Digital Orthophoto Quadrangles

Metadata:

• Identification_Information
• Data_Quality_Information
• Spatial_Data_Organization_Information
• Spatial_Reference_Information
• Entity_and_Attribute_Information
• Distribution_Information
• Metadata
• Metadata_Reference_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:

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.

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:
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:

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: FGDC-STD-001-1998

Metadata_Security_Information:

Metadata_Security_Classification_System: None

Metadata_Security_Classification: Unclassified

Metadata_Security_Handling_Description: None