Coastal Connecticut 2005 Color Infrared Orthophoto is a set of 1:12,000-scale orthorectified imagery. These data were compiled from a set of 1129 individual tide controlled vertical aerial photos taken over six distinct days during June 15 to September 15, 2005. The 2005 Connecticut Coastal Color Infrared Aerial Photography Project which captured these photos covers the geographic extent of Connecticut defined by : * all land areas within one-thousand (1000) feet of Mean High Water (MHW) and within one-thousand (1000) feet of state-regulated tidal wetlands; * an area of at least two-thousand (2000) feet waterward of the immediate shoreline of Long Island Sound in order to clearly depict the interface between the shorelands and coastal waters; * all offshore islands within the territorial borders of the State of Connecticut including Goose Island and Falkner Island (offshore of Branford); Calf Islands and Great Captain Island (offshore of Greenwich); Norwalk Islands (offshore of Norwalk); Thimble Islands (offshore of Branford); Sandy Point (offshore of Stonington); and all islands in the Connecticut part of Fishers Island Sound; and * the main stem of the Connecticut River up to the Massachusetts State line. The individual aerial photos were scanned, orthorectifed, and mosaicked into grid-based system. The geographic extent of each digital orthophoto is equivalent to 3¾ minutes of latitude and longitude, plus a little overlap based on US Geological Survey (USGS) Quarter Quads. Typically USGS Quarter Quads are comprised of four sections per 7½ minute USGS Quadrangle map area - one for the northeast, northwest, southeast, and southwest sections. For this project, since the extent of the area photographed may not cover an entire quarter quad section there are cases where there is either no data for parts of a section or no section at all. Naming conventions follow standard USGS fomat, i.e., Q1234_ne, Q1234_nw, Q1234_se, Q1234_sw, etc. The ground resolution of the imagery is approximately 1 ft per pixel. Data is compiled at 1:12,000 scale. This data is not updated.
A digital orthophoto is a digital image of an aerial photograph in which displacements caused by the camera and the terrain have been removed. It combines the image characteristics of a photograph with the geometric qualities of a map. A digital orthophoto has the same scale throughout and can be used as a map for measuring distances, calculating areas, determining the shape of features, and reading coordinate locations, for example. Digital orthophotos provide the necessary background (base map) layer information to which other spatial data layers are registered or created. The process of creating an orthophoto, orthorectification, corrects the geometry of a aerial photo image so that it appears as though each pixel were acquired from directly overhead. Orthorectification uses elevation data to correct terrain distortion in aerial or satellite imagery. To maximize the quality of the images and their contents, photography for the 2005 Connecticut Coastal Color Infrared Aerial Photography Project conformed to the following environmental conditions: * photos were only taken during times of no/minimal cloud cover when lighting and weather conditions optimized the color infrared film; * solar altitude was more than thirty (30) degrees; * the ground detail was not obscured by flooding; * the foliage (salt marsh vegetation in particular) was fully developed; * seasonal conditions (summer) favored maximum human use/recreation activities (e.g., boats & temporary docks/structures in water, etc.); * photo times were planned within one (1) hour window before or after a predicted low tide based on National Oceanic & Atmospheric Administration (NOAA) predicted tide tables. (In instances where this window caused conflicts with the general restricted hours, tide coordination times superceded that limitation); and * no photography was flown between the hours 1100 and 1300 Eastern Standard Time (EST) to minimize specular reflection. The photos exist as 1:12,000 orthorectified color infrared images. Color infrared photography, often called false color photography because it renders the scene in other than the normal colors seen by the human eye, is widely used for interpretation of natural resources. Atmospheric haze does not interfere with the acquisition of the image, therefore is well suited to aerial photography. Because the film is high speed and subject to degrees of degradation in handling before exposure, the aerial photographs can vary in overall tone. This variability can complicate the interpretation of color tones between photographs, but some general guidelines can be given to aid the inexperienced interpreter. * The red tone of color infrared aerial photographs is almost always associated with live vegetation. Very intense reds indicate vegetation which is growing vigorously and is quite dense. Knowledge of the vigor and density of vegetation is important to the interpretation of the red colors on color infrared aerial photography. * As the vigor and density of vegetation decreases, the tones may change to light reds and pinks. If plant density becomes low enough the faint reds may be overcome by the tones of the soils on which the plants are growing. The ground areas in this case will appear in shades of white, blue, or green depending on the kind of soil and its moisture content. As plant vigor decreases, the vegetation will show as lighter shades of red and pink, various shades of greens, and possible tans. Dead vegetation will often be shades of greens or tans. * Bare soils will appear as shades of white, blue, or green in most agricultural regions. In general, the more moist the soil the darker the shade of that particular soil color. Composition of the soil will affect the color tones shown on the photographs. Dry sand will appear white and, with more moisture, may be very light gray or possibly light tan. Clayey soils will generally be darker in color than sands and tend toward tans and bluegreens. Again, wetter clays will be darker shades of the same tones. Soils high in organic matter, like silts and loams will be even darker in color, and usually in shades of blues and greens. Wet organic soils can be very dark blue or green in the aerial photographs. * Man-made features will show in the tones that relate to the materials they are made of. Asphalt roads, for example, will be dark blue or black, gravel or dirt roads will show as lighter colors, depending on the soil materials involved in their composition, and concrete roads will appear light in tone, assuming clean concrete. The buildings and streets of towns can be considered in a similar manner, their color dependent on the material they are made of. * Water will appear as shades of blue, varying from nearly black to very pale blue. Clear, clean water will appear nearly black. As the amount of sediment increases, the color becomes increasingly lighter blue. Very shallow water will often appear as the material present in the bottom of the stream. For example, a very shallow stream with a sandy bottom will appear white due to the high level of reflection of the sand. * Degraded film will result in photographs which have an overall blue or green cast. When that occurs, the interpretation must consider what that overall cast will do to a "normal" rendition of the scene. (Description and guidelines for color infrared photography taken from the United States Geological Survey Aerial Photo FAQ web page, http://edc.usgs.gov/guides/news/aerialfaq.htmlt#A10)
date of photography
James W. Sewall Co. of Old Town, Maine was contracted by the State of Connecticut to perform the 2005 Connecticut Coastal Color Infrared Aerial Photography Project. All imagery and data products were defined under State of Connecticut contract award number 05PSX0128AA.
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2005 Connecticut Coastal Color Infrared Digital Orthophotography is 1:12,000-scale data. It depicts land use, natural resources, vegetation, and other features and characteristics in the immediate shoreline areas of Connecticut during the summer of 2005. Use this layer as a basemap for depicting coastal features/landscapes, as a source for georeferencing other imagery or data, or to analyze the landscape, features, or activities of the coastal area.
Original photos on aerial photography grade color infrared film. Used to create the digital scans. Final product deliverable.
Digital scans of the original film used during the orthorectification and mosaicking processes and in the creation of the contact prints. Final product deliverable.
Used as triangulation controls during the orthorectification process.
Used to correct aerial photography. Removes image displacements caused by camera tilt and relief of terrain.
Final product deliverable.
ESRI Raster Dataset mosaic of all input rasters delivered.
Aerial Flight: Overview: A set of 1129 individual aerial photos were taken over six distinct days during June 15 to September 15, 2005. The geographic extent of the photography includes: * all land areas within one-thousand (1000) feet of Mean High Water (MHW) and within one-thousand (1000) feet of state-regulated tidal wetlands; * an area of at least two-thousand (2000) feet waterward of the immediate shoreline of Long Island Sound in order to clearly depict the interface between the shorelands and coastal waters; * all offshore islands within the territorial borders of the State of Connecticut including Goose Island and Falkner Island (offshore of Branford); Calf Islands and Great Captain Island (offshore of Greenwich); Norwalk Islands (offshore of Norwalk); Thimble Islands (offshore of Branford); Sandy Point (offshore of Stonington); and all islands in the Connecticut part of Fishers Island Sound; and * the main stem of the Connecticut River up to the Massachusetts State line. Project Specifications: * Scale - Flown at altitudes suitable to produce photography at a scale of 1:12000 (1inch = 1000 ft) (Recommended tolerance of +/- 5%) * Timing - Photography was only taken during times of no/minimal cloud cover when lighting and weather conditions were such that color infrared film suited for the desired use of the imagery were optimized; No photography was flown between the hours 1100 and 1300 Eastern Standard Time (EST) to minimize specular reflection. Seasonal conditions (summer) favored maximum human use/recreation activities (e.g., boats & temporary docks/structures in water, etc.) * Solar Angle - Solar altitude was more than thirty (30) degrees; * Ground Conditions - Ground detail was not obscured by flooding; Foliage (salt marsh vegetation in particular) was fully developed (i.e., leaf-on conditions) * Tide Control - All photography was taken within a one (1) hour window before or after low tide based on NOAA predicted tide tables. (In instances where this window caused conflicts with the general restricted hours, tide coordination times superceded that limitation.) * Sidelap - ~30% (Recommended Tolerance of 25% +/- 10%) * Endlap - ~60% (Recommended Tolerance between 57 - 62%) * Crabbing - No more than 5 degrees for two or more consecutive photos * Tilt - Not to exceed 4 degrees for any photo, 2 degrees for any 10 mile flight line, 1 degree for entire project Flight Info: Aerial photos taken over 6 flights during the window of June 15 to September 15, 2005. All photography also included Global Positioning System (GPS) logging of photo centers. Flight details described below: Flight #1 - (2 planes) * Date: 7/12/2005 * Time: 07:31 - 08:58 (EST) * Aircraft #: N14012 * Camera Type: Zeiss RMK-A 15/23 6 inch (F-4) with Forward Motion Compensation (FMC) * Camera Serial #: 142826 * Magazine Serial #: 117938 * Focal Length (mm): 153.549 * # Flight Lines: 4 * Film: Kodak Aerochrome III Infrared Film 1443 (1443-1411-011-01-012) * Roll #: 1 * Date: 7/12/2005 * Time: 07:44 - 08:42 (EST) * Aircraft #: N3520X * Camera Type: Zeiss RMK-A 15/23 6 inch (F-4) with Forward Motion Compensation (FMC) * Camera Serial #: 144126 * Magazine Serial #: 145781 * Focal Length (mm): 153.328 * # Flight Lines: 6 * Film: Kodak Aerochrome III Infrared Film 1443 (1443-1411-011-01-01/03) * Roll #: 2 Flight #2 - * Date: 7/26/2005 * Time: 08:07 - 09:09 (EST) * Aircraft #: N3520X * Camera Type: Zeiss RMK-A 15/23 6 inch (F-4) with Forward Motion Compensation (FMC) * Camera Serial #: 144126 * Magazine Serial #: 145781 * Focal Length (mm): 153.328 * # Flight Lines: 6 * Film: Kodak Aerochrome III Infrared Film 1443 (1443-1411-011-01-01/03) * Roll #: 3 Flight #3 - * Date: 8/3/2005 * Time: 10:07 - 10:43 (EST) * Aircraft #: N3520X * Camera Type: Zeiss RMK-A 15/23 6 inch (F-4) with Forward Motion Compensation (FMC) * Camera Serial #: 144126 * Magazine Serial #: 145781 * Focal Length (mm): 153.328 * # Flight Lines: 4 * Film: Kodak Aerochrome III Infrared Film 1443 (1443-1411-011-01-01/02) * Roll #: 4 Flight #4 - (2 planes) * Date: 8/25/2005 * Time: 08:04 - 09:42 (EST) * Camera Type: Zeiss RMK-A 15/23 6 inch (F-4) with Forward Motion Compensation (FMC) * Aircraft #: N3520X * Camera Serial #: 144126 * Magazine Serial #: 145781 * Focal Length (mm): 153.328 * # Flight Lines: 8 (includes reflights for recapture due to shadows/other reasons) * Film: Kodak Aerochrome III Infrared Film 1443 (1443-1411-011-01-04/02) * Roll #: 5 * Date: 8/25/2005 * Time: 08:09 - 09:56 (EST) * Aircraft #: N14012 * Camera Type: Zeiss RMK-A 15/23 6 inch (F-4) with Forward Motion Compensation (FMC) * Camera Serial #: 142826 * Magazine Serial #: 117938 * Focal Length (mm): 153.549 * # Flight Lines: 8 * Film: Kodak Aerochrome III Infrared Film 1443 (1443-1411-011-01-01/01) * Roll #: 6 Flight #5 - * Date: 9/2/2005 * Time: 13:47 - 14:42 (EST) * Aircraft #: N3520X * Camera Type: Zeiss RMK-A 15/23 6 inch (F-4) with Forward Motion Compensation (FMC) * Camera Serial #: 144126 * Magazine Serial #: 36295 * Focal Length (mm): 153.328 * # Flight Lines: 4 * Film: Kodak Aerochrome III Infrared Film 1443 (1443-1411-011-01-04/02) * Roll #: 7 Flight #6 - * Date: 9/10/2005 * Time: 08:04 - 08:15 (EST) * Aircraft #: N3520X * Camera Type: Zeiss RMK-A 15/23 6 inch (F-4) with Forward Motion Compensation (FMC) * Camera Serial #: 144126 * Magazine Serial #: 145781 * Focal Length (mm): 153.328 * # Flight Lines: 2 * Film: Kodak Aerochrome III Infrared Film 1443 (1443-1411-011-01-01/02) * Roll #: 8 All flight photography was QA/QC inspected by James W. Sewall Co. prior to shipment to the State of Connecticut, Department of Environmental Protection for final QA/QC. In instances where photos were unacceptable to due to excessive cloud cover, sun reflections or other environmental factors, these areas were reflown. All flight data was recorded POS/AV-DG Inertial Measurement Units.
Aerial Film Processing: Development: Following intial QA/QC process by James W. Sewall Co. and the final QA/QC by the State of Connecticut Department of Environmental Protection, each final film roll was processed by James W. Sewall Co. photo lab technicians. Photo Labeling: After processing, each photo was annotated with the following information: * A numerical abbreviation of the month, day, and year of the exposure (MM/DD/YYYY); * The roll number; * The flight line number; * The exposure number; and * The photo scale The rolls of film were numbered consecutively. Further, the exposure numbers began at one (1) and ran consecutively until the final photo number of the entire project (1129), thus ensuring consecutive and unique numbering for each photo. In addition to the items listed above, the first and last exposures of each flight line also show: * The flight height above mean ground in feet; * The time of exposure (in terms of a twenty-four (24) hour clock set on Eastern Standard Time); and The Zeiss RMK-A 15/23 Camera and CCNS4 Flight Management System also provided additional flight data for each photo. This included: * Date: (YYMMDD) * Time: Greenwich Mean Time (GMT) 24 hr format * Contractor Project ID Number * Location * Flight Line/Line exposure Number/Direction of Flight (degrees) * North Arrow * Contractor Name * Camera F-stop & shutter speed * Latitude/Longitude (Decimal degrees) * Altitude (ft) * Camera Exposure Number Sleeving: Once all film was scanned and the orthophotos were created and delivered, the film rolls were cut and sleeved into transparent archive quality photo envelopes. Each sleeve was labeled with the roll number, flight line number, and unique exposure number.
Aerial Film Scanning: Film was roll scanned on Vexcel 4000 HT photogrammetric scanners at 1000 DPI.
Orthorectification, Mosaicking, & Color Balancing: Orthorectification: Orthophotos combine the image characteristics of a photograph with the geometric qualities of a map. They are created by scanning an aerial photography transparency and then digitally rectifying the scanned image to an orthographic projection. This process georeferences the image and removes image displacements caused by camera tilt and relief of terrain. The 2005 CT Coastal CIR Digital Orthophotos were generated using Inertial Measurement Unit (IMU) exterior orientation data, the scanned versions of the 2005 CT Coastal Aerial Photos and USGS 1:24,000 National Elevation Dataset (NED) Digital Elevation Model (DEM) elevation data within INPHO OrthoMaster V 1.5. Mosaicking: Once each of the photos was orthorectified, they were mosiacked into geographic extents equivalent to 3¾ minutes of latitude and longitude, plus a little overlap based on US Geological Survey (USGS) Quarter Quads. Typically USGS Quarter Quads are comprised of four sections per 7½ minute USGS Quadrangle map area - one each for the northeast, northwest, southeast, and southwest sections. For this project, since the extent of the area photographed may not include coverage for an entire quarter quad section there are cases where there is either no data for parts of a section or no section at all. The ground resolution of the final orthophoto imagery is approximately 1 ft per pixel. Mosaicking was performed in INPHO OrthoVista V 4.1. Colorbalancing: The color qualities of the photographs were affected by a variety of environmental and processing conditions that combine to alter the color and intensity of each image. When the images were mosaicked together these differences in color between images become markedly pronounced. Colorbalancing mitigates these differences, eliminating different color tones and intensities to produce a more visually seamless mosaic across many images. In this case, the color correction did not include the pixel values for large areas of water, which typically skew the results. Colorbalancing was performed in INPHO OrthoVista V 4.1. Once all the orthophotos were mosiacked in to USGS Quarter Quad boundary extents, files were created following the standard USGS fomat, i.e., Q1234_ne, Q1234_nw, Q1234_se, Q1234_sw, etc.
Using ESRI ArcGIS 9.2 software, an empty raster dataset was created and subequently populated with input rasters to create a statewide raster mosaic. STEP 1 - Create Raster Dataset - The Coordinate System for the raster dataset is NAD_1983_StatePlane_Connecticut_FIPS_0600_Feet. The image compression type is JPEG with a compression quality of 75. The Pyramid Reference Point X and Y coordinate are 687800 and 1015180, respectively. Pyramids: 9 Bilinear. The Pixel Type is 8_BIT_UNSIGNED, which supports index values from 0 to 255. Raster statistics were not built. Below is a record of the ESRI Geoprocessing CreateRasterDataset command and arguments that created the empty raster dataset. CreateRasterDataset "Database Connections\10.18.8.94.depgisraster @ DEP_Direct.sde" Ortho_2005_Coast_InfraRed # 8_BIT_UNSIGNED PROJCS['NAD_1983_StatePlane_Connecticut_FIPS_0600_Feet', GEOGCS['GCS_North_American_1983', DATUM['D_North_American_1983', SPHEROID['GRS_1980',6378137.0,298.257222101]], PRIMEM['Greenwich',0.0], UNIT['Degree',0.0174532925199433]], PROJECTION['Lambert_Conformal_Conic'], PARAMETER['False_Easting',999999.999996], PARAMETER['False_Northing',499999.999998], PARAMETER['Central_Meridian',-72.75], PARAMETER['Standard_Parallel_1',41.2], PARAMETER['Standard_Parallel_2',41.86666666666667], PARAMETER['Latitude_Of_Origin',40.83333333333334], UNIT['Foot_US',0.3048006096012192]] 3 DEPRASTER "PYRAMIDS 9 BILINEAR" "128 128" "JPEG 75" "687800 1015180" "Database Connections\10.18.8.94.depgisraster @ DEP_Direct.sde \ Depgisraster.DEP.Ortho_2005_Coast_InfraRed" STEP 2 - Mosaic 98 input rasters. The Mosaicking Tolerance value was set to zero (0). Consequently, pixel values in the raster mosaic resulted from a resampling of pixels values from individual input rasters due to the difference in alignment of input and mosaic (target) pixels. Below is an example usage of the ESRI Geoprocessing Mosaic command and arguments used to mosaic 2 quarter quadrangle input rasters for USGS quadrangle No 98 (Clinton, CT quadrangle). Mosaic Y:\tif_format\q0098SE.tif; Y:\tif_format\q0098SW.tif; "Database Connections\10.18.8.94.depgisraster @ DEP_Direct.sde \ DEPGISRASTER.DEP.ORTHO_2005_COAST_INFRARED" LAST FIRST # # NONE 0 "Database Connections\10.18.8.94.depgisraster @ DEP_Direct.sde \ DEPGISRASTER.DEP.ORTHO_2005_COAST_INFRARED"
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The 2005 Coastal Color Infrared Digital Orthophotography was created in part from aerial triangulation data collected during the flight as well as the 1:24:000 USGS National Elevation Dataset Digital Elevation Model (DEM) for Connecticut. Since this version of a DEM was used ton control the elevation correction, overall accuracy assessment is approximately +/- 50 ft. The State of Connecticut, Department of Environmental Protection has spot checked the 2005 Coastal Color Infrared Digital Orthophotography against existing 2004 Statewide orthophoto basemaps (1:12000 scale and 0.9 ft pixel resolution) and have found the mean accuracy of the 2005 orthophotography to be approximately +/- 9.5 feet. The assessment was performed by identifying common features (roadway markings, sidewalk corners, storm drains, corners of retaining walls, bridge abuttments, etc.) in both datasets and calculating the distances between them. In cases of the "near ground features" (i.e., not including features on bridges, buildings, or other man-made structures) horizontal accuracy increases to +/- 5.5 feet.
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The completeness of the data reflects the content of the data sources, which include the 2005 Connecticut Coastal Color Infrared Aerial Photos. The 2005 Connecticut Coastal Color Infrared Digital Orthophotography layer is complete in the sense that it accurately reflects the content of the 2005 Coastal Color Infrared Aerial Photos available at the time James W. Sewall Co. created the layer. However, compared to current conditions, the 2005 Connecticut Coastal Color Infrared Digital Orthophotography layer is incomplete. This data is not updated.
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No restrictions or legal prerequisites for using the data. The data is suitable for use at appropriate scale, and is not intended for maps printed at scales greater or more detailed than 1:12,000 scale (1 inch = 1,000 feet). Although this data set has been used by the State of Connecticut, Department of Environmental Protection, no warranty, expressed or implied, is made by the State of Connecticut, Department of Environmental Protection as to the accuracy of the data and or related materials. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the State of Connecticut, Department of Environmental Protection in the use of these data or related materials. The user assumes the entire risk related to the use of these data. Once the data is distributed to the user, modifications made to the data by the user should be noted in the metadata. When printing this data on a map or using it in a software application, analysis, or report, please acknowledge the State of Connecticut, Department of Environmental Protection as the source for this information. For example, include the following data source description when printing this layer on a map: "2005 Connecticut Coastal Color Infrared Digital Orthophotography, compiled by James W. Sewall Co. and published by the State of Connecticut, Department of Environmental Protection. Source map scale is 1:12,000."
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The data is in the public domain and may be redistributed. No restrictions or legal prerequisites for using the data. The data is suitable for use at appropriate scale, and is not intended for maps printed at scales greater or more detailed than 1:12,000 scale (1 inch = 1,000 feet). Although this data set has been used by the State of Connecticut, Department of Environmental Protection, no warranty, expressed or implied, is made by the State of Connecticut, Department of Environmental Protection as to the accuracy of the data and or related materials. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the State of Connecticut, Department of Environmental Protection in the use of these data or related materials. The user assumes the entire risk related to the use of these data. Once the data is distributed to the user, modifications made to the data by the user should be noted in the metadata. When printing this data on a map or using it in a software application, analysis, or report, please acknowledge the State of Connecticut, Department of Environmental Protection as the source for this information. For example, include the following data source description when printing this layer on a map: 2005 Connecticut Coastal Color Infrared Digital Orthophotography, compiled by James W. Sewall Co. and published by the State of Connecticut, Department of Environmental Protection. Source map scale is 1:12,000.
| Data format: | in format Raster Dataset (version ArcGIS) |
|---|---|
| Network links: | http://www.ct.gov/deep |
| Media you can order: | disk |
The data distributor does not provide custom GIS analysis or mapping services. Data is available in a standard format and may be converted to other formats, projections, coordinate systems, or selected for specific geographic regions by the party receiving the data.
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