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Digital Orthophoto Quadrangles for Portions of Wyoming

Metadata:

Identification_Information: 
Citation:
Citation_Information:
Originator: U.S. Geological Survey
Publication_Date: unknown
Title: Digital Orthophoto Quadrangles for Portions of Wyoming
Geospatial_Data_Presentation_Form: remote-sensing image
Publication_Information:
Publication_Place: Reston, VA
Publisher: U.S. Geological Survey
Online_Linkage: <URL:http://www.sdvc.uwyo.edu/doqq>  
Description:
Abstract:
Orthophotos combine the image characteristics of a photograph with the geometric qualities of a map. The primary digital orthophotoquad (DOQ) is a 1-meter ground resolution, quarter-quadrangle (3.75-minutes of latitude by 3.75-minutes of longitude) image cast on the Universal Transverse Mercator Projection (UTM) on the North American Datum of 1983 (NAD83).The geographic extent of the DOQ is equivalent to a quarter-quad plus The overedge ranges a minimum of 50 meters to a maximum of 300 meters beyond the extremes of the primary and secondary corner points. The overedge is included to facilitate tonal matching for mosaicking and for the placement of the NAD83 and secondary datum corner ticks. The normal orientation of data is by lines (rows) and samples (columns). Each line contains a series of pixels ordered from west to east with the order of the lines from north to south. The standard, archived digital orthophoto is formatted as four ASCII header records, followed by a series of 8-bit binary image data records. The radiometric image brightness values are stored as 256 gray levels ranging from 0 to 255.

The standard distribution format of DOQs will be BIL images on CD-ROM or compressed JPEG for download. Currently only images for the Jackson Hole area via the Spatial Data and Visualization Center clearinghouse. An on-line image browser is available (see the on-line linkage above) for viewing available images for the state and may include downloading capability as more images come on-line.

The compressed JPEG format will exhibit some radiometric differences when compared to its uncompressed original but will retain the geometry of the uncompressed DOQ.  

Purpose:
DOQ's serve a variety of purposes, from interim maps to field references for earth science investigations and analysis. The DOQ is useful as a layer of a geographic information system and as a tool for revision of digital line graphs and topographic maps.
Time_Period_of_Content:
Time_Period_Information:
Range_of_Dates/Times:
Beginning_Date: 19940222
Ending_Date: present
Currentness_Reference: ground condition  
Status:
Progress: In work
Maintenance_and_Update_Frequency: irregular  
Spatial_Domain:
Bounding_Coordinates:
West_Bounding_Coordinate: -111.36
East_Bounding_Coordinate: -107
North_Bounding_Coordinate: 44
South_Bounding_Coordinate: 43  
Keywords:
Theme:
Theme_Keyword_Thesaurus: None
Theme_Keyword: DOQ
Theme_Keyword: DOQQ
Theme_Keyword: digital orthophoto
Theme_Keyword: digital orthophotoquad
Theme_Keyword: digital image map
Theme_Keyword: aerial photograph
Theme_Keyword: rectified photograph
Theme_Keyword: rectified image
Theme_Keyword: orthophoto
Theme_Keyword: quarter-quadrangle orthophoto
Theme_Keyword: 1-meter orthophoto
Place:
Place_Keyword_Thesaurus:
U.S. Department of Commerce, 1977, Countries, dependencies, areas of special sovereignty, and their principal administrative divisions (Federal Information Processing Standard 10-3):Washington, D.C., National Institute of Standards and Technology.
Place_Keyword: US
Place_Keyword: CA
Place_Keyword: MX
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 5-2): Washington, D. C., National Institute of Standards and Technology.
Place_Keyword: FIPS code of State or Province
Place:
Place_Keyword_Thesaurus:
U.S. Department of Commerce,1990, Counties and equivalent entities of The United States, its possessions, and associated areas (Federal Information Processing Standard 6-4): Washington, D.C. National Institute of Standards and Technology.
Place_Keyword: FIPS code for county or counties.  
Access_Constraints: None  
Use_Constraints:

None. Acknowledgement of the U.S. Geological Survey would be appreciated in products derived from these data.

Data_Quality_Information:  

Attribute_Accuracy:
Attribute_Accuracy_Report:
During photographic reproduction of the source photography, limited analog dodging 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 insure clarity and radiometric uniformity. Diapositive image brightness values are collected with a minimum of image quality manipulation. Image brightness values may deviate from brightness values of the original imagery due to image value interpolation during the scanning and rectification processes. Radiometry is verified by visual inspection of the digital orthophoto quadrangle 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 DOQ files due primarily to differences in source photography capture dates and sun angles of aerial photography along flight lines. These differences can be observed in an image's general lightness or darkness when compared to adjacent DOQ file coverages.  
Logical_Consistency_Report:
All DOQ header data and image file sizes are validated by the Tape Validation System (TVS) software prior to archiving in the National Digital Cartographic Data Base (NDCDB). This validation procedure assures correct physical format and field values for header record elements. Logical relationships between header record elements are tested.  
Completeness_Report:
All DOQ imagery is visually inspected for completeness to ensure that no gaps, or image misplacement exist in the 3.75' image area or in overedge coverage. DOQ images may be derived by mosaicking multiple images, in order to insure complete coverage. All DOQ's are cloud free within the 3.75' image area. Some clouds may, very infrequently, be encountered only in the overedge coverage. Source photography is leaf-off in deciduous vegetation regions. Void areas having a radiometric value of zero and appearing black may exist. These are areas for which no photographic source is available or result from image transformation from other planimetric systems to the Universal Transverse Mercator (UTM). In the latter case, the void sliver areas are on the outside edges of the overedge area. The data set field content of each DOQ header record element is validated to assure completeness prior to archiving in the NDCDB.  
Positional_Accuracy:
Horizontal_Positional_Accuracy:
Horizontal_Positional_Accuracy_Report:
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 the verified USGS format DEM is equivalent to or better than a USGS 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 Staandards (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. Horizontal positional accuracy is determined by the Orthophoto Accuracy (ORACC) software program for DOQ data produced by the National Mapping Division. The program determines the accuracy by finding the line and sample coordinates of the passpoints in the DOQ and fitting these to their ground coordinates to develop a root mean square error (RMSE). From 4 to 9 points are checked. As a further accuracy test, the image line and sample coordinates of the DEM corners are transformed and compared with the actual X,Y DEM corner values to determine if they are within the RMSE. Additional information on this testing procedure can be found in U.S. Department of the Interior, U.S. Geological Survey, 1993, Technical Instructions, ORACC Users Manual (draft): Reston, VA. Adjacent DOQ's, 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. Field investigations to validate DOQ positional accuracy reliabilty are periodically conducted by the USGS, National Mapping Division, Geometronics Standards Section. DOQ's produced by cooperators and contractors use similarly approved RMSE test procedures.  
Lineage:
Source_Information:
Source_Citation:
Citation_Information:
Originator: U.S. Geological Survey
Publication_Date: unknown
Title: digital elevation model
Geospatial_Data_Presentation_Form: map
Publication_Information:
Publication_Place: Reston, VA
Publisher: U.S. Geological Survey
Type_of_Source_Media: cartridge tape
Source_Time_Period_of_Content:
Time_Period_Information:
Range_of_Dates/Times:
Beginning_Date: 19880805
Ending_Date: present
Source_Currentness_Reference: ground condition
Source_Citation_Abbreviation: DEM1
Source_Contribution:
Elevation data in the form of an ortho-DEM regridded to user-specified intervals and bounds.
Source_Information:
Source_Citation:
Citation_Information:
Originator: U.S. Geological Survey
Publication_Date:
Title: photo ID number
Geospatial_Data_Presentation_Form: remote-sensing image
Publication_Information:
Publication_Place: Reston, VA
Publisher: U.S. Geological Survey
Source_Scale_Denominator: 40000
Type_of_Source_Media: cartridge tape
Source_Time_Period_of_Content:
Time_Period_Information:
Range_of_Dates/Times:
Beginning_Date: various
Ending_Date: various
Source_Currentness_Reference: ground condition
Source_Citation_Abbreviation: PHOTO1
Source_Contribution:
Panchromatic black and white (or color infra-red) NAPP or NAPP-like photograph. NAPP photographs are centered on the DOQ coverage area.
Source_Information:
Source_Citation:
Citation_Information:
Originator: U.S. Geological Survey
Publication_Date: Unpublished material
Title: project ground and photo control
Geospatial_Data_Presentation_Form: remote-sensing image
Publication_Information:
Publication_Place: Reston, VA
Publisher: U.S. Geological Survey
Type_of_Source_Media: various media
Source_Time_Period_of_Content:
Time_Period_Information:
Range_of_Dates/Times:
Beginning_Date: various
Ending_Date: various
Source_Currentness_Reference: ground condition
Source_Citation_Abbreviation: CONTROL_INPUT
Source_Contribution:
Horizontal and vertical control used to establish positions and elevations for reference and correlation purposes.
Source_Information:
Source_Citation:
Citation_Information:
Originator: U.S. Geological Survey
Publication_Date: Unpublished material
Title: report of calibration
Geospatial_Data_Presentation_Form: remote-sensing image
Publication_Information:
Publication_Place: Reston, VA
Publisher: U.S. Geological Survey
Type_of_Source_Media: disc, paper
Source_Time_Period_of_Content:
Time_Period_Information:
Range_of_Dates/Times:
Beginning_Date: various
Ending_Date: various
Source_Currentness_Reference:
Date of the camera calibration associated with the source photography
Source_Citation_Abbreviation: CAMERA_INPUT
Source_Contribution: camera calibration parameters
Process_Step:
Process_Description:
The production procedures, instrumentation, hardware and software used in the collection of standard USGS DOQ's vary depending on systems used at the contract, cooperator or USGS production sites. The majority of DOQ datasets are acquired through government contract. The process step describes, in general, the process used in the production of standard USGS DOQ data sets.

The rectification process requires, as input, a user parameter file to control the rectification process, a digital elevation model (DEM1) gridded to user specified bounds, projection, zone, datum and X-Y units, a scanned digital image file (PHOTO1) covering the same area as the DEM, ground X-Y-Z point values (CONTROL_INPUT) and their conjugate photo coordinates in the camera coordinate system, and measurements of the fiducial marks (CAMERA_INPUT) in the digitized image.

The camera calibration report (CAMERA_INPUT) provides the focal length of the camera and the distances in millimeters from the camera's optical center to the camera's 8 fiducial marks. These marks define the frame of reference for spatial measurements made from the photograph. Ground control points (CONTROL_INPUT) acquired from ground surveys or developed in aerotriangulation, are third order class 1 or better, and meet National Map Accuracy Standard (NMAS) for 1:12,000-scale. Ground control points are in the Universal Transverse Mercator or the State Plane Coordinate System on NAD83. Horizontal and vertical residuals of aerotriangulated tie-points are equal to or less than 2.5 meters. Standard aerotriangulation passpoint configuration consists of 9 ground control points, one near each corner, one at the center near each side and 1 near the center of the photograph, are used. The conjugate positions of the ground control points on the photograph are measured and recorded in camera coordinates.

The raster image file (PHOTO_1) is created by scanning an aerial photograph film diapositive with a precision image scanner. An aperture of approximately 25 to 32 microns is used, with an aperture no greater than 32 microns permitted. Using 1:40,000-scale photographs, a 25-micron scan aperture equates to a ground resolution of 1-meter. The scanner converts the photographic image densities to gray scale values ranging from 0 to 255 for black and white photographs. Scan files with ground resolution less than 1 meter or greater than 1 meter but less than 1.28 meters are resampled to 1 meter.

The principal elevation data source (DEM1) are standard DEM datasets from the National Digital Cartographic Data Base (NDCDB). DEM's that meet USGS standards are also produced by contractors to fulfill DOQ production requirements and are subsequently archived in the NDCDB. All DEM data is equivalent to or better than USGS DEM standard level 1. The DEM used in the production of DOQ's generally has a 30-meter grid post spacing and possesses a vertical RMSE of 7-meters or less. A DEM covering the extent of the photograph is used for the rectification. The DEM is traversed from user-selected minimum to maximum X-Y values and the DEM X-Y-Z values are used to find pixel coordinates in the digitized photograph using transformations mentioned above. For each raster image cell subdivision, a brightness or gray-scale value is obtained using nearest neighbor, bilinear, or cubic convolution resampling of the scanned image. The pixel processing algorithm is indicated in the header file . An inverse transformation relates the image coordinates referenced to the fiducial coordinate space back to scanner coordinate space. For those areas for which a 7.5-minute DEM is unavailable and relief differences are less than 150 feet, a planar-DEM (slope-plane substitute grid) may be used.

Rectification Process: The photo control points and focal length are iteratively fitted to their conjugate ground control points using a single photo space resection equation. From this mathematical fit is obtained a rotation matrix of constants about the three axes of the camera. This rotation matrix can then be used to find the photograph or camera coordinates of any other ground X-Y-Z point. Next a two dimensional fit is made between the measured fiducial marks on the digitized photograph and their conjugate camera coordinates. Transformation constants are developed from the fit and the camera or photo coordinates are used in reverse to find their conjugate pixel coordiates on the digitized photograph.

Quality Control: All data is inspected according to a quality control plan. DOQ contractors must meet DOQ standards for attribute accuracy, logical consistency, data completeness and horizontal positional accuracy. During the initial production phase, all rectification inputs and DOQ data sets are inspected for conformance to standards. After a production source demonstrates high quality, inspections will be made to 10% of delivery lots (40 DOQs per lot). All DOQ's are visually inspected for gross positional errors and tested for physical format standards.

Source_Used_Citation_Abbreviation: DEM1, PHOTO1, CONTROL_INPUT, CAMERA_INPUT
Process_Date:  
Process_Step:
Process_Description:
Digital orthophotography in Band Interleaved by Line (.bil) format was converted to .jpg (.jfif) compressed format using the Arc/Info command CONVERTIMAGE. JFIF (JPEG File Interchange Format) is an image which was created to store image data using the JPEG compression method. JPEG compression can obtain high compression ratios, but may cause some data loss. Pixel values will be slightly different after decompression. Arc/Info JFIF compression uses a fixed 15:1 compression ratio, which gives minimal image degradation on most files. Unlike uncompressed DOQ's the compressed DOQ does not contain an attached header record as data compression corrupts ASCII text.
Source_Used_Citation_Abbreviation: none
Process_Date:

 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: 12-13
Transverse_Mercator:
Scale_Factor_at_Central_Meridian: .09996
Longitude_of_Central_Meridian: -107
Latitude_of_Projection_Origin: 0.0
False_Easting: 500000.
False_Northing: 0.0
Planar_Coordinate_Information:
Planar_Coordinate_Encoding_Method: row and column
Coordinate_Representation:
Abscissa_Resolution: 1
Ordinate_Resolution: 1
Planar_Distance_Units: meters
Geodetic_Model:
Horizontal_Datum_Name: North American Datum 1983
Ellipsoid_Name: Geodetic Reference System 80
Semi-major_Axis: 6378137
Denominator_of_Flattening_Ratio: 298.257  
Entity_and_Attribute_Information:  
Overview_Description:
Entity_and_Attribute_Overview:
For DOQ's from panchromatic source each pixel contains an 8-bit gray-scale value between 0-255. A value of 0 represents the color black while a value of 255 represents the color white. All values between 0 and 255 are repesented as a shade of gray varying from black to white. For color-infrared and natural color DOQs' a digital number from 0 to 255 will also be asssigned to each pixel but that number will refer to a color look-up table which will contain the RGB red, blue and green (RGB) values, each from 0 to 255, for that digital number. Areas where the rectification process is incomplete due to incomplete data (i.e., lack of elevation data, gaps), are represented with the numeric value of 0.
Entity_and_Attribute_Detail_Citation:
U.S. Department of the Interior, U.S. Geological Survey, 1992, Standards for digital orthophotos: Reston, VA. A hypertext version is available at: <URL:http://mapping.usgs.gov/www/ti/DOQ/standards_doq.html>

Softcopy in WordPerfect format is available at: <URL:ftp://mapping.usgs.gov/pub/ti/DOQ/doqstnds/doq1_12-96.wp6> <URL:ftp://mapping.usgs.gov/pub/ti/DOQ/doqstnds/doq2_12-96.wp6>

Softcopy in Portable Document Format (PDF) is available at: <URL:ftp://mapping.usgs.gov/pub/ti/DOQ/doqstnds/usgsdoq.pdf>  

Distribution_Information:
Distributor:
Contact_Information:
Contact_Person_Primary:
Contact_Person: Data Manager
Contact_Organization: Spatial Data and Visualization Center
Contact_Address:
Address_Type: mailing address
Address: Box 4008 University Station
City: Laramie
State_or_Province: Wyoming
Country: USA
Postal_Code: 82071
Contact_Voice_Telephone: 307-766-2751
Contact_Electronic_Mail_Address: n/a
Distribution_Liability:
Although these data have been processed successfully on a computer system at the U.S. Geological Survey no warranty expressed or implied is made by the USGS regarding the utility of the data on any other system, nor shall the act of distribution constitute any such warranty.  
Standard_Order_Process:
Digital_Form:
Digital_Transfer_Information:
Format_Name: Compressed USGS DOQ in JPEG format.
Transfer_Size: 5
Digital_Transfer_Option:
Online_Option:
Computer_Contact_Information:
Network_Address:
Network_Resource_Name: ftp.sdvc.uwyo.edu or <http://www.sdvc.uwyo.edu/clearinghouse>
Access_Instructions: <http://www.sdvc.uwyo.edu/clearinghouse/howto.html>
Online_Computer_and_Operating_System:
Both the ftp and WWW server which this data is available from is a Silicon Graphics Challenge server, running the IRIX 6.2 UNIX operating system.
Fees:
No fees are required for downloading the data that is on-line. Some fees may be required to cover costs of tapes if data is required on CD-ROM or tape media. 
Metadata_Reference_Information:
Metadata_Date: 199805
Metadata_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: Margo Berendsen
Contact_Address:
Address_Type: mailing address
Address: Box 4008 University Station
City: Laramie
State_or_Province: Wyoming
Postal_Code: 82071
Country: USA
Contact_Voice_Telephone: 307-766-2735
Contact_Electronic_Mail_Address: meh@uwyo.edu
Metadata_Standard_Name: FGDC Content Standards for Digital Geospatial Metadata
Metadata_Standard_Version: FGDC-STD-001-1998

Generated by mp version 2.4.13 on Mon Sep 18 14:39:46 2000