Q: Why do I get an error when trying to click on the
link to access ESDI?
A: This is usually caused by a firewall on your end
rejecting outgoing connections on port 8080. Contact your local system
administrator to see if connections to this port are not allowed. This
can also occur if our application server fails.
Q: Do I have to use ESDI to download your data?A: No, you can access the FTP servers directly
at ftp://ftp.glcf.umiacs.umd.edu.
Landsat is stored in the glcf/Landsat directory. You can also
download ESDI layers for searching in your own
GIS application.
Q: I'm looking a specific scene and I can't find it in ESDI
or on your web pages. Do you have it? Can you upload it for me?
A: No. All data that we add to our archive are obtained
through free sources or from data donations.
Q: All files I download end with a .gz extension.
What does .gz mean?
A: Files that end with a .gz extension have been
compressed using GNU zip and must be uncompressed. For Windows,
use WinZip,
for UNIX use gzip,
and for Mac use
Stuffit Expander.
Q: When I try to download a data file, why does it
dump the file out as text in the browser window instead of saving
it to my hard drive?
A: This usually happens with files that have
been compressed with gzip (.gz file extension). If this happens,
your browser isn't configured to handle that file type and uses
ASCII mode for downloads by default. You can either right click on the link
(or relevant operation on non-Windows platforms) and choose "Save As..."
or add a new MIME-type in your browser settings to recognize
gzip files. The MIME-type should be listed as
application/x-zip-compressed
for suffixes with gz.
Q: I downloaded a gzip file, but why is the .gz
extension missing?
A: Your browser or FTP client automatically
uncompressed the file for you. The data file is now ready for use.
Q: I have no problems using ESDI, but I am having
problems when downloading the data files. Any suggestions?
A: If you are behind a firewall, your
Web browser or FTP client must support and be configured to use
passive transfer mode. Most modern versions should switch to this mode
automatically but some versions of Internet Explorer require you to turn
this mode on under "Internet Options". If you are on a slow connection, try
using an FTP client instead of your web browser to download the files or
automating your downloads. When clicking
on a scene in the "Preview & Download" screen, a link to the FTP directory
is available. Use that link in your FTP client. Our FTP servers support
resumable transfers, so use an FTP client that supports this feature.
You can also try downloading during non-peak hours
(anytime on the weekends or 03:00 UTC to
10:00 UTC on the weekdays).
Q: I am using ArcView, how do I import your imagery?
A: See the
File Format Guide.
Q: I am using ArcInfo, how do I import your imagery?
A: See the
File Format Guide.
Q: Any tips on importing your imagery into other programs?
A: GeoTIFF files should not present a problem since
all the information is embedded in the image header. For the binary
files, look for a way to import raw, raster, or binary files. You will
need to supply the image dimensions which should be found in the metadata
file provided.
Q: My connection is too slow to download the data files.
Can I have the files put on media and shipped to me instead?
A: Our data is always free for download, but
we can send ship a copy to you for a fee. In most cases, this
remains a cost effective solution. Contact us for pricing information.
Q: I've downloaded a data file but why does my computer
tell me that it has a virus?
A: Certain virus protection programs
falsely indicate that our data files have viruses. For viruses to work,
they need run a program by either embedding themselves in other programs,
by disguising themselves as a legitimate program, or by overflowing buffers
or stacks using known faults in specific programs. Since the data files
are not programs and do not disguise themselves as programs, the
actual chance of this file containing a virus is extremely low.
There is also a chance that the file was corrupted in transit, and
while not infected, was flagged as containing a virus. Try downloading
the file again. If you
think you have downloaded a virus in one of our data files, we can
verify the contents of the data on our servers for you. If you
still do not feel comfortable using that data, you may discard it.
Q: You provide a great service to the Earth Science
community, is there any way I can contribute?
A: If you have data that we do not have, you can always
donate a copy to us and we will make it available for everyone to download.
You can also help by sending us any comments or feedback.
We rely on this feedback to improve the services that we provide.
Contact us for more information
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