National Spatial Data Infrastructure

USGS Geospatial Data Clearinghouse
National Mapping and Remotely Sensed Data


Digital Orthophoto Quadrangles (DOQ)

Digital Orthophoto Quadrangles (DOQ) 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). Plans are for national coverage. This is a data-set level implementation of the Federal Geographic Data Committee's Content Standards for Digital Geospatial Metadata.

Information about county and individual DOQ records can be obtained from the EROS Data Center.


Table of Contents


Identification Information

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: -124.7333
      East_Bounding_Coordinate: -067.9500
      North_Bounding_Coordinate: 49.3833
      South_Bounding_Coordinate: 24.5333
  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

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

Spatial_Data_Organization_Information:
  Direct_Spatial_Reference_Method: raster
  Raster_Object_Information:
    Raster_Object_Type: Pixel


Spatial Reference Information

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

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:
      URL: http://edc.usgs.gov/glis/hyper/guide/usgs_doq


      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:
      URL: ftp://mapping.usgs.gov/pub/ti/DOQ/


Distribution Information

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:


          URL: http://mapping.usgs.gov/esic/esic_index.html


        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:


        URL: http://mapping.usgs.gov/esic/esic_index.html
 
  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:


      URL: http://edc.usgs.gov/glis/hyper/order_info/prices#DOQ_QQUAD
 
  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:


      URL: http://edc.usgs.gov/glis/hyper/order_info/prices#DOQ_COUNTY


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


      URL: http://edc.usgs.gov/webglis


Metadata Reference Information

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: 19940608
  Metadata_Security_Information:
    Metadata_Security_Classification_System: None
    Metadata_Security_Classification: Unclassified
    Metadata_Security_Handling_Description: None

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Last modified: 6 April 1998