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1974 Digital Orthophoto Mosaic - 1:20,000-Scale - Strafford County, New Hampshire

1974 Digital Orthophoto Mosaic - 1:20,000-Scale - Strafford County, New Hampshire

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Metadata:


Identification_Information:
Citation:
Citation_Information:
Originator: Complex Systems Research Center, University of New Hampshire
Publication_Date: 200401
Title:
1974 Digital Orthophoto Mosaic - 1:20,000-Scale - Strafford County, New Hampshire
Edition: One
Geospatial_Data_Presentation_Form: remote-sensing image
Publication_Information:
Publication_Place: Durham, New Hampshire
Publisher: Complex Systems Research Center, University of New Hampshire
Other_Citation_Details: None
Online_Linkage:
<URL:http://www.granit.sr.unh.edu/cgi-bin/nhsearch?dset=74dom/74dom017>
Larger_Work_Citation:
Citation_Information:
Originator: Complex Systems Research Center, University of New Hampshire
Publication_Date: 19860101
Title: NH GRANIT Database
Publication_Information:
Publication_Place: Durham, New Hampshire
Publisher: Complex Systems Research Center, University of New Hampshire
Online_Linkage: <URL:http://www.granit.sr.unh.edu>
Description:
Abstract:
This data set is a countywide mosaic of 1:20,000-scale, black & white aerial photos. It was developed by scanning and orthorectifying 282 individual photographs, and combining a subset of the resulting digital images into the mosaic. The final orthophoto mosaic combines the image characteristics of the source photographs with the geometric qualities of a map.

In addition to the hardcopy photos, the primary data sources used in the photo orthorectification included 1998 1:12,000-scale Digital Orthophoto Quarterquads (DOQS) and 30-meter Digital Elevation Models (DEMs).

The mosaic is provided in IMAGINE (*.img/.ige) format. A MrSID (*.sid) version of the mosaic is also available, but image quality may be poorer due to the compression applied. The 282 individual orthophotos, in .tif format, are also available.

The normal orientation of the 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 radiometric image brightness values are stored as 256 gray levels ranging from 0 to 255.

Note that sections of this metadata record, in particular the Data Quality section, describe the processing performed on the individual photos used to generate the mosaic.

Purpose:
This mosaic of historic orthophotography provides a visual perspective of the landscape in the early 1970's. Due to its geometric qualities, it is useful as a reference layer in a geographic information system, and provides a valuable tool for land use mapping and change analysis.
Supplemental_Information: Data distribution tile: county
Time_Period_of_Content:
Time_Period_Information:
Range_of_Dates/Times:
Beginning_Date: 19740320
Ending_Date: 19741024
Currentness_Reference: ground condition
Status:
Progress: Complete
Maintenance_and_Update_Frequency: None planned
Spatial_Domain:
Bounding_Coordinates:
West_Bounding_Coordinate: -71.261116
East_Bounding_Coordinate: -70.773671
North_Bounding_Coordinate: 43.589150
South_Bounding_Coordinate: 43.050544
Keywords:
Theme:
Theme_Keyword_Thesaurus: None
Theme_Keyword: Digital orthophoto
Theme_Keyword: Digital image map
Theme_Keyword: Aerial photograph
Theme_Keyword: Rectified photograph
Theme_Keyword: Rectified image
Theme_Keyword: Orthophoto
Theme_Keyword: Historic
Place:
Place_Keyword_Thesaurus: None
Place_Keyword: United States
Place_Keyword: Northeast
Place_Keyword: New England
Place_Keyword: New Hampshire
Place_Keyword: Strafford County
Temporal:
Temporal_Keyword_Thesaurus: None
Temporal_Keyword: 1974
Temporal_Keyword: 74
Access_Constraints:
Acknowledgement of GRANIT is appreciated in products derived from these data.
Use_Constraints: Not for legal use
Point_of_Contact:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization: Complex Systems Research Center, University of New Hampshire
Contact_Person: GRANIT Database Manager
Contact_Position: GRANIT Database Manager
Contact_Address:
Address_Type: mailing and physical address
Address: Morse Hall, University of New Hampshire
City: Durham
State_or_Province: NH
Postal_Code: 03824
Country: US
Contact_Voice_Telephone: 603-862-1792
Contact_Facsimile_Telephone: 603-862-0188
Contact_Electronic_Mail_Address: granit@unh.edu
Hours_of_Service: 8:30AM-5PM, EST
Browse_Graphic:
Browse_Graphic_File_Name:
<www.granit.sr.unh.edu/cgi-bin/load_file?PATH=/data/database/d-webdata/74dom/browse.gif>
Browse_Graphic_File_Description: gif image file
Browse_Graphic_File_Type: GIF
Data_Set_Credit: GRANIT database
Native_Data_Set_Environment: IMAGINE format


Data_Quality_Information:

Attribute_Accuracy:
Attribute_Accuracy_Report:
During scanning, the paper positive image brightness and contrast values were collected with a minimum of image quality manipulation. However the scanning process may have changed some of the source brightness values. Once the photography was in digital format, limited brightness and contrast manipulation was performed to improve image quality.

Image brightness and contrast values may also deviate from the brightness values of the original imagery due to image value interpolation during the rectification processes. Radiometry of the rectified imagery was verified by visual inspection of the digital orthophoto with the original unrectified image.

Slight systematic radiometric differences can be detected between adjacent orthophoto 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 orthophoto file coverages.

Logical_Consistency_Report:
All orthophoto imagery was visually inspected for completeness to ensure that no gaps or image misplacement occurred in the image mosaic area.
Completeness_Report:
All orthophotos are cloud free within the image area.

Source photography may be leaf-on or leaf-off in deciduous vegetation regions, depending on the acquisition date of the original imagery.

The countywide product was derived by mosaicking every second image from the complete collection of orthophotos. Due to standard overlap areas in the source photography, this was sufficient to ensure complete, seamless coverage of the county while avoiding the incorporation of excess data.

Positional_Accuracy:
Horizontal_Positional_Accuracy:
Horizontal_Positional_Accuracy_Report:
The horizontal accuracy of each input orthophoto was expressed as an estimated root mean square error (RMSE). The maximum RMSE for all orthophotos used to compile the mosaic was < 1.

Additionally, visual inspection of the countywide mosaic was performed to compare the planimetric (X and Y) coordinates of selected points with the coordinates of the same points as determined from the reference orthophotos.

Lineage:
Source_Information:
Source_Citation:
Citation_Information:
Originator: USDA-APFO
Publication_Date: 1974
Title: 74photo(roll#)-(photo#)
Publication_Information:
Publication_Place: Salt Lake City, UT
Publisher: USDA-APFO
Online_Linkage: N/A
Source_Scale_Denominator: 18000
Type_of_Source_Media: Paper positives
Source_Time_Period_of_Content:
Time_Period_Information:
Range_of_Dates/Times:
Beginning_Date: 19740320
Ending_Date: 19741024
Source_Currentness_Reference: ground condition
Source_Citation_Abbreviation: PHOTO1
Source_Contribution:
Panchromatic NAPP or NAPP-like photographs provided the primary source for the countywide mosaic.
Source_Information:
Source_Citation:
Citation_Information:
Originator: Complex Systems Research Center, University of New Hampshire
Publication_Date: 19990301
Title: Digital Elevation Model
Publication_Information:
Publication_Place: Durham, New Hampshire
Publisher: Complex Systems Research Center, University of New Hampshire
Online_Linkage: URL:<http://www.granit.sr.unh.edu>
Source_Scale_Denominator: 24000
Type_of_Source_Media: Digital file
Source_Time_Period_of_Content:
Time_Period_Information:
Range_of_Dates/Times:
Beginning_Date: 19790701
Ending_Date: present
Source_Currentness_Reference: publication date
Source_Citation_Abbreviation: DEM2
Source_Contribution:
Provided the basic vertical control necessary to perform the orthorectification.
Source_Information:
Source_Citation:
Citation_Information:
Originator: US Geological Survey
Publication_Date: 1998
Title: Digital Orthophoto Quarterquads (98doq(tile#))
Geospatial_Data_Presentation_Form: remote-sensing image
Publication_Information:
Publication_Place: Reston, VA
Publisher: US Geological Survey
Source_Scale_Denominator: 12000
Type_of_Source_Media: Digital File
Source_Time_Period_of_Content:
Time_Period_Information:
Single_Date/Time:
Calendar_Date: 19980428
Source_Currentness_Reference: ground condition
Source_Citation_Abbreviation: DOQ3
Source_Contribution:
Horizontal control used to establish positions for reference and correlation purposes.
Process_Step:
Process_Description:
The source photos (PHOTO1) were converted to digital raster image files (*.tif format) by scanning the paper positives with a Microtek Scanmaker 9800XL. A scanning resolution of 600 dpi was used in the process, which converted the photographic image densities to gray scale values ranging from 0 to 255 (for black and white photographs). The resulting raster image files were degraded to 400 dpi using Adobe Photoshop to reduce file size. Autoleveling of the images was performed to standardize gray scale values as much as possible across all images and to improve general image quality.

Imagine (v8.6) ORTHOBASE was then used to generate orthophotos from the scanned images. In addition to the images, the following inputs were required: a user parameter file (or "block" file) to control the rectification process, a digital elevation model (DEM2) gridded to user specified bounds (with associated projection, zone, datum and X-Y units), scanned digital image reference files (DOQ3) covering the project area (also with associated projection, zone, datum and X-Y units), ground X-Y-Z point values and their conjugate photo coordinates in the camera coordinate system, calculated tie point values and their conjugate photo coordinates in the camera coordinate system and measurements of the fiducial marks in the digitized images.

Typically, a camera calibration report provides data on the focal length of the camera and the distances in millimeters from the camera's optical center to the camera's 4 fiducial marks. These marks define the frame of reference for spatial measurements made from the photograph. The report was obtain from the USDA-APFO office and the information there in was enter into IMAGINE.

Ground control points (GCP's) were acquired by comparing positions visible in both the reference files (DOQ3) and the scanned digital image files. The standard number of GCP's per image was between 10 and 25, and placement was distributed throughout each scanned digital image file. GCP's were measured from the reference files in NH State Plane feet, NAD83. The conjugate positions of the GCP's on the scanned images were measured and recorded in camera coordinates.

In addition to collecting horizontal control (X-Y values) from the reference files (DOQ3), DEM2 was used to collect a corresponding Z value for each GCP. This Z-value aided in minimizing distortion caused by topographic variation across the images.

Tie point values were generated by the software based on feature commonality in the overlap/sidelap areas between multiple images. These points provided additional control during the orthorectification process.

Based on the GCP's and tie points, RMSE's measuring the approximate "fit" of the image transformation were calculated and reviewed. Points associated with values in excess of 1 were relocated or rejected. With the final set of horizontal and vertical control values, each image was orthorectified.

Quality control was conducted by comparing each newly rectified image to adjacent newly rectified images to ensure proper overlay of common features. The digital reference file (DOQ3) was also overlaid on the newly rectified images to ensure proper transfer of coordinates. Once each image passed quality control, the edges were clipped to extract just the core area of the image.

Imagine was then used to generate the countywide mosaic. Essentially, every other photo was utilized, since that provided complete coverage of the area while avoiding the processing of excess data. The resulting file is an Imagine (.img/.ige) file.

Source_Used_Citation_Abbreviation: PHOTO1
Source_Used_Citation_Abbreviation: DEM2
Source_Used_Citation_Abbreviation: DOQ3
Process_Date: 200309
Process_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Organization: Complex Systems Research Center
Contact_Person: GRANIT Database Manager
Contact_Position: GRANIT Database Manager
Contact_Address:
Address_Type: mailing and physical address
Address: Morse Hall, University of New Hampshire
City: Durham
State_or_Province: NH
Postal_Code: 03824
Country: US
Contact_Voice_Telephone: 603-862-1792
Contact_Facsimile_Telephone: 603-862-0188
Contact_Electronic_Mail_Address: granit@unh.edu
Hours_of_Service: 8:30AM-5PM, EST


Spatial_Data_Organization_Information:

Direct_Spatial_Reference_Method: Raster
Raster_Object_Information:
Raster_Object_Type: Pixel
Row_Count: 65111
Column_Count: 42736
Vertical_Count: 1


Spatial_Reference_Information:

Horizontal_Coordinate_System_Definition:
Planar:
Grid_Coordinate_System:
Grid_Coordinate_System_Name: State Plane Coordinate System 1983
State_Plane_Coordinate_System:
SPCS_Zone_Identifier: New Hampshire
Transverse_Mercator:
Scale_Factor_at_Central_Meridian: 0.999967
Longitude_of_Central_Meridian: -71.66666
Latitude_of_Projection_Origin: 42.500000
False_Easting: 984250.000000
False_Northing: 0.000000
Planar_Coordinate_Information:
Planar_Coordinate_Encoding_Method: Row and column
Coordinate_Representation:
Abscissa_Resolution: 3.000000
Ordinate_Resolution: 3.000000
Planar_Distance_Units: survey feet
Geodetic_Model:
Horizontal_Datum_Name: North American Datum of 1983
Ellipsoid_Name: Geodetic Reference System 80
Semi-major_Axis: 6378137.000000
Denominator_of_Flattening_Ratio: 298.257222


Entity_and_Attribute_Information:

Overview_Description:
Entity_and_Attribute_Overview:
For orthophotos from panchromatic sources, 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 represented as a shade of gray varying from black to white.
Entity_and_Attribute_Detail_Citation:
None


Distribution_Information:
Distributor:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization: Complex Systems Research Center
Contact_Person: GRANIT Database Manager
Contact_Position: GRANIT Database Manager
Contact_Address:
Address_Type: mailing and physical address
Address: Morse Hall, University of New Hampshire
City: Durham
State_or_Province: NH
Postal_Code: 03824
Country: US
Contact_Voice_Telephone: 603-862-1792
Contact_Facsimile_Telephone: 603-862-0188
Contact_Electronic_Mail_Address: granit@unh.edu
Hours_of_Service: 8:30AM-5PM. EST
Resource_Description: Downloadable Data
Distribution_Liability:
Digital data in NH GRANIT represent the efforts of the contributing agencies to record information from the cited source materials. Complex Systems Research Center, under contract to the NH Office of State Planning, and in consultation with cooperating agencies, maintains a continuing program to identify and correct errors in these data. OSP, CSRC, and the cooperating agencies make no claim as to the validity or reliability or to any implied uses of these data.
Standard_Order_Process:
Digital_Form:
Digital_Transfer_Information:
Format_Name: Imagine (.img/.ige)
Transfer_Size: 2.7 G
Digital_Transfer_Option:
Online_Option:
Computer_Contact_Information:
Network_Address:
Network_Resource_Name: <URL:http://www.granit.sr.unh.edu>
Fees:
No charge when downloaded from the Internet. Cost of reproduction for provision on CD/ROM, DVD, or other media.
Ordering_Instructions:
Email GRANIT (granit@unh.edu) or order from web site (www.granit.sr.unh.edu).
Turnaround: Two weeks.
Technical_Prerequisites: None

Metadata_Reference_Information:
Metadata_Date: 20030113
Metadata_Contact:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization: Complex Systems Research Center, University of New Hampshire
Contact_Person: GRANIT Database Manager
Contact_Position: GRANIT Database Manager
Contact_Address:
Address_Type: mailing and physical address
Address: Morse Hall, University of New Hampshire
City: Durham
State_or_Province: NH
Postal_Code: 03824
Country: US
Contact_Voice_Telephone: 603-862-1792
Contact_Facsimile_Telephone: 603-862-0188
Contact_Electronic_Mail_Address: granit@unh.edu
Hours_of_Service: 8:30AM-5PM, EST
Metadata_Standard_Name: FGDC Content Standards for Digital Geospatial Metadata
Metadata_Standard_Version: FGDC-STD-001-1998
Metadata_Time_Convention: local time


Generated by mp version 2.8.13 on Thu Dec 13 10:07:03 2007
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