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

3.5.1 Scale and Pixel spacing. In the nonpolar zones,

pixel spacing is the nominal ground sample distance (GSD) of the

source image, at nadir, in both the east-west and north-south

directions on the WGS 84 ellipsoid. In the polar zones, pixel

spacing is the minimal GSD of the source image at nadir in both X

and Y axes of the polar stereographic projection. A nominal

scale for CIB can be calculated for comparison to National

Imagery and Mapping Agency ARC Digitized Raster Graphics (MIL-

PRF-89007) or Compressed ARC Digitized Raster Graphics (CADRG)

(MIL-PRF-89038) by using the following equations:

CIB scale (Compared to ADRG)= 100 x 10-6 / GSD

(1)

CIB scale (Compared to CADRG) = 150 x 10-6 / GSD

(2)

a. In the above equations, the "nnn x 10-6" value

corresponds to the distance in meters between the pixels that are

scanned on the paper map for the ADRG or CADRG product (100

microns and 150 microns, respectively). Dividing this value by

the distance in meters between the samples on the ground (GSD)

for the CIB product gives the equivalent scale for CIB. As an

example, in a 10m CIB product, the equivalent scale as compared

to ADRG is 100 x 10-6 / 10 or 1:100,000.

b. Within a non polar zone, pixel spacing is fixed in units

of arc-seconds of latitude per pixel and arc-seconds of longitude

per pixel.

c. The numbers of CIB pixels in both latitudinal and

longitudinal directions shall be adjusted so that there are

integral numbers of subframes per zone. In the polar zone, the

number of CIB pixels is adjusted so that there is an even number

of subframes across the zone in each dimension.

3.5.2

Frame and subframe tiling.

a. Each frame shall comprise a rectangular array of 1536 by

1536 pixels (2,359,296 pixels). Each frame shall be tiled into a

grid of 6 by 6 subframes (i.e., 36 subframes) Each subframe

shall comprise a rectangular array of 256 by 256 output pixels.

Subframes shall be numbered (0...35) as depicted in FIGURE 2, in

accordance with MIL-STD-2411.

b. All frames and subframes within a zone shall abut in a

mutually exclusive manner without any pixel overlap or pixel

redundancy, except as noted in 3.5.4b. The distance between a

pixel that falls on a frame or subframe border and its neighbor

in the adjacent frame or subframe shall equal the GSD for the

product. The northern and southern boundaries of a zone

generally will not fall exactly on the northern and southern

boundaries of a frame or subframe. There shall be frame overlap

between the zones, as defined in 3.5.5.