Digital Orthophoto (DOQQ - quarter-quadrangle) for Pennsylvania


Identification_Information:
Citation:
Citation_Information:
Originator:U.S. Geologic Survey; Pennsylvania Bureau of Topographic and Geologic Survey
Publication_Date:1993
Title:
Digital Orthophoto (DOQQ - quarter-quadrangle) for Pennsylvania
Publication_Information:
Publication_Place:Reston, VA
Publisher:U.S. Geological Survey
Online_Linkage: http://www.pasda.psu.edu/
Larger_Work_Citation:
Citation_Information:
Originator:US Department of Commerce
Publication_Date:1993
Title:
Pennsylvania Digital Orthophotos
Publication_Information:
Publication_Place:Washington D.C.
Publisher:Bureau of the Census
Online_Linkage: http://www.pasda.psu.edu/ftp/doqlist.cgi
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 embedded 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. 
DOQ images are acquired as a part of the USGS' National Aerial Photography Program (NAPP).
Through NAPP imagery for each state is produced on a 7 year cycle.
 These images are the NAPP III cycle which will run from 1997-2001
These DOQQ's are distributed through PASDA as GeoTIFF images as received from USGS.
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:
Single_Date/Time:
Calendar_Date:1993
Currentness_Reference:
ground condition
Status:
Progress:On-going
Maintenance_and_Update_Frequency:Irregular
Spatial_Domain:
Bounding_Coordinates:
West_Bounding_Coordinate:-77
East_Bounding_Coordinate:-76.875
North_Bounding_Coordinate:40
South_Bounding_Coordinate:39.875
Keywords:
Theme:
Theme_Keyword_Thesaurus:ISO 19115 Topic Categories
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:3.75- x 3.75-minute orthophoto
Theme_Keyword:7.5- x 7.5-minute orthophoto
Theme_Keyword:National Aerial Photography Program
Theme_Keyword:NAPP
Theme_Keyword:imageryBaseMapsEarthCover
Place:
Place_Keyword_Thesaurus:none
Place_Keyword:Pennsylvania
Access_Constraints:None
Use_Constraints:
Acknowledgement of the U.S. Geological Survey would be appreciated in products derived from these data.
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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.
Quantitative_Horizontal_Positional_Accuracy_Assessment:
Horizontal_Positional_Accuracy_Value:RMSE
Horizontal_Positional_Accuracy_Explanation:
U.S.Bureau of the Budget, 1947, United States National Map
Accuracy Standard.
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:19920329
Ending_Date:19950406
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:Unknown
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:Unknown
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:Unknown
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:Unknown
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:Unknown
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.
Process_Date:Unknown
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Spatial_Reference_Information:
Horizontal_Coordinate_System_Definition:
Planar:
Grid_Coordinate_System:
Grid_Coordinate_System_Name:Universal Transverse Mercator
Universal_Transverse_Mercator:
UTM_Zone_Number:18
Transverse_Mercator:
Scale_Factor_at_Central_Meridian:0.09996
Longitude_of_Central_Meridian:-123.00
Latitude_of_Projection_Origin:0.0
False_Easting:500000.0
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
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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.pd
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Distribution_Information:
Distributor:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization:Pennsylvania Spatial Data Access (PASDA)
Contact_Address:
Address_Type:mailing address
Address:
Land and Water Building
City:University Park
State_or_Province:PA
Postal_Code:16802
Country:USA
Contact_Voice_Telephone:(814) 865-8792
Contact_Electronic_Mail_Address:pasda@psu.edu
Resource_Description:downloadabledata
Distribution_Liability:
The USER shall indemnify, save harmless, and, if requested, defend those parties involved with the development and distribution of this data, their officers, agents, and employees from and against any suits, claims, or actions for injury, death, or property damage arising out of the use of or any defect in the FILES or any accompanying documentation. Those parties involved with the development and distribution excluded any and all implied warranties, including warranties or merchantability and fitness for a particular purpose and makes no warranty or representation, either express or implied, with respect to the FILES or accompanying documentation, including its quality, performance, merchantability, or fitness for a particular purpose. The FILES and documentation are provided "as is" and the USER assumes the entire risk as to its quality and performance. Those parties involved with the development and distribution of this data will not be liable for any direct, indirect, special, incidental, or consequential damages arising out of the use or inability to use the FILES or any accompanying documentation.
Standard_Order_Process:
Digital_Form:
Digital_Transfer_Information:
Format_Name:Imagery, GeoTIFF
Format_Information_Content:
Each DOQQ distribution file is comprised of the image file, which has .TIF as the filename extension; and a header file, which has .hdr as the filename extension and includes further image specific metadata and a world file with .tfw as the filename extension.
File_Decompression_Technique:zip
Transfer_Size:35-45 MB
Digital_Transfer_Option:
Online_Option:
Computer_Contact_Information:
Network_Address:
Network_Resource_Name: ftp://www.pasda.psu.edu/pub/pasda/doq99
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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 8-mm and 3480 cartridges the costs are: 1 digital product = $40 2 digital products = $60 3 digital products = $80 4 digital products = $100 5 digital products = $120 6 or more = $90 plus $7 per each product over six A $3.50 handling charge is applied to all mail orders.
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 charge is $32 per CD-ROM. A $3.50 handling charge is applied to all mail orders.
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Metadata_Reference_Information:
Metadata_Date:2008
Metadata_Review_Date:20010501
Metadata_Contact:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization:Pennsylvania Spatial Data Access (PASDA)
Contact_Position:Metadata Coordinator
Contact_Address:
Address_Type:mailing address
Address:
115 Land and Water Building
City:University Park
State_or_Province:PA
Postal_Code:16802
Country:USA
Contact_Voice_Telephone:814-865-8792
Contact_Electronic_Mail_Address:pasda@psu.edu
Metadata_Standard_Name:Content Standards for Digital Geospatial Metadata
Metadata_Standard_Version:FGDC-STD-001-1998
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