Final calibration factors were not applied to the third sky coverage data before production of the photo products. Therefore, the intensities obtained using the procedure above on the third coverage may not agree with intensities found on the magnetic tape versions of the maps. The magnetic tape version uses the final IRAS catalog calibration and should be used in case of discrepancy. The first, second and mini-survey coverage photos were corrected to the final calibration. In this orientation the horizontal rows of pixels are by convention called lines and the pixels within each line are called samples.
Line numbers increase from top to bottom and sample numbers increase from left to right.
With this information and the tic marks along the sides of the image area the line and sample coordinates of any pixel can be determined for application of the inverse map projection formulae given above in Section X.D.2. The tic marks also allow alignment of the coordinate overlay grids as described in Section X.D.7. These color versions of the data are not intended for quantitative analysis. The shift and scale information in the label is difficult to read and no attempt has been made to produce a consistent color balance among the plates. See maps in fig.