Illinois 2011 IDOT Imagery Mosaic

Overview The Illinois Department of Transportation (IDOT) coordinated the funding and acquisition of the 2011 digital orhtophotography for 95 counties in Illinois. The metropolitan Chicago area including Cook, DuPage, Kane, Kendall, Lake, McHenry and Will counties were not acquired as part of this IDOT project. The native projection for the 2011 IDOT orthophotography is transverse Mercator, Illinois State Plane Coordinate System (SPCS), West and East zones, NAD 1983 datum. For the purposes of data delivery and distribution, the orthophotography is organized into data tiles, each covering a geographic area of 10,000 ft. x 10,000 ft. The ground spatial resolution of each orthophoto tile is 1 ft. x 1 ft. per pixel for 93 of the 95 Illinois counties. Because of a county cost-sharing option made available as part of the 2011 IDOT orthophotography project, higher resolution orthophotography with a ground spatial resolution 0.5 ft. x 0.5 ft. was processed and is available for Sangamon and Tazewell Counties, as well as a portion of Woodford County. Each data tile was created utilizing multiple aerial images. The metadata for each tile will show the date the imagery was captured. Images were captured between March 16th and May 30th, 2011, using a Z/I Imaging Digital Mapping Camera (DMC). The DMC system collects imagery in four spectral bands, and therefore users can select between either a natural color rendition (RGB = 1,2,3) or near-infrared rendition (RGB = 4,1,2) for a particular application: Band 1 = Red (598-675 nm) Band 2 = Green (500-650 nm) Band 3 = Blue (400-580 nm) Band 4 = Near-IR (675-850 nm) This Image Service provides a mosaic dataset of 2011 imagery for Illinois Department of Transportation coverage. It is delivered as an ImageServer with 4-band raster data, AMD dataset format, and 0.1524 meter pixel size, offering detailed statewide image coverage in Web Mercator spatial reference 102100. The service supports Image, Metadata, Catalog, and Download access. It is provided by the Illinois State Geological Survey. Band Characteristics The raster contains 4 bands named Band_1, Band_2, Band_3, and Band_4. Pixel Type: 8-bit unsigned integer Band Count: 4 Value Range: 0 to 255 in each band Mean Values: Band 1: 114.68, Band 2: 113.68, Band 3: 107.30, Band 4: 139.45 Standard Deviations: Band 1: 49.36, Band 2: 48.59, Band 3: 45.64, Band 4: 56.03 Raster Properties Pixel Size: 0.15240030480060965 by 0.15240030480060968 meters Dataset Format: AMD Compression Type: None Resampling Method: Bicubic Maximum Display Size: 15,000 by 4,100 pixels Tile Size: 2048 by 256 pixels Histogram Support: Available Raster functions are enabled, with None listed as the available raster function option. Mosaic Properties This service is built from a mosaic dataset and combines raster items on the fly. The default mosaic method is Northwest, with additional options for Center, LockRaster, ByAttribute, Nadir, Viewpoint, Seamline, and None. The mosaic operator is First, and up to 20 images can be composited at once. Catalog fields support item-level querying and review of mosaic metadata, including Name, Category, Tag, GroupName, ProductName, CenterX, CenterY, ZOrder, Shape_Length, and Shape_Area. The Category field uses coded values for mosaic catalog item types such as Primary, Overview, Inactive, Uploaded, and Custom. Geographic Coverage The service covers a broad area across Illinois in Web Mercator coordinates. Spatial Reference: 102100 Use Cases The service supports image viewing, catalog exploration, metadata review, and raster download workflows. It allows copying and analysis, with download access limited to 20 images per request and a 2048 MB size limit. Query operations support statistics, advanced queries, ordering, pagination, and distinct values, with a maximum record count of 1000. Source and Credit: Illinois State Geological Survey.