Frequently Asked Questions



Main Categories

General

Q. I have registered successfully and been given a username and password, why can't I login?

A. Your information has been submitted to the Image2000 team for approval. This is normally done within one to two working days. Please be patient, but if you cannot access the service after this time, please contact us.

Q. Why do I have to be registered?

A. Registration allows us to monitor how the Image2000 data are being used. Spending a few minutes to register with us means that we have the necessary information to authorise you to use the data according to the Terms and Conditions.

Q. I have forgotten my password. What should I do?

A. Please email us and we will send you your password.

Q. The site is unavailable or there are problems with the map. What is happening?

A. This service is under development and therefore may not be available 24 hours a day, 7 days a week. We will of course endeavour to limit any downtime as far as possible. We are also experiencing very heavy traffic on the site, which is encouraging but which we are also working hard to manage properly.

Download

Q. All files have the extension .gz. What is this and how can I use it?

A. Files have been compressed (to minimize download times and storage space) using the gzip (GNU zip) utility. Winzip includes the gzip compression code and can be used to extract gzip compressed files. For more information on gzip, visit www.gzip.org. A single gzip file contains a "tar" (Tape ARchive) file which holds the five files required for each image scene.


Q. What is the convention used for naming the files?

A. The archive currently consists of so-called Product 1. These are individual Landsat scenes (defined by the path/row system of Landsat), which have been geo-referenced and ortho-corrected, by technical teams working in each country. Thus, the prefix of the filename SE12_195014 is broken down as follows : SE = 2 character ISO Country Code (in this case, Sweden) 12 = our internal unique serial number for that country. 195014 = the path/row of the Landsat orbit system

Q. Once I have extracted the files, I get  several file types associated with the same file name. What are these for?

A. For each scene, there are five files which must be downloaded. For the scenes SE12_195014 they would be as follows :     Se12_195014.bsQ.gz ? the image data, stored in a Band SeQuential (BSQ) format.     Se12_195014.bqw.gz ? the image world file, which defines the pixel size and origin coordinates.     Se12_195014.hdr.gz ? the image header file, which describes the structure of the image data.     Se12_195014.prj.gz ? the projection file, giving information on the map projection and coordinate reference system used for the image.     Se12_195014.mta.gz ? a simple metadata file, which for the time being contains simply the image acquisition date. Note that the first three files are mandatory in order to be able to display the data correctly in most systems which support the bsq format. Header, world file and projection information are formatted so that they can be used directly in ESRI software ? other systems may require re-formatting of this information.


Q. I have extracted the files for a given scene, and the main image file is in a BSQ format. What is this, and how can I use it?

A. BSQ stands for Band Sequential. The Band Sequential format is supported by many GIS and Image processing software packages, and is the standard format used for exporting multi-band data from the Land Management Unit's database. You can view BSQ files directly in the ViewFinder software which can be downloaded from the Leica Geosystems web site. Alternatively, the MultiSpec software from the Purdue Research Foundation will allow you to open the BSQ and then export into TIFF format.

Q. The file .prj contains projection information. What is the structure of this file?

A. The .prj file contains a text description of a coordinate system, in the OpenGIS Well-Known Text (WKT) format. This format is directly supported by ESRI ArcGIS (it differs from the proprietary structure used by earlier versions of ESRI software). Note that even in ArcGIS you will have to select this file in ArcCatalog as the Spatial Reference for each image you download.


Q. I can open the bsq file, but the image displays using pixel, not real-world coordinates. Why is this?

A. The world file (.bqw extension), is necessary to define the image to world coordinate transformation ? make sure this file is present with the same file prefix as your image in the same directory.

Q. I am interested in only a small area ? can I select and download a subscene?

A. No. At the present time, only entire scenes can be downloaded. A mosaic product is in preparation which in the future will support selection by user-defined rectangle.


Q. Some scenes with the same path/row and the same data are available from different countries. Why is this, and what is the difference?

A. Landsat orbit paths do not respect any national boundaries. Thus, in the extreme case of Luxembourg for example, you find that the same path/row covers the territory of Luxembourg, Belgium, France, Holland, Germany. The same image was supplied to these 5 countries, each of whom corrected the image according to their own national map projection and available Digital Elevation Model.

Q. The FTP connection sometimes breaks during a download ? do I have to download the entire file again?

A. Unfortunately, interruptions can occur. To avoid wasted download time, select an ftp client which supports automatic reconnection after interrupted transfers.

Q. I cannot access the FTP site for download. Why is this?

A. In order to limit traffic on our server, it is currently set to a maximum number of 10 concurrent users. Please try later to download files.

Product Questions

Q. Where can I find out more information on how the Image2000 products were generated?

A. More information about Landsat, the satellite system providing the base data, can be obtained from the Landsat 7 Project Home page at USGS. For information on how these data were acquired and made into the various product types of Image2000, see the Product Characteristics page on this site.

Q. I see there is a European Mosaic. Can I download this?

A. Not at the current time. You can view the panchromatic mosaic here. In the near future, we hope to have the individual tiles that make up this mosaic available for download, as well as a service and download for the multispectral mosaic.

Q. Can I pass the data to anyone else?

A. Absolutely not. The data are provided to you as a registered user. Even if an immediate colleague wishes to use the data, they should register also and request the imagery. Any circulation of the data is prohibited by the terms and conditions, and remember that these data are strictly for non-commercial uses.