Identification_Information: Citation: Citation_Information: Originator: NOAA Coastal Services Center (CSC) Originator: U.S. Geological Survey (USGS) Publication_Date: 20041223 Title: Connecticut Coastal ADS40 Digital Imagery Acquisition and Natural Color and Color Infrared Orthophoto Production Geospatial_Data_Presentation_Form: remote-sensing image Description: Abstract: An orthoimage is remotely sensed image data in which displacement of features in the image caused by terrain relief and sensor orientation have been mathematically removed. Orthoimagery combines the image characteristics of a photograph with the geometric qualities of a map. This task consists of two primary components, ADS40 digital image acquisition and natural color and color infrared digital orthophoto production. In addition to the orthophotos a reflective surface digital elevation data set covering the project area was produced. Purpose: These data have been created as a result of the need for having geospatial data immediately available and easily accessible in order to enhance the capability of the NOAA Coastal Services Center (CSC) and the USGS. Supplemental_Information: The bounding coordinates provided within the Spatial Domain section represent a rectangle covering the total area in which the project is located. The actual project boundary located within this area is comprised of areas delimited by areas along the coast of the state of Connecticut. The Coastal Connecticut project area is comprised of approximately 930 square miles. A total of 244 orthos (122 natural color and 122 color infrared) were produced to cover this area. Aerial imagery was collected in panchromatic, Red, Green, Blue and Near Infrared which yielded a natural color and false color infrared version of the completed digital orthophotography. In addition to producing the digital ortho imagery a first surface (reflective surface) elevation data set was produced. Imagery was collected at an approximate altitude of 15,750 feet above mean terrain. The ADS40 digital camera system used in this project incorporates the latest in sensor technology, optics, electronics, data transfer, and storage. The ADS40 imagery is generated from seven parallel sensor lines in the focal plane of a single lens system, three panchromatic (forward, nadir, backward), red, green, and blue lines placed next to each other, and one infrared. Each panchromatic channel consists of two lines, each with 12,000 pixels, staggered (shifted with respect to each other) by 0.5 pixels. The viewing angles and characteristics of the sensor are as follows - - Focal length 62.5mm - Pixel size 6.5mm - PAN 2 arrays 12,000 pixels each - R,G,B and NIR,R,G 12,000 pixels - Backward to nadir stereo angle -14.1 degrees - Near infrared to nadir stereo angle -2.05 degrees - Dynamic Range of CCD - 12-bits for all arrays For this dataset, the natural color and color infrared orthoimages were produced at 0.50-meter pixel resolution. Each digital orthorectified quarter quad provides imagery for a nominal 3.75 by 3.75 minute area corresponding to the USGS quarter quad boundaries. The projected coordinate system is UTM (Zone 18) with a NAD83 datum. The naming convention is based on the National Grid. Deliverables include - - 24-Bit Natural Color in GeoTIFF format - 24-Bit False Color Infrared in GeoTIFF format - Reflective surface digital elevation data set in .flt format Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: 20040920 Ending_Date: 20040922 Currentness_Reference: Ground Condition Status: Progress: Complete Maintenance_and_Update_Frequency: Unknown Spatial_Domain: Bounding_Coordinates: West_Bounding_Coordinate: -073.811097 East_Bounding_Coordinate: -071.755583 North_Bounding_Coordinate: +41.658672 South_Bounding_Coordinate: +40.911606 Keywords: Theme: Theme_Keyword_Thesaurus: None Theme_Keyword: rectified imagery Theme_Keyword: rectified image Theme_Keyword: orthophoto Theme_Keyword: Digital Orthophoto Quarter Quad (DOQQ) Theme_Keyword: image map Theme_Keyword: Natural Color DOQQ Theme_Keyword: Color Infrared DOQQ Theme_Keyword: False Color Infrared DOQQ Place: Place_Keyword_Thesaurus: Geographic Names Information System Place_Keyword: United States of America Place_Keyword: Connecticut Place_Keyword: CT Place_Keyword: US Access_Constraints: None Use_Constraints: None Data_Set_Credit: EarthData International, LLC Native_Data_Set_Environment: Leica ADS40 Digital Camera System ISTAR Digital Image Processing Software Z/I Imaging Orthopro 4.0 Windows NT/2000 Systems Data_Quality_Information: Attribute_Accuracy: Attribute_Accuracy_Report: The digital imagery for each acquisition sortie is differentially rectified to produce orthophotography for the Red, Green, and Blue and near infrared channels at a resolution of 0.50-meter per pixel. The orthophoto mosaics are inspected for accuracy issues that fall in the following categories - - Aerotriangulation related - DSM related Accuracy issues will be investigated through review an correction of the DSM or triangulation adjustment. Once the imagery has passed quality control review, final radiometric adjustments are performed to create a uniform overall appearance. Logical_Consistency_Report: Compliance with the accuracy standard was ensured by the placement of photo identifiable ground control points and the collection of airborne GPS data. Using several tools that are part of the ISTAR workflow, a digital surface model (DSM) was correlated at a post spacing of 2 meters depending on terrain and land cover. The ISTAR correlation algorithm computes the X,Y,Z value for each DSM post utilizing every stereo angle that is available. A series of DSM files were created for each acquisition block, one for each stereo look angle. A mosaic was then created from the separate DSM files where the best vertical value for each posting was selected from all look anglescompared against the aerotriangulation adjustment which is incorporated into the mosaic. EarthData then edited the surface to the level required to support the orthophoto production. An RMS value was calculated based on the imagery utilized in the production of the tile by comparing the AT X and Y coordinates. This value represents an estimate of the accuracy of the horizontal coordinate measurements in the tile expressed in meters. Completeness_Report: Compliance with the accuracy standard was ensured by the placement of photo identifiable ground control points and the collection of airborne GPS data. Positional_Accuracy: Horizontal_Positional_Accuracy: Horizontal_Positional_Accuracy_Report: The horizontal accuracy of the orthorectified images is mainly determined by the accuracy of the aerotriangulation and digital surface model (DSM). For each rectified image (lift), an RMSE value for all of the standard errors of the tie/pass/control points located in that image (lift) and computed by the aerotriangulation solution was calculated. The DSM accuracy assessment was achieved by comparing the aerotriangulation-derived elevation with the elevation of the DSM. In addition, visual examination was employed to assess all tiles and its relative edge match. All results were examined for consistency and its compliance with the NMAS accuracy standard. Quantitative_Horizontal_Positional_Accuracy_Assessment: Horizontal_Positional_Accuracy_Value: 0.273256 Horizontal_Positional_Accuracy_Explanation: Accuracy assessment determined by evaluating the horizontal accuracy obtained during the aerotriangulation process for each lift. Vertical_Positional_Accuracy: Vertical_Positional_Accuracy_Report: CheckDEM is a program designed to compare a list of controls against DEM file(s) and therefore to check the accuracy of the DEM file(s). For each control point, first, the program selects all the DEM points that fall into a given radius from the position of the control point. Second, the program calculates a weighted average of the DEM points to interpolate an elevation at the position of the control point. And last, the program computes the difference between the elevation of the control point and the interpolated elevation. After all the control points have been checked, the program computes several statistics on the differences between controls and interpolated DEM elevations. The statistics include RMSE, Standard Deviation, Minimum Difference, Maximum Difference, and Mean Difference. In the output report, the program prints out elevation differences for every control points and the statistics. Raw elevation measurements have been determined to be vertically accurate to within 0.328 meters. Lineage: Source_Information: Source_Citation: Citation_Information: Originator: Terrasurv Inc. Publication_Date: 20041223 Publication_Time: Unknown Title: Ground Control Survey of Coastal Connecticut Geospatial_Data_Presentation_Form: model Type_of_Source_Media: digital Source_Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: 20040927 Ending_Date: 20040928 Source_Currentness_Reference: Ground Condition Source_Citation_Abbreviation: GPS ground control Source_Contribution: Terrasurv Inc. established ground control to support the aerotriangulation process. A total of 16 points were surveyed to support the AT process. Source_Information: Source_Citation: Citation_Information: Originator: EarthData International Publication_Date: 20041223 Publication_Time: Unknown Title: Coastal Connecticut Digital Surface Model Geospatial_Data_Presentation_Form: model Type_of_Source_Media: digital Source_Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: 20041223 Source_Currentness_Reference: Publication Date Source_Citation_Abbreviation: digital surface model Source_Contribution: Used to provide ground elevations for the orthorectification process. Source_Information: Source_Citation: Citation_Information: Originator: EarthData International, LLC Publication_Date: 20041223 Publication_Time: Unknown Title: ADS40 Digital Imagery Geospatial_Data_Presentation_Form: remote-sensing image Type_of_Source_Media: digital Source_Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: 20040920 Ending_Date: 20040922 Source_Currentness_Reference: Ground Condition Source_Citation_Abbreviation: imagery Source_Contribution: The digital imagery mission was composed of a total of 2 lifts. Imagery was obtained at an altitude of 15,750 feet above mean terrain. The mission was flown with a Leica ADS40 digital camera with ABGPS and IMU. Imagery was acquired on the following dates - Lift Date 26404B 09/20/2004 26604A 09/22/2004 Process_Step: Process_Description: Source Imagery - ADS40 Digital Camera Imagery. Control - Airborne GPS/IMU supplemented with photo identifiable field control Aerotriangulation - ISTAR software package Elevation Model - ISTAR software package Radiometric Balancing - ISTAR software package and COTS Software (PhotoShop). Orthorectification - ISTAR software package. Mosaic - ISTAR software package and Z/I Imaging OrthoPro software package. The following section describes the ISTAR digital image production sequence. This is a mature, stable workflow and incorporates all production components into an integrated series of tools to accomplish photogrammetric mensuration, aerotriangulation, elevation model development, ortho production and finishing. Production processes are fully documented in accordance with ISO9001 mandates. The following is a step-by-step description of the ISTAR workflow to develop digital orthophoto quarter quads to Step 1 The unprocessed ADS40 data and accompanying GPS and IMU data for one or more sorties was downloaded from the portable hard disks and checked to verify that no files were corrupted and that all data could be downloaded. Digital aerial imagery that was used for this project includes the Red, Green, Blue, Near Infrared channels as well as the S1 pan, S2 pan and nadir green channels. Sample segments of the imagery were inspected in an uncorrected state to verify the integrity of each data sortie. Step 2 The GPS/IMU parameters for each sortie were optimized using the ground control points and the error calibration map. The horizontal and vertical positions of all ground control points in the block were observed in each channel (R,G,B, IR, R, G, S1 Pan, S2 Pan). Step 3 Aerotriangulation was accomplished using the CLB tool that is a component of the ISTAR process. The ground control, GPS and IMU information were ingested and tie points between strips were identified. Normally, only 3 tie points are needed between adjacent flight lines. Step 4 CLB produces a bundle adjustment for each data sortie. The results of the adjustment were verified through the development of a sub-sampled panchromatic mosaic for the data sortie. The mosaic was corrected using the aerotriangulation points only. This mosaic was inspected by the photogrammetric technician to identify any gross errors in the adjustment as well as the identification of any voids or image quality problems. Step 5 Using several tools that are part of the ISTAR workflow, a digital surface model (DSM) is correlated at a post spacing of 2 meters depending on terrain and land cover. The ISTAR correlation algorithm computes the X,Y,Z value for each DSM post utilizing every stereo angle that is available. A series of DSM files are created for acquisition block, one for each stereo look angle. A mosaic is then created from the separate DSM files where the best vertical value for each posting is selected from all look angles compared against the aerotriangulation adjustment which is incorporated into the mosaic. EarthData will then edit the surface to the level required to support the orthophoto production. Step 6 The digital imagery for each acquisition sortie was differentially rectified to produce digital orthophoto mosaics in natural color and false color infrared renditions at a resolution of 0.50-meter per pixel. The orthophoto mosaics were inspected for accuracy issues that fall in the following categories - - Aerotriangulation related - DSM related Accuracy issues were investigated through review and correction of the DEM or triangulation adjustment. Once the imagery passed quality control review, final radiometric adjustments were performed to create a uniform overall appearance. The final DOQQ tiles were organized for nominal 3.75 by 3.75 minute areas corresponding to the USGS quarter quad boundaries and were clipped out with the specified overage of a minimum of 30 meters beyond the quarter quad boundaries. Imagery was output in the folowing formats - 24-bit natural color GeoTIFF images 24-bit false color infrared GeoTIFF images Step 7 The completed digital orthophotos were checked for image quality. Minor artifacts were corrected using Adobe Photoshop in an interactive editing session. Digital files were assigned final names based on the National Grid. Step 8 Project level metadata describing the orthophoto production process was developed to support the task. Source_Used_Citation_Abbreviation: imagery, digital surface model, GPS ground control Process_Date: 20041223 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: 0.9996 Longitude_of_Central_Meridian: -075.000000 Latitude_of_Projection_Origin: +00.000000 False_Easting: 500000.0 False_Northing: 0.0 Planar_Coordinate_Information: Planar_Coordinate_Encoding_Method: row and column Coordinate_Representation: Abscissa_Resolution: 0.50 Ordinate_Resolution: 0.50 Planar_Distance_Units: Meters Geodetic_Model: Horizontal_Datum_Name: North American Datum of 1983 Ellipsoid_Name: Geodetic Reference System 80 Semi-major_Axis: 6378137 Denominator_of_Flattening_Ratio: 298.2572221 Distribution_Information: Distributor: Contact_Information: Contact_Organization_Primary: Contact_Organization: NOAA Coastal Services Center Contact_Position: Clearinghouse Manager Contact_Address: Address_Type: mailing address Address: 2234 Hobson Avenue City: Charleston State_or_Province: SC Postal_Code: 29405-2413 Country: US Contact_Voice_Telephone: 1-843-740-1227 Contact_Electronic_Mail_Address: custserv@usgs.gov Hours_of_Service: Monday - Friday, 8:00 AM - 5:00 PM (Eastern Time) Distribution_Liability: Users must assume responsibility to determine the usability of these data. Metadata_Reference_Information: Metadata_Date: 20041223 Metadata_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: NOAA Coastal Services Center Contact_Address: Address_Type: mailing and physical address Address: 2234 South Hobson Avenue City: Charleston State_or_Province: SC Postal_Code: 29405 Country: US Contact_Voice_Telephone: 1-843-740-1227 Hours_of_Service: Monday - Friday, 8:00AM - 5:00PM (Eastern Time) Metadata_Standard_Name: FGDC Content Standard for Digital Geospatial Metadata Metadata_Standard_Version: FGDC-STD-001-1998