Choctaw Geo Imaging (CGI), a digital mapping service provider of CHAHTA Enterprises, has completed production of its nationwide geoORTHO dataset. CGI enhanced the library of USGS Digital Orthophoto Quarter Quad (DOQQ) aerial imagery through radiometric balancing, black & white conversion, and seamless mosaicking. CGI’s Illinois production facility processed over 200,000 images in less than nine months, completing the project ahead of its original schedule. In a related statement, CGI has reached an agreement with IntraSearch, Inc. to distribute the seamless geoORTHO dataset through the MapMart.com website.
“The success of the geoORTHO project demonstrates CGI’s ability to manage large and comprehensive data processing with high quality and efficiency,” commented Brenda Burroughs, Vice President of Sales and Marketing of CGI. “Our team is capable of delivering a variety of geospatial production solutions, from feature extraction services to advanced image processing. CGI is well equipped to process imagery from a variety of satellite and aerial sources.”
CGI established a partner agreement with IntraSearch to distribute the geoORTHO dataset. IntraSearch is a Denver-based firm providing custom aerial photography , photogrammetric services, orthorectification, digital conversions, scanning, plotting, computer assisted design (CAD) and geographic information systems (GIS) solutions for both public and private sector clients and online mapping products and services via the MapMart website. IntraSearch has provided professional mapping services for over fifty years and continues to be on the cutting-edge with new mapping and related technologies.
“IntraSearch evaluated many products in a search to complement our existing MapMart datasets,” explained Michael Platt, President of IntraSearch. “The quality of the geoORTHO data far exceeded everything else we’ve seen. We look forward to working with CGI and providing our customers with this new seamless aerial imagery. The imagery will be viewable online and immediately downloadable by a user defined area.”
The geoORTHO project involved transforming the varied specifications of DOQQ coverage into a unified, standardized black-and-white mosaic of available U.S. aerial imagery. CGI began with color infrared and black-and-white DOQQ data formatted as GeoTIFF files with associated header text files. The GeoTIFF files were reformatted as tiled images. Color infrared imagery was converted to black-and-white using an IHS transform.
The 580-megabyte geoORTHO tiles have been projected in WGS 84, utilizing the NIMA-developed ARC projection. The geoORTHO data is stored as a database, enabling output of consistent orthoimagery to a wide variety of datums, projections, and file formats. Each tile has 80 meters of overlap with adjacent images. This, together with the mosaicking of sixteen DOQQs per tile, dramatically reduces the file size even before image compression. The lower file size enables user to load, manage, and store the geoORTHO data more efficiently than standard DOQQ files.