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The National Agriculture Imagery Program (NAIP) acquires aerial imagery during the agricultural growing seasons in the continental United States. It is administered by the USDA's Farm Service Agency (FSA) through the Aerial Photography Field Office (APFO) in Salt Lake City. A primary goal of the NAIP program is to make digital ortho photography available to governmental agencies and the public within a year of acquisition. This "leaf-on" imagery is used as a base layer for GIS programs in FSA's County Service Centers, and is used to maintain the Common Land Unit (CLU) boundaries. Projects are contracted each year based upon available funding and the FSA imagery acquisition cycle. Beginning in 2003, NAIP was acquired on a 5-year cycle. 2008 was a transition year, and a three-year cycle began in 2009. Since the NAIP program began in 2003, vendors have been transitioning to digital sensors in imagery acquisition. In 2009, most NAIP imagery will be acquired with digital sensors rather than film cameras.〔 NAIP imagery products are available either as digital ortho quarter quad tiles (DOQQs) or as compressed county mosaics (CCM). The area for DOQQs corresponds to the USGS topographic quadrangles. Each image tile covers a 3.75 x 3.75 minute quarter quadrangle plus a 300 meter buffer on all four sides. CCMs are generated by compressing DOQQ image tiles into a single mosaic. All individual tile images and the resulting mosaic are rectified in the UTM coordinate system, NAD 83, and cast into a single predetermined UTM zone.〔 NAIP imagery is acquired at a one-meter ground sample distance (GSD) with a horizontal accuracy that matches within six meters of photo-identifiable ground control points. The default spectral resolution is natural color (Red, Green and Blue, or RGB) but beginning in 2007, some states have been delivered with four bands of data: RGB and Near Infrared. Images have no more than 10% cloud cover per quarter quad tile, weather conditions permitting.〔 ==References== 〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「National Agriculture Imagery Program」の詳細全文を読む スポンサード リンク
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