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User Manual - pancroma

User Manual - pancroma

User Manual - pancroma

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43. Working with NAIP Data________________________________________________________________The National Agriculture Imagery Program (NAIP) acquires aerial imagery duringthe agricultural growing seasons in the continental United States. The primarygoal of the NAIP program is to make digital ortho photography available togovernmental agencies and the public.NAIP image acquisitions are contracted each year for different regions of thecountry, with the entire country currently being covered during a three-year cycle.The acquisition is timed to result in "leaf-on" imager. The images are one-meterresolution, orthorectified with a 6-meter ground accuracy. Prior to 2007, threebands corresponding to the visible blue, green and red spectra were collected.After that year, a fourth near infrared (NIR) band was added. Google Earth usesNAIP data extensively as its high resolution layer in the continental USA.The four band data can be downloaded from the USGS The National Map Viewerand Download Platform. The four bands are bundled into a single file offered inGeoTiff and JPEG2000 format. Instructions for downloading this data are offeredat the USGS website. Limited metadata is offered with the images. Sensor datadoes not seem to be readily available, for example the band sensitivities.To access NAIP four band data, download your area of interest from the USGSNational Map Viewer. The USGS offers a lot of data from this site, but you willwant the Orthoimagery product, NAIP 4 Band. Once you download the dataaccording to the instructions on the website, you must unbundle the single fileinto four separate band files as described in previous sections. To do so select‘Decompose Bundles’ | ‘Four File NAIP Data’ from the Main Menu. When the fileopens, you will be prompted for a base file name. Input and save as GeoTiff.The band number designations will be atomically appended to your selectedbase file name.The main disadvantage of NAIP data is that it consists of only four bands. Theadvantage is its coverage and resolution (1 meter). And it is free. Forinformation regarding use of NAIP data for multispectral analysis, see thesubsequent sections describing the PANCROMA TM Point Spectrum Generator TMand Spectral Analyzer TM .121

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