This data set is a statewide raster mosaic of 2006, natural color, 1 meter ground sample distance imagery for Connecticut from the National Agriculture Imagery Program (NAIP). NAIP acquires digital ortho imagery during the agricultural growing seasons in the continental United States. A primary goal of the NAIP program is to enable availability of ortho imagery within one year of acquisition. NAIP provides two main products: 1 meter ground sample distance (GSD) ortho imagery rectified to a horizontal accuracy of within +/- 5 meters of reference digital ortho quarter quads (DOQQ's) from the National Digital Ortho Program (NDOP); and, 2 meter GSD ortho imagery rectified to within +/- 10 meters of reference DOQQs. The tiling format of NAIP imagery is based on a 3.75' x 3.75' quarter quadrangle with a 300 meter buffer on all four sides. NAIP quarter quads are formatted to the UTM coordinate system using NAD83. NAIP imagery may contain as much as 10% cloud cover per tile.
NAIP imagery is available for distribution within 60 days of the end of a flying season and is intended to provide current information of agricultural conditions in support of USDA farm programs. For USDA Farm Service Agency, the 1 meter GSD product provides an ortho image base for Common Land Unit boundaries and other data sets. The 1 meter NAIP imagery is generally acquired in projects covering full states in cooperation with state government and other federal agencies who use the imagery for a variety of purposes including land use planning and natural resource assessment. With an annual cycle, NAIP is also used for disaster response often providing the most current pre-event imagery. While suitable for a variety of uses the 2 meter GSD NAIP imagery is primarily intended to assess crop condition and compliance to USDA farm program conditions. The 2 meter imagery is generally acquired only for agricultural areas within state projects.
This statewide raster mosaic was prepared by the State of Connecticut, Department of Environmental Protection (CT DEP) using 2006, 3 color band, 1 meter ground sample distance imagery (input rasters) from the USDA-FSA-APFO Aerial Photography Field Office. These original input rasters are in GeoTIFF format and because there are two UTM Zones in Connecticut, the input rasters are in either the NAD 1983 UTM Zone 18N Meters or NAD 1983 UTM Zone 19N Meters. The individual rasters were projected to NAD 1983 StatePlane Connecticut FIPS 0600 Feet and merged together in the resulting statewide mosaic.
ground condition
Users should be aware that this is an interim release. May contain defects and have horizontal accuracy less than the specified tolerances. Imagery may be replaced to address defects found in a small number of products through quality assurance processes. Imagery containing defects that require the acquisition of new imagery, such as excessive cloud cover, specular reflectance, etc., will not be replaced within a NAIP project year.
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FSA Digital Orthophoto Specs.
Digital Georectifed Image (2006 NAIP 1 meter DOQQ). Each image is in GeoTIFF format. Depending in the location, NAIP quarter quads are either in NAD 1983 UTM Zone 18N or NAD 1983 UTM Zone 19N coordinate system. UTM Zones 18N and 19N encompass portions of Connecticut. NAIP DOQQ (3.75 minute tile) file names are based on the USGS quadrangle naming convention.
Statewide raster mosaic of all NAIP DOQQ input rasters. The raster mosaic is in the Connecticut State Plane Coordinate System, North American Datum of 1983 (NAD83).
The imagery was collected at a flying height of 28000 ft above mean terrain with 20% sidelap using an ADS40 digital sensor, giving the collected data nominal ground sampling distance of 0.9 meters. Collected data was downloaded to portable hard drives and shipped to the processing facility daily. Airborne GPS / IMU data was processed and reviewed to ensure sufficient accuracy for project requirements. Planar rectified images were generated from the collected data for use in image quality review. The planar rectified images were generated at five meter resolution using a two standard deviation histogram stretch. Factors considered during this review included but were not limited to the presence of smoke and/or cloud cover, contrails, light conditions and sun glint. Aerotriangulation blocks were defined primarily by order of acquisition and consisted of one to ten strips. Terrain points providing the observations for the least squares bundle adjustment were selected from the images using an autocorrelation algorithm. Photogrammetric control consisted of photo identifiable points selected from base imagery provided by USDA FSA APFO. Elevations for the control points were sampled from USGS NED DEMs. The control points were loaded in to a softcopy workstation and measured in the collected imagery. A least squares bundle adjustment of terrain points, control points and the ABGPS was performed to develop an aerotriangulation solution for each block. Precedence was given to the photo identifiable control points over control provided by the ABGPS solution in the bundle adjustment to ensure the final solution would agree with the provided base imagery within the required tolerances. The triangulated strips were ortho-rectified to the USGS NED DEM for the project area. The images were re-sampled from the raw resolution of 0.9 meters to the required resolution of 1.0 meters using a cubic convolution filter during the process. The red, green and blue bands were combined to generate a final ortho-rectified image strip. The ADS40 sensor collects twelve bit image data which requires radiometric adjustment for output in standard eight bit image channels. The ortho-rectified image strips were produced with the full 12 bit data range, allowing radiometric adjustment to 8 bit range to be performed on a strip by strip basis during the final mosaicing steps. The imagery was mosaicked using a combination of automated and manual seamline generation. The 12 bit data range was adjusted for display in standard eight bit image channels by defining a piecewise histogram stretch. A constant stretch was defined for each image collection period, and then strip by strip adjustments were made as needed to account for changes in sun angle and azimuth during the collection period. Automated balancing algorithms were applied to account for bi-directional reflectance as a final step before the conversion to 8 bit data range. APFO specified DOQQs were extracted from the final mosaic in GeoTIFF format. Final DOQQs were reviewed for artifacts and anomalies and adjusted as part of quality control procedures. When necessary, local corrections to the imagery were performed to minimize the effects of such artifacts. GeoTIFF tags for the appropriate UTM zone were then applied to all images.
Using ESRI ArcGIS 9.2 software, an empty raster dataset was created and subequently populated with input rasters to create a statewide raster mosaic. The State of Connecticut, Department of Environmental Protection obtained these input rasters from the Tolland State Office of the NRCS at 344 Merrow Road, Suite A, Tolland, Connecticut 06084-3917. 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 90. The Pyramid Reference Point X and Y coordinate are 687800 and 1015180, respectively. Bands: 3. Pyramids: 8 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_2006_Color_Load # 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 8 BILINEAR" "128 128" "JPEG 90" "687800 1015180" "Database Connections\10.18.8.94.depgisraster@DEP_Direct.sde\depgisraster.DEP.Ortho_2006_Color"\ STEP 2 - Mosaic 410 of 411 quarter quadrangle input rasters that cover Connecticut. Due to poor image quality, one quarter quad, Amenia SE (n_4107312_se_18_1_20060731_20070319.tif), was not included in the statewide mosaic. The Ignore Background Value was set to one (1). The NoData value was left blank. 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. Note, in the resulting mosaic, the input rasters in NAD 1983 UTM Zone 18N Meters and NAD 1983 UTM Zone 19N Meters were projected to NAD 1983 StatePlane Connecticut FIPS 0600 Feet. Below is an example usage of the ESRI Geoprocessing Mosaic command and arguments used to mosaic 8 (quarter quadrangle) input rasters in TIFF format. Mosaic D:\tif_fomat\42073\n_4207361_se_18_1_20060716_20070201.tif D:\tif_fomat\42073\n_4207361_sw_18_1_20060716_20070201.tif; D:\tif_fomat\42073\n_4207362_se_18_1_20060805_20070201.tif; D:\tif_fomat\42073\n_4207362_sw_18_1_20060805_20070201.tif; D:\tif_fomat\42073\n_4207363_se_18_1_20060814_20070201.tif; D:\tif_fomat\42073\n_4207363_sw_18_1_20060814_20070201.tif; D:\tif_fomat\42073\n_4207364_se_18_1_20060814_20070201.tif; D:\tif_fomat\42073\n_4207364_sw_18_1_20060814_20070201.tif "Database Connections\depdbs11.depgisraster@DEP.sde \DEPGISRASTER.DEP.ORTHO_2006_COLOR_LOAD" LAST FIRST 1 # NONE 0 "Database Connections\depdbs11.depgisraster@DEP.sde \DEPGISRASTER.DEP.ORTHO_2006_COLOR_LOAD"
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24-bit pixels, 3 band color(RGB) values 0 - 255
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In no event shall the creators, custodians, or distributors of this information be liable for any damages arising out of its use (or the inability to use it).
Natural Color
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Although these data have been used by the State of Connecticut, no warranty, expressed or implied, is made by the State of Connecticut as to the accuracy of these 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 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.
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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