In addition to the one-dimensional, narrowband infrared data generated by the DARPA Background Mea-surements Program (BMP), collateral two-dimensional visible light data were also obtained. System designs require two-dimensional background models, but in the absence of the requisite data, isotropy has been assumed to exist in the backgrounds, so that the one-dimensional BMP infrared data can be utilized directly. We test the validity of this critical assumption for a variety of background types. The scenes along the aircraft flight paths in several visible light data frames have been scanned and digitized for comparison with the infrared radiance scans. To the extent that the visible light and infrared data correlate along one dimension, the degree of anisotropy measured in the visible light data is inferred to apply to the infrared data also. Sample scenes exhibiting two-dimensional anisotropy are presented.