A few days ago I downloaded the NLCD 2006 landcover database from this site:
http://www.mrlc.gov/nlcd06_data.php
I was able to view an image of the data in GM, but couldn't extract any of the data. When I dragged my cursor over the colored portion of the image, GM reported PAL IDX 0, and RGB(0,0,0). Also, when I zoomed in to the image eventually it went black, but I could zoom out and the color returned.
I reported this to Mike, who tested it at GM and who had no problem opening the file, but couldn't suggest any reason I couldn't open it. From this I conclude there must be something weird on my local PC.
Later I obtained the same file as a GeoTIFF and GM opened it fine (using only 36% of my available memory), so I don't think my available memory was the problem.
My system is has an i7 processor and 8 GB RAM, and I'm running Win7-64.
I'd appreciate any suggestions.
I can not offer any suggestions on your problem; however, I downloaded the 2006 in August from the USGS seamless server and did not have any issues with GM.
I found I could access the data if I extracted the IMG, RRD, and IGE files from the zip and opened the IMG file. Apparently the IMG (23KB) references the data (16GB).
Quote from: maps4gps on October 15, 2011, 03:04:11 AM
I downloaded the 2006 in August from the USGS seamless server and did not have any issues with GM.
Did you get the file as a geotiff, or an ERDAS zip file? I don't have any problems with geotiffs.
As geotiffs. in 2x3 degree files, each specified individually (138 files totaling 1.47 Gb)
Mike's fixed the problem with ERDAS files now. Problem had to do with unzipping the IGE file.