There is a slight misalignment between the pop density and the urban extent data layers for Africa, due to differences in the BLW files. The former layer has 0.00833333333330 0.00000000000000 0.00000000000000<br/><br/> -0.00833333333330 -25.99583333333335 37.99583333303735<br/><br/>and the latter has<br/><br/> 0.00833333000000<br/><br/> 0.00000000000000<br/><br/> 0.00000000000000<br/><br/> -0.00833333000000<br/><br/> -25.99583333500000<br/><br/> 37.99580373499999<br/><br/> <br/><br/>This makes a difference of a couple of hundred meters. Is this just because the analysts were rounding? Is it okay to use the same BLW data for both files?

It should be no problem to use the same .blw for the two files, the difference is just noise (much less than the locational accuracy of the dataset). The difference is simply a matter of precision — the grids were created with the environment set to double precision, while the extent layer was created with an environment setting of single precision.

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