Data Management Plan

This data set contains imagery from the National Agriculture

Imagery Program (NAIP). NAIP acquires digital ortho imagery

during the agricultural growing seasons in the continental U.S..

A primary goal of the NAIP program is to enable availability of

of ortho imagery within one year of acquisition. NAIP provides

four main products: 1 meter ground sample distance (GSD) ortho

imagery rectified to a horizontal accuracy of within +/- 5

meters of reference digital ortho quarter quads (DOQQ's) from

the National Digital Ortho Program (NDOP); 2 meter GSD

ortho imagery rectified to within +/- 10 meters of reference

DOQQs; 1 meter GSD ortho imagery rectified to within +/- 6

meters to true ground; and, 2 meter GSD ortho imagery rectified

to within +/- 10 meters to true ground. The tiling format of

NAIP imagery is based on a 3.75' x 3.75' quarter quadrangle

with a 300 meter buffer on all four sides. NAIP quarter quads

are formatted to the UTM coordinate system using NAD83. NAIP

imagery may contain as much as 10% cloud cover per tile.

Process Steps:

• 2012-09-17 00:00:00 - Digital imagery was collected at a nominal GSD of 1.0m using seven Cessna 441 aircrafts flying at an average flight height of 9052m AGL. All aircraft flew with Leica Geosystem's ADS80/SH82 digital sensors with firmware 3.20 or newer. Each sensor collected 11 image bands. PanF27A,PanF02A and PanB14A panchromatic bands with a spectral range of 465-676nm. RedN00a and RedB16a with a spectral range of 604-664nm. GrnN00a and GrnB16a with a spectral range of 533-587nm. BluN00a and BluB16a with a spectral range of 420-492nm and Near-infrared bands NirN00a and NirB16a with a spectral range of 833-920nm. The CCD arrays have a pixel size of 6.5 microns in a 12000x1 format. Both the CCD's and the A/D convertors have a dynamic range of 12bits. The data is stored in 16bit format. The ADS is a push-broom sensor and the ground footprint of the imagery at NAIP scale is 12km wide by the length flightline. The maximum flightline length is limited to approximately 240km. The factory calibrations and IMU alignments for each sensor (Serial Numbers: 1321, 30011, 30012, 30014, 30017, 30022, 30034, and 30103) were tested and verified by in-situ test flights before the start of the project. The Leica ADS Flight Planning and Evaluation Software (FPES) is used to develop the flight acquisition plans. Flight acquisition sub blocks are designed first to define the GNSS base station logistics, and to break the project up into manageable acquisition units. The flight acquisition sub blocks are designed based on the specified acquisition season, native UTM zone of the DOQQs, flight line length limitations (to ensure sufficient performance of the IMU solution) as well as air traffic restrictions in the area. Once the sub blocks have been delineated they are brought into FPES for flight line design. The design parameters used in FPES will be 30% lateral overlap and 1.0m resolution. The flight lines have been designed with a north/south orientation. The design takes into account the latitude of the state, which affects line spacing due to convergence as well as the terrain. SRTM elevation data is used in the FPES design to ensure the 1m GSD is achieved over all types of terrain.
• 2012-09-17 00:00:00 - The raw data was downloaded from the sensors after each flight using Leica XPro software. The imagery was then georeferenced using the 200Hz GPS/INS data creating an exterior orientation for each scan line (x/y/z/o/p/k). Technicians precisely measured tie points in 3 bands/looks (Back/Nadir/Forward) for each line using Leica Xpro software. The resulting point data and exterior orientation data were used to perform a full bundle adjustment with ORIMA software. Blunders were removed, and additional tie points measured in weak areas to ensure a robust solution. Once the point data was clean and point coverage was acceptable, photo-identifiable GPS-surveyed ground control points were introduced into the block adjustment. The bundle adjustment process produces revised exterior orientation data for the sensor with GPS/INS, datum, and sensor calibration errors modeled and removed. Using the revised exterior orientation from the bundle adjustment, orthorectified image strips were created with Xpro software and the April 2012 USGS 10m NED DEM. The Xpro orthorectification software applies an atmospheric-BRDF radiometric correction to the imagery. This correction compensates for atmospheric absorption, solar illumination angle and bi-directional reflectance. The orthorectified strips were then overlaid with each other and the ground control to check accuracy. Once the accuracy of the orthorectified image strips were validated the strips were then imported into Inpho's OrthoVista 4.6 package which was used for the final radiometric balance, mosaic, and DOQQ sheet creation of the final DOQQ sheets, with a 300m buffer and a ground pixel resolution of 1m.