The dataset consists of tiled orthogonal imagery produced from nadir images captured by Pictometry International. Automatic aerial triangulation (AAT) was performed. The triangulated frames were rectified to a LiDAR derived DEM. Mosaicking was performed using an automatic seaming algorithm and manually edited to eliminate seams through elevated features where possible.
The dataset consists of tiled orthogonal imagery produced from nadir images captured by Pictometry International.
The dataset consists of tiled orthogonal imagery produced from nadir images captured by Pictometry International.
The dataset consists of tiled orthogonal imagery produced from nadir images captured by Pictometry International.
This digital geospatial file consists of a series of raster digital orthophoto images covering all of Cook, DuPage, Grundy, Kane, Kendall, Lake, McHenry, and Will County, Illinois. The images have a pixel resolution of 0.5 feet which generated an orthophotographic database with a mapping scale of 1\" = 100'. The imagery for the \"Countywide Flight\" was collected between March 9th, 2012 and May 11th, 2012. The imagery for the \"Special Consideration Area\" was collected on March 10th, 2012 and May 13th, 2012. (Refer to the relevant Process Step for a description of the principal differences between these two flights.) A digital orthoimage is a raster image of remotely sensed data that has had displacement in the image introduced by sensor orientation and terrain relief removed. Digital orthoimages combine the image characteristics of photography with the geometric qualities of maps. The normal orientation of this data is by lines (rows) and samples (columns). Each sample in this data set contains a series of pixels ordered from west to east with the order of the lines from north to south. The data set is tiled for dissemination into 18,905 separate tiles, each of which is 2500 feet on a side. This digital geospatial file has been orthorectified using survey control points obtained through both Airborne Global Positioning Systems and Ground Control Survey. This dataset is projected using the Transverse Mercator map projection. The grid coordinate system used is the Illinois State Plane Coordinate System, East Zone (Zone Number Zone 3776, FIPS 1201), NAD 83 (NSRS2007) (horizontal datum), with ground coordinates expressed in U.S. Survey Feet. Each tile consists of two files, a TIFF (Tagged Image File Format) (.tif), and an ASCII geo-referencing header file (.tfw). Each tile is approximately 100MB in size resulting in a total of 1.9TB for the region.
This digital geospatial file consists of a series of raster digital orthophoto images covering all of Cook, DuPage, Grundy, Kane, Kendall, Lake, McHenry, and Will County, Illinois. The images have a pixel resolution of 0.5 feet which generated an orthophotographic database with a mapping scale of 1\" = 100'. The imagery for the \"Countywide Flight\" was collected between 11 May, 2009 and 2 August, 2009. The imagery for the \"Special Consideration Area\" was collected on 17 and 22 of May, 2009. (Refer to the relevant Process Step for a description of the principal differences between these two flights.) A digital orthoimage is a raster image of remotely sensed data that has had displacement in the image introduced by sensor orientation and terrain relief removed. Digital orthoimages combine the image characteristics of photography with the geometric qualities of maps. The normal orientation of this data is by lines (rows) and samples (columns). Each sample in this data set contains a series of pixels ordered from west to east with the order of the lines from north to south. The data set is tiled for dissemination into 18,905 separate tiles, each of which is 2500 feet on a side. This digital geospatial file has been orthorectified using survey control points obtained through both Airborne Global Positioning Systems and Ground Control Survey. This dataset is projected using the Transverse Mercator map projection. The grid coordinate system used is the Illinois State Plane Coordinate System, East Zone (Zone Number Zone 3776, FIPS 1201), NAD83/97 HARN (horizontal datum), with ground coordinates expressed in U.S. Survey Feet. Each tile consists of two files, a TIFF (Tagged Image File Format) (.tif), and an ASCII geo-referencing header file (.tfw). Each tile is approximately 100MB in size resulting in a total of 1.9TB for the region.
This task order consists of digital orthophoto production covering the Chicago IL-IN, 133 UA - Will County, Illinois.
This data set contains imagery from the National Agriculture Imagery Program (NAIP). NAIP acquires digital ortho imagery during the agricultural growing seasons in the continental U.S.. A primary goal of the NAIP program is to enable availability of ortho imagery within one year of acquisition. NAIP provides four 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); 2 meter GSD ortho imagery rectified to within +/- 10 meters of reference DOQQs; 1 meter GSD ortho imagery rectified to within +/- 6 meters to true ground; and, 2 meter GSD ortho imagery rectified to within +/- 10 meters to true ground. 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. This file was generated by compressing NAIP quarter quadrangle tiles that cover a county. MrSID compression, with mosaic option, was used. Target values for the compression ratio are (15:1) and maximum number of compression levels are used.
The project is to complete 1\"=100' scale mapping using 1\"=763' Digital Mapping Camera aerial photography. Analytical aerotriangulation was done to provide complete photo control for mapping and orthophoto production. There are 3515 photos in the aerotriangulation. Post flight processing of the digital aerial data was completed at Aero-Metric, Inc.
The project location is Will County, Illinois.
Control units are in feet. Coordinate system is Illinois State Plane, East Zone on NAD 83/97 horizontal datum. Vertical datum is NGVD 88. Airborne-gps control for 3510 photos was completed by Aero-Metric, Inc. Ground-control eastings, northings and elevations were surveyed by Aero-Metric, Inc. During the initial flight of line 27 (on 11/22/06) the flight was diverted to avoid other air traffic. The initial re-flight left a gap of three images in the usable coverage. This was re-flown on 4/13/07 and five images were manually measured and tied to the surrounding AB/GPS controlled photography.
A combination of auto-correlated and manually measured points were used to establish pass points, strip tie points and horizontal and vertical check points. The auto-correlation was accomplished using the 'Image Station Automatic Triangulation (ISAT) program from 'Intergraph'.
The calibrated focal length for all photos is 120 mm. The photo dates are 11/20, 22 & 23/06 and 4/13/07.
This data set contains imagery from the National Agriculture Imagery Program (NAIP). NAIP acquires digital ortho imagery during the agricultural growing seasons in the continental U.S.. 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 +/- 3 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. This file was generated by compressing NAIP quarter quadrangle tiles that cover a county. MrSID (MG3) compression, with mosaic option, was used. Target values for the compression ratio are (15:1) and compression levels(9) are used.
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. The projected coordinate system is UTM with a NAD83 datum. There is no image overlap between adjacent files.
This dataset was produced from digital color orthophotography that was flown by AirPhotoUSA in October, 2002 for the entire county. The original raster data was stored in MAP format accessible only within AirPhotoUSA's PhotoMapper application.
195 Separate image TIF files were extracted from the original 2 images supplied by AirPhotoUSA. These TIF files were imported into an ArcSDE raster layer.
Each TIF file is approximately 105 Megabytes and covers a ground area of roughly 150,000 square feet. The ArcSDE raster layer is comprised of 195 TIF files that are joined seamlessly. The TIF files are organized by row, there is a total of 22 rows with a maximum of 13 TIF files on any single row.
Digital orthophoto imagery (DOI) at photo scales of 1:2000 and 1:800 were produced by Kucera from photography gathered in 1997. From this imagery, mapping scales of 1:400 and 1:100 were produced and are currently in use. These mapping scales are accurate to within 10 feet and 5 feet, respectively.
The project involves scanning of the CMAP’s collection of historic aerial photography for 6 counties (Cook, DuPage, Kane, Lake, McHenry and Will) in Northeastern Illinois, and georeferencing them for archival purposes, GIS-friendliness and public access through the CMAP website. Photos of the region were generally taken every five years, beginning in 1970, and printed on large Mylar sheets, which have limited usefulness in the age of GIS and open data. The scanning and georeferencing is an ongoing project, which began in 2013 with the photographs from 1995. This document pertains to the procedures used for that set, and the technical issues encountered.
The primary data set consists of historical black and white aerial photographs for Will County, Illinois acquired between August 14 and September 16, 1961. The original paper prints have been scanned and stored as TIFF format images. The online images available are MrSID format images in which the original TIFF files have been compressed. The original photographic paper prints are at a scale 1:20,000.
The primary data set consists of historical black and white aerial photographs from Illinois acquired during 1936 to 1941. Alternative years of photography are used for certain counties when a quality set from between 1936 and 1941 cannot be located. The original paper prints have been scanned and stored as TIFF format images. The online images available are MrSID format images in which the original TIFF files have been compressed at a target ratio of 12:1 with the exception of 17 counties. Alexander, Boone, DeWitt, Douglas, Edwards, Gallatin, Hardin, Jackson, JoDaviess, Massac, Menard, Perry, Pope, Randolph, Saline, Williamson and Winnebago Counties were compressed at a target ratio of 6:1. The original photographic paper prints are at a scale 1:20,000.