 1983

Ellipsoid_Name: Geodetic Reference System 80

Semi-major_Axis: 6378137

Denominator_of_Flattening_Ratio: 298.2572221

Metadata_Reference_Information:

Metadata_Date: 20030827

Metadata_Contact:

Contact_Information:

Contact_Organization_Primary:

Contact_Organization: USGS

Contact_Address:

Address_Type: mailing

Address: EROS Data Center

City: Sioux Falls

State_or_Province: SD

Postal_Code: 57198-0001

Country: US

Contact_Voice_Telephone: 1-605-594-6151

Contact_TDD/TTY_Telephone: 1-605-594-6933

Contact_Facsimile_Telephone: 1-605-594-6589

Contact_Electronic_Mail_Address: custserv@usgs.gov

Hours_of_Service: Monday through Friday 8:00 AM to 4:00 PM (Central Time)

Metadata_Standard_Name: FGDC Content Standard for Digital Geospatial Metadata

Metadata_Standard_Version: FGDC-STD-001-1998