How to use ESA's Eoli-sa to find and order scenes from ESA

Eoli-sa is a software client to read ESA's catalog, select scenes to order, prepare and make orders, and track orders. You can also use Eoli-sa to find information about ERS and Envisat scenes for uses other than ordering, such as preparing a list of scenes of interest.

Eoli-sa has a web site where you can get the software.

This web page by UNAVO is provisional as we learn to use Eoli-sa. We believe what is here is correct. If you find corrections send an email to wier@unavco.org

How to install and run Eoli-sa, and get the help document

Get the latest version of Eolisa (such as version 5.3.1 as of January 2008). Earlier versions will not work. See Download & Install EOLI-SA. Download the installer program for your computer, and follow the instructions.

To run Eoli-sa on Linux, find the "eolisa.jar" file and enter the command
java -Xmx1000m -jar eolisa.jar

Sometimes on my Linux system Eoli-sa freezes up (it uses 99.5 of the cpu and will not respond, and does not repaint its window after window moves). Be patient; it's busy. It will come back, but may take many minutes. You may be able to reduce or avoid this problem by increasing cache size with the main menu choice App->Preferences->Cache. Since I increased the cache to 100 MB the problem has not occured. You have to stop and restart Eolisa for the change in cache size to take effect.

How to select scenes for Envisat orders

Start Eolisa. Use the green "Connect" button to login. Anonymous logins allow selection of scenes and searching the ESA catalogs, which is what is described here. To place orders with ESA using Eolisa you will need a username and password provided to you by ESA (case sensitive). ESA will disconnect your session after a few minutes of non-use. Just reconnect; your menu choices should still be valid.

The example here is for selecting scenes for Envisat; ERS selections work similarly.

Click the far left box with the "+" by "On Line Collections" to see its list of categories. Click the box with the "+" left of "ENVISAT" to see it's list. Then for example, click box left of "ENVISAT ASAR" to see that list.

Select the kind of Envisat products you want. For interferometry check the Envisat "ASAR Image Mode" data. This is equivalent to single beam SAR data. The other product of potential interest is Envisat "ASAR Wide Swath" data which is multi-beam (ScanSAR). (One radar scientist says "InSAR does work with Wide Swath mode data, but it depends on the steepness of topography how well it works.") Click for example on the check box by "ASAR Image Mode," or on "ASAR Wide Swath."

Select "Query mode: Advanced."

Under "Date" use "Choose a Date," click the round "Date" button, and enter start and end dates for the search. Ignore "step by range."

Under "Area:" use "Area Selection." Click the round circle by "Cir" (circular area). Enter the latitude and longitude of your point of interest. Longitude west is negative such as -114, or an equivalent east longitude value, such as "243." You can enter decimal degrees, although the display shows minutes and seconds not decimal values. Enter a radius such as 600 [km]. Or you can choose a rectangular area with the "Rect" choice and a center latitude and longitude, and height and width in kilometers.

To see swaths click the "no frames" button. To choose frames click "show frames."

Click Pass Type "Ascending" or "Descending" or both.

You need not enter orbit or track number if you use an Area Selection.

To search the ESA catalog, click the red "Search catalogue" button on the lower border of the window.

A new small window appears titled something like "Search Results (377) items in total." Click the box next to one of the item number ranges, such as "from 1 to 100." Or click the left-most icon button just above autoload to choose all. Click the "Append" button." Those items (swaths or frames) are then added to the list, in the area under the map.

Eolisa allows you to work with at most about 2000 scenes at a time. If your selection process finds more than 2000, you will see a window that says, for example, "Too many hits found (2824); please narrow your search criteria." Often the best way to narrow the search is to use a shorter time interval.

To see the map of scenes' coverage, click on the Navigate button above the map, then on the button with the pop-up tool tip that says "Zoom the map to the current area." You can zoom out to see a larger area.

The scenes selected are those that just touch in any degree the search area specified. Click the "Set Area" or "Footprints" button to see the frame outlines.

Thumbnail pictures of the scene are shown in a stack to the right of the map. The pictures come from ESA; not all scenes have thumbnails.

Click on an item in the table to select it. Its footprint outline on the map turns green, and its thumbnail appears on the right of the map is outlined in green. For more than one, do CTRL-click on each additional item. To select all items in the list, use menu choice, on the top menu bar, "Result Set-> Select all." Selected items have their outline color on the map changed to green. To un-select all times, do menu choice "Result Set-> Clear results."

Swaths or frames?

Frames are scenes that are approximately square. Swaths are long narrow scenes made of a sequence of many adjacent frames. In the example here, the same search criteria found returned two lists of results: "no frames" gave 87 swaths, and "show frames" gave 356 frames, both covering the same area and radar data. Here is the map with footprints of the 356 frames, with a few selected in green. Compare it to the swath footprints shown above. Note that swaths are cut short to fit close to the selection area; Some "swaths" near the edge of the selection area are only one frame. If you want longer swaths; use a larger area radius or height and width. Eolisa appears to make swaths depending on your selection area.

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Data quality

Quality of data varies. How to select good quality or avoid the bad data I do not know yet. Please send word if you know.

To save selected items in a local file (formats are csv ("Excel"), XML, HTML, or "UserSet")

To save the selected items to a file on your computer, click on the "Press to export" buttton which looks like

In a new window you can save the data in 4 formats: cvs, XML, HTML, and "UserSet." The results are all single files for each format, except the HTML option.

The csv format file is a comma-separated-value format. If you click on the icon for such a file on a Windows system, Windows will say this is a "Microsoft Excel csv file." You can open it in Excel and it will load as an Excel document. On Linux you can do the same in Open Office. It is ASCII and can be read with any text editor or used in other programs that use csv files.

The XML file format has exactly the same data as the csv file, in xml.

The "UserSet" file name extension is .usr; it is an ASCII file, with one line per scene, and with "|" as the field separator which makes a slightly more compact form than the .csv file. It has the same data values as the csv and XML files.

The "html" option makes an HTML file (with new subdirectory or "folder" on Windows), with map imagery and a web page of data, and the preview thumbnails. Look for a file called htmlExport.html and a bunch of image files on a non-Windows system.

To put selected items in an order

for now, see the Eoli-sa Help document ..

Last update 28/2/2008
Stuart Wier, UNAVCO