Identification_Information: 
     Citation: 
          Citation_Information: 
               Originator: U.S. Geological Survey 
               Publication_Date: Unknown 
               Title: Digital Orthophoto Quadrangles 
               Geospatial_Data_Presentation_Form: remote-sensing image 
               Publication_Information: 
                    Publication_Place: Reston, VA 
                    Publisher: U.S. Geological Survey 
     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
               metadata provided in the digital orthophoto contain a wide range of descriptive information including format source information, production instrumentation and dates,
               and data to assist with displaying and georeferencing the image. The standard distribution format of DOQs will be JPEG compressed images on CD-ROM by
               counties or special regions. The reconstituted image from the CD-ROM will exhibit some radiometric differences when compared to its uncompressed original but will
               retain the geometry of the uncompressed DOQ. Uncompressed DOQs are distributed on tape. 
          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: -103.125000 
               East_Bounding_Coordinate: -94.375000 
               North_Bounding_Coordinate: 37.000000 
               South_Bounding_Coordinate: 33.500000 
     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 
               Theme_Keyword: 2-meter orhtophoto 
               Theme_Keyword: 3.75- x 3.75-minute orthophoto 
               Theme_Keyword: 7.5- x 7.5-minute 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_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_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. 

     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: Unknown 
                         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: Unknown 
                              Ending_Date: Present 
                    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: Unknown 
                              Ending_Date: Present 
                    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: Unknown 
                              Ending_Date: Present 
                    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 
               Process_Date: Unknown 



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: 10-19 
                         Transverse_Mercator: 
                              Scale_Factor_at_Central_Meridian: .09996 
                              Longitude_of_Central_Meridian: -123 00 00 
                              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, guide for digital orthophotos: Reston, VA. 

               A hypertext version is available at:  

               U.S. Department of the Interior, U.S. Geological Survey, 1992, Standards for digital orthophotos: Reston, VA. 

               Softcopies in ASCII, WordPerfect, and PostScript format are available at:  



Distribution_Information: 
     Distributor: 
          Contact_Information: 
               Contact_Organization_Primary: 
                    Contact_Organization: Earth Science Information Center, U.S. Geological Survey 
               Contact_Address: 
                    Address_Type: mailing address 
                    Address: 
                         Complete list of Earth Science Information Centers at: 

                          

                    Address: 507 National Center 
                    City: Reston 
                    State_or_Province: VA 
                    Postal_Code: 20192 
               Contact_Voice_Telephone: 1-888-ASK-USGS 
               Hours_of_Service: 0800-1600 
               Contact_Instructions: 
                    In addition to the address above there are other ESIC offices throughout the country. A full list of these offices is at: 

                     

     Resource_Description: Digital Orthophotoquad 
     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. The USGS will warrant the delivery of this product in
          computer-readable format and will offer appropriate adjustment of credit when the product is determined unreadable by correctly adjusted computer input peripherals, or
          when the physical medium is delivered in damaged condition. Requests for adjustments of credit must be made within 90 days from the date of this shipment from the
          ordering site. 
     Standard_Order_Process: 
          Digital_Form: 
               Digital_Transfer_Information: 
                    Format_Name: USGS_DOQ 
                    Format_Information_Content: 
                         USGS uncompressed DOQ: The uncompressed USGS DOQ is a raw binary image file preceded by a metadata header record which consists of four
                         400-byte ACSII records, each blank padded to equal the length of a single line of image data. 
                    Transfer_Size: 45 
               Digital_Transfer_Option: 
                    Offline_Option: 
                         Offline_Media: 8-mm helical-scan cartridge tape 
                         Recording_Format: 
                              Unlabelled, uncompressed Unix DD archive format. Standard block size: 30,270, but can be provided at 2,048 or multiples of 2,048. 
                    Offline_Option: 
                         Offline_Media: 3480 cartridge tape 
                         Recording_Format: 
                              Unlabelled, uncompressed Unix DD archive format. Blocksize = 6250 cpi. 
          Fees: 
               The online copy of the data set (when available electronically) may be accessed without charge. For cartridge, cassette and CD-ROM the costs are available at: 

                

     Standard_Order_Process: 
          Digital_Form: 
               Digital_Transfer_Information: 
                    Format_Name: Compressed USGS DOQ in JPEG format. 
                    Format_Information_Content: 
                         The USGS compressed DOQ is an IJG JPEG-compressed file. JPEG is a lossy compression technique. Unlike uncompressed DOQ's the compressed
                         DOQ does not contain an attached header record as data compression corrupts ASCII text. A separate metadata file accompanies the compressed
                         image file. The compressed data are distributed on CD-ROM, generally by county. However, some CD's may contain regions or partial counties and
                         some counties may require multiple CD-ROM's. The presence of a DOQ in the NDCDB does not necessarily indicate the file is available on a
                         compressed, county based CD-ROM. 
                    File_Decompression_Technique: 
                         The algorithm employed by USGS for compressing DOQs is IJG JPEG, Version 4.0. This is a lossy compression using a standard Q or quality factor of
                         30. 
                    Transfer_Size: 5 
               Digital_Transfer_Option: 
                    Offline_Option: 
                         Offline_Media: CD-ROM 
                         Recording_Format: ISO 9660 
                         Compatibility_Information: 
                              This CD-ROM can be used with all computer operating systems that support CD-ROM as a logical storage device. All text files on this disc are
                              in ASCII format. Data files are in ASCII or binary format. 
          Fees: 
               The cost for these CD-ROM products is available at: 

                

          Ordering_Instructions: 
               Dataset searching and ordering capabilities are available through the Global Land Information System (GLIS) at: 

                



Metadata_Reference_Information: 
     Metadata_Date: 199501 
     Metadata_Contact: 
          Contact_Information: 
               Contact_Organization_Primary: 
                    Contact_Organization: U.S. Geological Survey 
               Contact_Address: 
                    Address_Type: mailing address 
                    Address: 508 National Center 
                    City: Reston 
                    State_or_Province: VA 
                    Postal_Code: 20192 
               Contact_Voice_Telephone: 703 648 4543 
     Metadata_Standard_Name: Content Standards for Digital Geospatial Metadata 
     Metadata_Standard_Version: FGDC-STD-001-1998 
     Metadata_Security_Information: 
          Metadata_Security_Classification_System: None 
          Metadata_Security_Classification: Unclassified 
          Metadata_Security_Handling_Description: None