On the seamless USGS site I can download the ArcData just fine but cannot modify my request to download the .BILs... is anyone else having the same problem?ThanksJohn

Hi John,I find that sometimes I have to run the process twice in a row to have the website switch from ArcData to the format (or data type) I want. Have you tried that? Cheers, Holger

I did try it twice in a row with the same error message.Now the site is acting up on my computer, taking forever to load. I still have the error, but I bookmarked the page and am trying again later.On a different topic, which type would be the best to download if you are looking to make LOD12/13 mesh scenery? SRTM 1 or Ned 1:1/3?

Howdy,good luck with the USGS site!The highest mesh resolution FS9 can display is LOD11 (19m, with TMVL set to 21).You can't really compare the SRTM 1-arcsec data to the US NED 1/3-arcsec data because of the big difference in resolution. Generally speaking, for most areas in the US the NED data are more accurate than the SRTM 1-arcsec data. However, 1/3-arcsec NED source files will be approx. nine times larger than the SRTM1 data, which is something to consider if your project area is fairly large.Cheers, Holger

Size shouldn't be a problem, thanks. I'm doing about a 0.5x0.5 square degree project (which I will be announcing the details of shortly!).However, I still cannot get the site to work correctly, despite bookmarking the page and trying back repeatedly.