MIL-PRF-89041 Controlled Image Base \(Cib\)This specification provides requirements for the preparation and use of the Raster Product Format \(RPF\) Controlled Image Base \(CIB\) data. CIB is a dataset of orthophotos, made from rectified grayscale aerial images. CIB supports various weapons, C3I theater battle management, mission planning, digital moving map, terrain analysis, simulation, and intelligence systems. CIB data are produced from digital source images that can be converted to meet the requirements of this CIB specification at one of the registered resolutions defined in MIL-STD-2411-1. CIB data are derived directly from digital images and are compressed and reformatted to conform to the RPF Standard. CIB files are physically formatted within a National Imagery Transmission Format \(NITF\) message.

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MIL-PRF-89041A

origin for counting polar frames is the lower-left corner of the

polar zone, with rows and columns numbered from that origin.

3.5.4

Nonpolar frame overlap.

a. The longitudinal and latitudinal extents of the zones in

the southern hemisphere are identical to those in the northern

hemisphere.

b. Rows of frames from different zones do not have the same

longitudinal extent since the longitudinal pixel intervals

differ.

c. For each nonpolar zone N, the top-most frame row of that

zone corresponds (in latitude) with the bottom-most frame row of

zone N+1 (as depicted in FIGURE 3). Thus the frames at the top

and bottom rows of each zone shall overlap frames of those zones

above and below. In each ARC zone, the lower-left pixel in

lower-left frame file is edge-aligned with the ARC system origin.

3.5.5 Frame and subframe structure for polar regions. The

CIB frame and subframe structure is unique in the polar regions.

CIB shall use a polar stereographic projection, in which

meridians (constant longitude) are plotted as radii emanating

from the poles, and parallels (constant latitude) are plotted as

concentric circles that are centered at the poles.

a. The north and south polar zones, 9 and J, are depicted

in FIGURE 15 and FIGURE 16 in the APPENDIX, Section A.3. These

zones are circular with the pole at the center and the radius

being the distance from the pole to approximately 80� (north or

south) latitude. The polar frame structure is square. The

center frame is positioned with the pole in the exact center of

that frame and the sides of the frame making right angles with

the 0�, 90�E, 180�W, and 90�W meridians. The origin for polar

zone frame rows and columns is the lower-left corner of the zone.

Polar CIB frames are not all oriented along the north-south and

east-west directions. Further detail on the frame structure and

orientation is provided in the APPENDIX, Section A.5.

b. The pixel coordinate system for polar zones is centered

at the pole. Polar zone pixels are transformed from (<X>, <Y>)

pixel row and column coordinates to latitude and longitude (φ, λ)

coordinates, as described in the APPENDIX, Section A.3. Pixel

resolutions and sizes are not constant in a left-right or up-down

direction. The number of pixels in the polar zone is adjusted so

that there are an even number of subframes centered about the

poles. There are an odd number of frames with symmetry about the

pole. The APPENDIX, Section A.5, provides calculations to

compute average frame pixel resolution.