2004 Digital Orthophoto Quarter Quadrangles for Louisiana

Metadata:

• Identification_Information
• Data_Quality_Information
• Spatial_Data_Organization_Information
• Spatial_Reference_Information
• Distribution_Information
• Metadata_Reference_Information

Identification_Information:

Citation:

Citation_Information:

Originator: U.S. Geological Survey, National Wetlands Research Center

Publication_Date: 2005

Title: 2004 Digital Orthophoto Quarter Quadrangles for Louisiana

Geospatial_Data_Presentation_Form: raster digital data

Publication_Information:

Publication_Place: Lafayette, LA

Publisher: USGS, National Wetlands Research Center

Online_Linkage: <http://www.lacoast.gov>

Description:

Abstract:

This data set consists of the 2004 digital orthophoto quarter quadrangles for the state of Louisiana. The individual images were not altered in any way; the images were merged into a larger quadrangle. In some cases, individual frames had to be reprojected from UTM zone 16 to UTM zone 15. From the original metadata - A DOQQ is a raster image in which displacement in the image caused by sensor orientation and terrain relied has been removed. A DOQQ combines the image characteristics of a photograph with the geometrics qualities of a map. The geographic extent of the DOQQ is equivalent to a quarter of a 7.5 minute map (3.75 minutes of latitude and longitude) with overedge. The overedge ranges from a minimum of 50 meters to 300 meters beyond the extremes of the primary and secondary corner ticks. DOQQs are produced with a l-meter ground sample distance (GSD) and are cast on the Universal Transverse Mercator (UTM) projection on the North American Datum of 1983 (NAD83). Primary (solid) and secondary (dashed) corner ticks are burned into the image to indicate the geographic corners of the DOQQ. The primary ticks always show the NAD83 corners. The secondary ticks show either the NAD27 or the local horizontal datum in use in a specific area. Each DOQQ is produced to meet a National Map Accuracy Standard (NMAS) for 1:12000 scale maps (10.16 meters radial error at a 90% probability). DOQQs are nominally produced from the National Aerial Photography Program (NAPP) source imagery flown at 20000 feet above average ground using a single source image for each DOQQ. NAPP imagery is flown leaf-off in deciduous vegetation regions.

Purpose: To provide imagery for Louisiana

Supplemental_Information:

This metadata was generated using information provided in the original metadata records (from USGS Geography Division and Aero-Metrics) for the quarter quadrangles. Since the data were not altered in any way, the information from the original data documentation is used. It would be advisable to contact the originator of the data for further information not found in this record or for specific information on the individual quarter quadrangles.

Time_Period_of_Content:

Time_Period_Information:

Range_of_Dates/Times:

Beginning_Date: 20040125

Ending_Date: 20040313

Currentness_Reference: publication date

Status:

Progress: In work

Maintenance_and_Update_Frequency: Irregular

Spatial_Domain:

Bounding_Coordinates:

West_Bounding_Coordinate: -92.00

East_Bounding_Coordinate: -91.00

North_Bounding_Coordinate: 30.50

South_Bounding_Coordinate: 30.00

Keywords:

Theme:

Theme_Keyword_Thesaurus: None

Theme_Keyword: DOQQ

Theme_Keyword: digitial orthophoto quarter quadrangles

Theme_Keyword: quarter quadrangles

Theme_Keyword: imagery

Theme_Keyword: CIR

Theme_Keyword: color infrared

Theme_Keyword: aerial photography

Theme_Keyword: NAPP

Theme_Keyword: orthophoto

Theme_Keyword: rectified photography

Theme_Keyword: rectification

Theme_Keyword: 1-meter orthophoto

Theme_Keyword: 3.75x3.75 minute orthophoto

Place:

Place_Keyword_Thesaurus: None

Place_Keyword: Louisiana

Place_Keyword: LA

Access_Constraints:

It is strongly recommended that these data are directly acquired from the distributor described above or from another USGS server and not indirectly through other sources which may have changed the data in some way. The distributor makes no claim as to the data's suitability for other purposes.

Use_Constraints:

Acknowledgement of the U.S. Geological Survey, National Wetlands Research Center as a data source would be appreciated in products developed from these data, and such acknowledgement as is standard for citation and legal practices for data source is expected by users of these data. Sharing new data layers developed directly from these data would be appreciated by U.S. Geological Survey, National Wetlands Research Center staff. Users should be aware that comparison with other data sets for the same area from other time periods may be inaccurate due to inconsistencies resulting from changes in mapping conventions, data collection procedures, and computer processes over time. The distributor shall not be liable for improper or incorrect use of these data, based on the description of appropriate/inappropriate uses described in this metadata document. These data are not legal documents and are not to be used as such

Point_of_Contact:

Contact_Information:

Contact_Organization_Primary:

Contact_Organization: U.S. Geological Survey, National Wetlands Research Center

Contact_Person: Calvin "Pat" O'Neil

Contact_Position: Principal Investigator

Contact_Address:

Address_Type: mailing and physical address

Address: 700 Cajundome Blvd

City: Lafayette

State_or_Province: LA

Postal_Code: 70506

Country: USA

Contact_Voice_Telephone: 337 266-8699

Contact_Facsimile_Telephone: 337 266-8513

Contact_Electronic_Mail_Address: pat_o'neil@usgs.gov

Data_Quality_Information:

Attribute_Accuracy:

Attribute_Accuracy_Report:

From the original metadata - Scanning was done from the negative film at 21 microns. Image brightness values may deviate from the original images because of image value interpolation during scanning and rectification processes. Radiometry is verified by visual inspection of the digital orthophoto. Where possible, radiometry is verified by visual inspection of the digital orthophoto with the original unrectified image. Slight systematic radiometric differences may exist between adjacent orthoimage files; these are due primarily to differences in source image capture dates and sun angles along flight lines. 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.

Logical_Consistency_Report:

From the original metadata - All DOQQ header data and image file sizes are validated using USGS software before being archived. This validation process ensures correct physical format and field values for header elements. Logical relationships between header elements are tested. Overlap regions between individual DOQQs are visually inspected for excessive horizontal displacement.

Completeness_Report:

From the original metadata - DOQQ images are visually inspected for completeness to ensure that no gaps or image misplacements exist within the 3.75 minute image area or the overedge coverage. DOQQs can be derived by mosaicking multiple images to ensure complete coverage. DOQQs are nomially produced from National Aerial Photography Program (NAPP) source imagery flown at 20,000 feet above average ground using a single source image for each DOQQ. NAPP imagery is flown leaf-off in deciduous vegetation regions. Source imagery is nomially cloud free. Coastal areas and international boundary regions may have areas without images (void areas) in parts of the coverage. These void areas have a radiometric value of either zero (black) or 128 (uniform gray). DOQQs nomially are produced with overedge coverage. This coverage is variable and may range from a minimum of 50 meters to a maximum of 300 meters beyond the extremes of the primary or secondary corners. The resulting DOQQ is a rectangle whose size may vary in relation to adjoining DOQQs.

Positional_Accuracy:

Horizontal_Positional_Accuracy:

Horizontal_Positional_Accuracy_Report:

From the original metadata - The DOQQ horizontal positional accuracy and the assurance of that accuracy depend, in part, on the accuracy of the data inputs to the rectification process (elevation data, aerotriangulation control and methods, camera calibration, scanner calibration, and source imagery parameters). DOQQs are produced to meet NMAS requirements for 1:12,000 scale products. DOQQs are deduced to meet this accuracy if specific production processes are followed which include the use of 1:40,000 scale imagery or better meeting NAPP specification, elevation data with a vertical root mean square error (RMSE) of 7 meters or better, and aerotriangulation results with an RMSW of 2 meters or better. This deduction is based on extensive field accuracy checking during the initial years when the production process was designed and proven. Horizontal accuracy is determined using USGS software which automatically fits the passpoints in a DOQQ to their actual ground coordinates and determining an RMSE. Contractors and partners may use similarily approved RMSE test procedures. The RMSE value is reported in meters. Qualtiy control (QC) ground points were established throughout the project area. These photo identifiable points were ground check points provided by the USGS. The locations of the QC ground points were compared to their positions on the rectified ortho images. The resulting X and Y residuals were used to calculate the RMSE XY. Adjacent DOQQs, when displayed together in a common coordinate system, may exhibit positional discrepancies across common DOQQ boundaries. Linear features such as streets, may not be continuous. However, these edge mismatches still conform to the NMAS accuracy specification. The USGS, Geography Discipline, periodically conducts field investigations to validate the reliability of DOQQ positional accuracy.

Quantitative_Horizontal_Positional_Accuracy_Assessment:

Horizontal_Positional_Accuracy_Value: 1.8480

Horizontal_Positional_Accuracy_Explanation: National Standard for Spatial Data Accuracy

Lineage:

Process_Step:

Process_Description:

Creation of DOQQs - from the original metadata - The rectification process requires, as input, a digital elevation model (DEM) gridded to user-specified bounds, a scanned digital image file (PHOTO), and external orientation parameters for the aerial photograph which are typically derived from aerotriangulation (ATCONTROL). Each image was scanned from film-stable source at a resolution of 21 microns. The scanned images, ABGPS data, ground check points data, and camera calibration data were used as inputs to the Zeiss/Intergraph ImageStation Automatic Triangulation (ISAT) softcopy program. ISAT correlated iamge points and aerotriangulated the block of images to create the exposure station 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 existing USGS DEM. During the orthorectification process, elevation data were extracted and resampled to meet user-specified intervals and bounds. Each DOQQ was produced by mosaicking multiple images. Tonal balancing was performed across mosaic lines to provide a more naturally appearing final product. The orthorectified imagery is resampled to a 1-meter ground resolution with a ground extent of 3.75 minutes in latitude and in longitude. Up to 300 meters +/- 30 meters of overedge coverage beyond the extreme primary and secondary corner ticks is included in the DOQQ. Quarter quad corner ticks, representing both NAD83 and NAD27 horizontal datum are burned into the DOQQ image. An easily viewable ASCII text header is added to the DOQQ. This header is padded to the same length as a line of image data. The header contains information on structure, display, georefencing, and production information. Panchromatic images are written out using an 8-bit BIL structure. Color images are written out using a 24-bit (RGB) BIP structure. Orthorectification was performed using Z/I Imaging Orthopro software. Resampling to 1-meter GSD was done using cubic convolution. All orthoimages are individually inspected for content, misalignments along mosiac seamlines, and void areas. Digital images dodging or enhancement was performed. Source information was collected and verified manually durng the production process.

Process_Date: 2004-2005

Process_Step:

Process_Description:

Data management - The individual quarter quads were loaded into SDE according to their associated 1:100,000 quadrangles. The first parameter was used to keep the first pixel loaded for any areas of overlap.

Process_Date: 2005

Spatial_Data_Organization_Information:

Direct_Spatial_Reference_Method: Raster

Raster_Object_Information:

Raster_Object_Type: Pixel

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: 0.9996

Longitude_of_Central_Meridian: -93.0

Latitude_of_Projection_Origin: 0.0

False_Easting: 500000

False_Northing: 0.0

Planar_Coordinate_Information:

Planar_Coordinate_Encoding_Method: coordinate pair

Coordinate_Representation:

Abscissa_Resolution: 1

Ordinate_Resolution: 1

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

Distribution_Information:

Distributor:

Contact_Information:

Contact_Organization_Primary:

Contact_Organization: U.S. Geological Survey, National Wetlands Research Center

Contact_Position: Database Administrator

Contact_Address:

Address_Type: mailing and physical address

Address: 700 Cajundome Blvd

City: Lafayette

State_or_Province: LA

Postal_Code: 70506

Country: USA

Contact_Voice_Telephone: 337 266-8500

Contact_Facsimile_Telephone: 337 266-8513

Distribution_Liability:

Although these data have been processed successfully on a computer system at the U.S. Geological Survey, National Wetlands Research Center, no warranty expressed or implied is made regarding the accuracy or utility of the data on any other system or for general or scientific purposes, nor shall the act of distribution constitute any such warranty. This disclaimer applies both to individual use of the data and aggregate use with other data. It is strongly recommended that these data are directly acquired from a USGS server, and not indirectly through other sources which may have changed the data in some way. It is also strongly recommended that careful attention be paid to the contents of the metadata document associated with these data. U.S. Geological Survey, National Wetlands Research Center shall not be held liable for improper or incorrect use of the data, including, without limitations, the implied warranties or merchantability and fitness for a particular purpose. Also, use of trade names or commerical products in these metadata is solely for the purpose of providing specific information, and does not imply recommendation or endorsement by the U.S. Government. Any downloading and use of these data signifies a user's agreement to comprehension and compliance of the U.S. Geological Survey, National Wetlands Research Center Standard Disclaimer. Insure all portions of metadata are read and clearly understood before using these data in order to protect both user and U.S. Geological Survey, National Wetlands Research Center interests.

Standard_Order_Process:

Digital_Form:

Digital_Transfer_Information:

Format_Name: JPEG

Digital_Transfer_Option:

Online_Option:

Computer_Contact_Information:

Network_Address:

Network_Resource_Name: <http://www.lacoast.gov>

Fees: None, if available online

Metadata_Reference_Information:

Metadata_Date: 20050614

Metadata_Contact:

Contact_Information:

Contact_Organization_Primary:

Contact_Organization: U.S. Geological Survey, National Wetlands Research Center

Contact_Position: Metadata Specialist

Contact_Address:

Address_Type: mailing and physical address

Address: 700 Cajundome Blvd

City: Lafayette

State_or_Province: LA

Postal_Code: 70506

Country: USA

Contact_Voice_Telephone: 337 266-8500

Contact_Facsimile_Telephone: 337 266-8513

Metadata_Standard_Name: FGDC Content Standards for Digital Geospatial Metadata

Metadata_Standard_Version: FGDC-STD-001-1998

Metadata_Access_Constraints:

There are no access limitations on acquiring the metadata document. Metadata can be accessed through the U.S. Geological Survey, National Wetlands Research Center website or the Federal Geographic Data Committee (FGDC) metadata clearinghouse

Metadata_Use_Constraints:

Acknowledgement of the U.S. Geological Survey, National Wetlands Research Center as the metadata source would be appreciated. Please cite the original metadata when using portions of the record to create a similar record for slightly altered data for reprojection or subsetting.