| IMAGES.GIS.COLOR_AERIALS_2005 | |
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Data format: SDE Raster Dataset File or table name: IMAGES.GIS.COLOR_AERIALS_2005 Coordinate system: Transverse Mercator Theme keywords: Digital Orthos, Imagery, Aerial photography, Aerotriangulation, ADS40, DSM, Digital Surface Model, DEM, Digital Elevation Model, orthoimagery, Aerial Acquisition |
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Abstract:
This metadata record describes the acquisition and
production of natural color and color infrared digital ground orthoimagery
covering Lee County, Florida and the Babcock Ranch Property. The orthos
were produced at a scale of 1 to 1, 2400 with a 6 inch pixel
resolution for the project area. An updated DEM in ASCII format
and Mylars plotted at 1 to 2,400 were provided |
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Metadata elements shown with blue text are defined in the Federal Geographic Data Committee's (FGDC) Content Standard for Digital Geospatial Metadata (CSDGM). Elements shown with green text are defined in the ESRI Profile of the CSDGM. Elements shown with a green asterisk (*) will be automatically updated by ArcCatalog. ArcCatalog adds hints indicating which FGDC elements are mandatory; these are shown with gray text.
This metadata record describes the acquisition and production of natural color and color infrared digital ground orthoimagery covering Lee County, Florida and the Babcock Ranch Property. The orthos were produced at a scale of 1 to 1, 2400 with a 6 inch pixel resolution for the project area. An updated DEM in ASCII format and Mylars plotted at 1 to 2,400 were provided
The acquisition, production, and delivery of natural color and color infrared digital orthoimagery covering Lee County, Florida The imagery will be used for environmental planning, resource inventory, and GIS development.
Ground Condition
None
7320 Executive Way
This data has been produced to be fully compliant with the National Map Accuracy Standards (NMAS) for mapping at a scale of 1 to 1,200.
Compliance with the accuracy standard was ensured by the collection of photo identifiable GPS ground control after the acquisition of aerial imagery. The following checks were performed. 1. The ground control and airborne GPS data stream were validated through a fully analytical bundle aerotriangulation adjustment. The RMSE is less than 1, 10,000th of the flying height. 2. The DSM (DEM) data was checked against the project control. The technician visited and confirmed the accuracy of the points during initial processing 3. Digital orthophotography was validated through an inspection of edge matching and visual inspection for image quality.
The following methods are used to assure imagery accuracy. 1. Use of IMU (inertial measurment unit) and ground control network utilizing GPS techniques. 2. Use of airborne GPS (global positioning system) in conjunction with the acquisition of imagery. The following software is used for validation of the imagery and surface modeling. 1. Aerotriangulation - ISTAR 2. DSM and DEM data - ISTAR 3. Digital Orthophotography - ISTAR, OrthoPro, and Photoshop. 4. Bentley - MicroStation 5. ISTAR 6. ESRI - ArcGIS 7. EarthData proprietary software 8. Adobe - Photoshop
This data has been produced to be fully compliant with the National Map Accuracy Standards (NMAS) for mapping at a scale of 1 to 1,200 with a 6 inch pixel resolution.
The aerial imagery acquisition for Lee County was flown to support the creation of digital orthophotography with a 6 inch pixel resolution. The imagery was acquired in 3 lift consisting of 96 lines running East-West. The imagery was flown at 4,750 feet AMT. Imagery was flown with a 30% overlap between flight lines. All imagery was collected using the Leica ADS40 digital pushbroom sensor.
TerraSurv, Inc, under contract to EarthData International successfully established ground control for the Lee County project area. A total of 15 ground control points were acquired using GPS for both vertical and horizontal coordinate values.
EarthData utilized an ISTAR workflow for processing the Aerotriangulation for the orthoimagery covering Lee County, FL. The airborne GPS data was processed and integrated with the inertial measurement unit (IMU). The resulting imagery and control were imported into the ISTAR system for use in the aerotriangulation. The ADS40 imagery was downloaded onto the EarthData server and brought over to the UNIX based ISTAR system. The ground control was used in conjunction with the processed airborne global positioning system (ABGPS) results for the aerotriangulation. The ground control points were read in all available imagery and tie points between flight lines were selected. A fully analytical bundle adjustment was run. The properly formatted ISTAR results were used for subsequent processing. All final results were output into an AT report which is being delivered with the final orthos.
7320 Executive Way
ISTAR was used in the processing of the DEM for orthorectification of the imagery covering the Lee County, FL project area. The existing DEM surface was imported into the ISTAR system. In areas of change the a new surface was generated. The ISTAR digital surface modeling is based on an auto correlated pixel-matching system within the ISTAR software. The auto correlated digital surface model (DSM) surface represents the initial surface model. The following is the process used. 1. Using the DSM ISTAR data set created, the technician performed a visual inspection of the data to verify that the flight lines met correctly. The technician also verified that there were no voids, and that the data covered the project limits. The technician then selected a series of areas from the dataset and inspected them where adjacent flight lines met. 2. This DSM surface is used in the rectification of the orthoimagery. This process created an update surface from the 2005 imagery. The data was exported to ASCII format.
7320 Executive Way
The digital orthophotography is comprised of natural color and color infrared 6 inch pixel resolution ground orthos for Lee County, Fl. The ISTAR process was used in the generation of the orthoimagery covering Lee County, FL. The initial radiometric adjustments were performed on the imagery for each flight line attempting to reach the best possible histogram. The rectification process was then run using the processed DSM surface and the radiometrically balanced imagery on each flight line. The quicklook (reduced resolution rectification) of each flight line exported out of ISTAR. A second set of radiometric adjustments were made using EarthData proprietary tools. The radiometrically balanced imagery was then re-imported into the ISTAR system and the histogram from the quicklook was applied to the full resolution imagery. Mosaic lines were placed, joining the ADS40 imagery strips. In initial QA/QC was performed by the technician to ensure that the mosaic lines were appropriately placed and that there was appropriate imagery coverage. The final imagery data set is removed from the ISTAR environment in a process called "packaging" where the individual tiles are created. All data processing in the ISTAR system is performed in UTM meters; it is during packaging that final datum and projection are defined. The created tiles are reviewed again for anomalies and interactive radiometric adjustment applied where needed. QA/QC was performed looking for anomalies, smears and other indications of problems within the digital Orthophoto creation process, interactive radiometric adjustment applied where needed. Two additional radiometric adjustments are applied to the completed orthos in Adobe Photoshop. The first is a sharpening mask filter; this filter is used to help increase sharpness of a digital image. The basis for this filter is to locate pixels that differ in value from surrounding pixels by the threshold specified. It then increases the pixels' contrast by the value identified. For neighboring pixels specified by the threshold, the lighter pixels get even lighter and the darker pixels get even darker based on the specified amount. The changes made maintained the integrity of the original histogram curve. The final digital ortho product was GeoTiff All data was delivered on DVDs.One set of black and white Mylars plots at a scale of 1 to 2,400 cut to Township,Section and Range were provided.
7320 Executive Way
Metadata imported.
1500 Monroe Street, 4th Floor
None
7320 Executive Way