HI Jim,They really aren't duplicates. In order to fit the Extreme Landscapes on three CDs, some of the flatter areas were recompiled at 76.4m, thus significantly reducing file size, since predominantly-flat areas really don't show very significant improvement going from 76.4m to 38.2m resolution anyway.So, looking at my file-naming conventions, you can see that one file is 38m resolution and the other is 76m resolution.Since we are talking relatively little disk space savings, nothing is hurt by leaving the 76m files there. The simulator will automatically display the file with higher resolution. Hope this helps-------Justinhttp://www.fsgenesis.netHigh Quality Scenery for FS200x

Thanks for the info Justin. I'm no longer confused. Thanks too for your contributions to flight simming. You help make it much more enjoyable for all.Jim Young

>>imagine all the misaligned airports and lakes 76m accuracy>would create!I think you misunderstood what 76 meter stands for. It is the accuracy of sampling data (in elevation). It can't possibly cause "misaligned" lakes or airports. The worst it can cause is smoothing of abrupt elevation changes. Michael J.

>So the 9.6M refers to the distance between the points in the>mesh im meters? I doubt, though, that it refers to all three>axes (x,y,z), but only to the x and y values. The Z component>is the Elevation Data of a certain point, so 76 meters>accuracy in the horizontal axis would be very bad! Just>imagine all the misaligned airports and lakes 76m accuracy>would create!>>Can a mesh designer tell us how accurate the elevation data>is?>>ClaudioCorrect Claud, Just the X and Y values, FS will do precise to the foot as per the Z value.

Yup, I have most of Justin's offerings via payware and am extremely pleased with them. His Australian data has completely transformed my simming experience in my home environment.Thanks Justin,Chris Porter:-outtaPerthWestern AustraliaMy "Around the World 4" flight pagehttp://members.iinet.net.au/~portercbp/fly...e%20World_5.htm