Dhamayanti’s Weblog

New Mapping Information Providing Better Support for Flood Management in California

Fugro EarthData is currently producing digital orthoimagery and lidar mapping over large portions of California’s Central Valley. The work is being performed for the California Department of Water Resources for four regional areas, two of which are under contract to engineering firms CH2M Hill and HDR. Mapping data is scheduled for delivery by the end of 2008 and represents the first phase of support for the State’s multi-million dollar investment in the State Plan of Flood Control and the Central Valley Flood Protection Plan. These projects will provide the critical foundation necessary to understand and reduce flood risk throughout the urban and rich agricultural regions.

Fugro EarthData’s work on the project extends over two sections of the Central Valley—the Upper Sacramento and Lower San Joaquin floodplains, each comprising areas of approximately 2,000 square miles. Deliverables for both areas include four-band orthoimagery at a 6-inch pixel resolution with the Upper Sacramento area also receiving stereo pairs of the imagery for future 3D planimetric and topographic data compilation. The mapping is being accomplished using Fugro EarthData’s all-digital system, which combines the Leica ADS40-SH52 digital camera with Pixel Factory processing.

In addition to the orthoimagery, the Lower San Joaquin area also involves lidar mapping for creation of a digital elevation model, development of hydrographic breaklines, and production of 1-foot contours. Data is being collected using Fugro EarthData’s Leica ALS50-II lidar system. Existing high-resolution lidar datasets collected by helicopter along area levees will be merged into the final elevation models. The helicopter data was acquired by John Chance Land Surveys—also a Fugro company—using its unique FLI-MAP system.

State-of-the-Art Land-Use/Land-Cover Mapping in South Carolina

Maximizing the value of new aerial data acquired this spring using a Leica ADS40 digital camera for its orthoimagery update, Horry County, South Carolina, has awarded Fugro EarthData an add-on contract to produce countywide land-use/land-cover mapping. The effort will support evaluation of impervious surfaces, drainage patterns, and many more land-use management applications important to this coastal county,” said Bill Shinar, Fugro EarthData regional business manager.

The land-use/land-cover work will draw on all four multi-spectral bands—red, green, blue, and near-infrared—collected by the ADS40 camera during the spring mission. “The ability to produce multiple products in different data renditions from a single flight demonstrates the power of the Leica ADS40 digital camera used by Fugro EarthData,” Shinar said.

In producing the land-use/land-cover data, Fugro EarthData will employ an automated, object-oriented image classification approach, combined with a classification and regression tree (CART) analysis for polygon labeling. Unlike traditional methods, which classify imagery at the pixel level, this technique analyzes data objects (polygons) to incorporate shape and context in the classification. The result is a more accurate and detailed thematic map that capitalizes on the characteristics of the County’s high resolution digital imagery. Fugro EarthData will begin the project this month with final deliverables scheduled for November.

oR Link aja ke alamat ini : <http://www.fugroearthdata.com/locations.php>