2005 Illinois Chicago Urban Area Orthophotography | clearinghouse.isgs.illinois.edu

Data

Summary

Chicago Urban Area (CUA) orthoimagery data have been created for the counties of Cook, DuPage, Kane, Lake, McHenry, and Will in northeastern Illinois in two projections. These are Universal Transverse Mercator (UTM) with a NAD83 datum, Zone 16 and Illinois State Plane East Zone (SPE) with a NAD83 datum. Data were created using US Geological Survey Urban Area specifications on true-color film during the leaf-off period of spring, 2005 at a 1 foot by 1 foot resolution. Each data tile was created utilizing multiple aerial images. Images were captured on the following dates in 2005: March 28, April 4, April 8, April 14, and May 4. Programmatic details for CUA data were outlined in Illinois GIS Notes, Winter 2005.

Metadata

cua05_meta.html

Data

Data Distribution: Compressed Data

Compressed data are LizardTech's MrSID Generation 2 .sid files. Target compression ratio was 8:1; one compressed file is roughly 9 megabytes in size.

A statewide collection of both 2005 CUA data (40 Gigabytes) and 2005 National Aerial Photography Program (NAPP) data requires about 100 Gigabytes of storage space. We do not plan to distribute compressed data files by any other means (cd-rom, zip drives, portable drives, ftp download, etc).

The collection can be viewed as an Image Service on the Viewer tab of this webpage, or in ArcGIS Desktop, ArcGIS.com or any client application that can consume Esri Image Services.

CUA 2005 compressed data will be available soon via an interactive map for downloading.

Compressed .zip file bundles contain:

<filename>.sid - compressed image

<filename>.aux - georeferencing information, associated with .sid image

<filename>.sdw - georeferencing information, associated with .sid image

<filename>.xml - metadata file for uncompressed GeoTIFF image, not edited for compressed image

File indexes:

cua_isgs_indexes.zip - shapefile file indexes for the UTM and SPE projections.

Resources:

cua05archive.zip - data archive directories for the UTM and SPE projections.

UTM file naming convention based on the United States National Grid (USNG).

State Plane file naming convention based on data tile coordinates.

Data Distribution: Uncompressed Data

The ArcIMS interactive map was created for the Universal Transverse Mercator data by loading the original GeoTIFF files into ArcSDE.

Contact the Illinois State Library(link is external) to obtain indiviual, uncompressed Illinois 2005 orthoimagery files. Note that one statewide collection of uncompressed 2005 CUA data (310 to 320 Gigabytes) and 2005 NAPP data would require about 1 Terabyte of storage space.

Services

https://data.isgs.illinois.edu/arcgis/rest/services/Imagery/IL_CUA_2005/ImageServer

Viewer

Project Sponsors

Project Sponsors:

Illinois Department of Public Health

Illinois Department of Military Affairs

Illinois Environmental Protection Agency

Federal Geographic Data Committee

US Geological Survey

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Data

Data Distribution: Compressed Data

File indexes:

Resources:

Data Distribution: Uncompressed Data

Project Sponsors: