OverviewThe eoPortal Catalogue Client gives access provides information on EO products of many data providers like ESA, DLR, and NASA. With the eoPortal Catalogue Client you can search for EO products, get a brief description of their characteristics, and see a quick-look of many images. It is also possible to retrieve full details of a product, which contains information on how to order the product.
Starting the eoPortal Catalogue ClientThe eoPortal Catalogue Client can be found at http://catalogues.eoportal.org/eoli.html. When you first start the client you should see a page like this:
If you do not see this page, or only part of it (e.g. the globe is missing) you may need to install the Sun Java plugin and/or configure your browser to make it your default Java Virtual Machine; see here for instructions.
Product searchThe tab that is selected by default is Find Products. To do a product search, first one or more collections must be selected and the standard criteria Date and Area need to be supplied. Below you can find the details on how to do this, but if you know it already just turn to the section Submit query.
Collections (upper-left panel)The collections panel is composed of a tree containing all dataholdings of the various data providers. A tree branch can be unfolded by clicking on the '+' icon in front of the collection name, and folded again by clicking on the '-' icon. Selection of a collection is done by checking the box in front of a collection name, deselection is done by clearing it. Checking the box of a non-leaf collection selects all leaf collections below it, but note that only a limited number of collections can be searched simultaneously. The number of collections selected is displayed above the tree, where you can also find an icon to deselect all collections, and an icon to (un)fold the entire collections tree. If you have no idea which collection(s) to select, you can click on any name in the tree to get an overview of the characteristics of that collection. Or you may want to do a collection search first.
Date (center-left panel)The Date criteria can be set in various ways. The most straightforward method is to fill out the From and To boxes using the format that is displayed by default. Alternatively, clicking on the arrow in these boxes brings up a calendar on which you can select day, month, and year. Select the date displayed by the calendar by clicking on the Apply button, or cancel it by clicking anywhere outside the calendar pop-up. The third method to specify a date is by selecting one of the predefined periods from the Choose a Date dropdown list.
Once a date range has been specified it can be shifted using the Step by range dropdown list and associated arrows. For example, by selecting Step by month from the dropdown list and clicking twice on the left arrow, both the From date and the To date will be anticipated 2 months.
Area (center-left panel, upper-right panel)The Area to be searched can be set in two ways: either you fill the Center Lat/Lon and Extension Lat/Lon boxes, or you use the map applet (i.e. the globe) on the upper-right panel to do so. Since the coordinate system units are degrees the latitude specified must lie between -90 and 90, while the longitude must lie between -180 and 180; obviously also the latitude extension is limited to a value between 0 and 180, and the longitude extension to 0 and 360.
To select a rectangle using the map, select the Set Area radiobutton, click - and don't release - on the globe to select the first corner, then move the mousepointer and release it to select the second corner. However, you may want to move the globe or zoom in first. To do so, select the Navigate radiobutton and click anywhere on the globe to reposition the center. Or define a rectangle as described before to show only that part of the world and zoom in on it. Or use the right/left arrow to zoom in/out on the globe's center. Or use any combination of the above methods to get where you want. You can always go back to the default globe by clicking on the mini-globe icon above the map. And if you don't like the colours of the default map, you can click on the Map Layers button to give it a different look (at the expense of some rendering speed though). Finally, note that it is possible to increase the size of the globe by dragging the horizontal separator bar just below the map panel downwards.
Advanced Criteria (lower-left panel)If you are not satisfied with the Collection, Date and Area criteria you can switch to the Advanced criteria by choosing that option from the Query Mode drowdown list, provided only a single collection has been selected. The additional criteria this mode currently offers are DateTime (instead of Date), Track (instead of Area), and MaximumCloudCover. If you want to increase the space dedicated to the Advanced Criteria panel, drag the horizonal separator between this panel and the Date/Area panel upwards (you may also want to drag the horizontal separator between the Date/Area panel and the Collections panel upwards).
The DateTime criteria can be specified by selecting the DateTime radiobutton on the Date/DateTime panel. It is identical to the Date criteria except that it also allows the specification of the From and To time. To this end the calendar pop-up has some extra buttons, which are self-explaining.
The Track criteria can be defined via the Track radiobutton on the Area/Track panel. It allows you to search for products captured by the satellite's sensor while following a certain track. It takes too far to explain the track concept in this tutorial, and if you choose to use it you probably know already what you are doing.
Help, preview collection details, or population statisticsYou can find out more about a collection and the products is contains by choosing one of the options from the Preview dropdown list. If no or multiple collections have been selected only the Help option is available, which brings up this tutorial. If exactly one collection has been selected, however, you can choose to get a pop-up window with the collection's details or its population statistics. The collection details tell you more about the collection's spatial and temporal coverage, theme keywords, possible contact persons, etc, while the population statistics show you how many products are available for a number of discrete periods, and in some cases also which part of the world is covered by these products. This way you can more effectively specify the spatial and temporal coverage used with your product search.
Collection searchIf you don't know which collection to search for products, you may want to do a collection search first. A collection search follows the same mechanism as the product search described before, but the result is not a set of products but a set of collections that can be used for subsequent a product search.
To switch from product search to collection search, click on the Find Collections tab on the upper-right panel. Instead of a Collections tree the upper-left panel now contains a Disciplines tree, and a Free text search box has been added to the Standard Criteria panel (lower-left). You can fold and unfold the tree in exactly the same manner, and selection of disciplines is identical as well. The only difference is that aggregation of disciplines takes place, i.e. selecting all child disciplines of a parent discipline makes that the parent discipline itself will be selected. In general this will result in more hits because searching for e.g. discipline Agriculture > Agricultural Aquatic Sciences will match a collection having discipline Agriculture > Agricultural Aquatic Sciences > Aquaculture, but a search for Agriculture > Agricultural Aquatic Sciences > Aquaculture will not match a collection having discipline Agriculture > Agricultural Aquatic Sciences. If you specify several disciplines, the collections that will match contain at least one but not necessarily all of them. Note that there is a maximum number of disciplines that can be searched simultaneously.
Apart from selecting one or more disciplines, you must also specify Date and Area. If the Free text box is filled out, however, discipline selection may be omitted. The string supplied for free-text searching must appear as a whole anywhere in - certain fields (e.g. Abstract) of - the collection descriptor; matching will be done in a case-insensitive manner.
At any time you can switch to Advanced criteria by selecting that option from the Query Mode drowdown list. The additional criteria this mode currently offers are DateTime (instead of Date), MissionId, and SensorId. The MissionId criteria allows you to specify the satellite that carried the sensor (SensorId) with which the product was captured. When specifying both MissionId and SensorId, you need to a choose valid combination, e.g. the ENVISAT satellite does not carry the TM sensor therefore this combination will always return 0 hits. It is possible to make multiple selections as well as undo a selection as described in the section Look-and-feel of multi-selection dropdown lists.
Look-and-feel of multi-selection dropdown listsThe eoPortal Catalogue Client uses the standard Microsoft way to select multiple options from a dropdown list like MissionId. To select a range of options, click on the first option, use the slidebar to display the last option, hold the Shift key and click on this last option (you can release the Shift key now). You will see that all options between the first and the last selected will become blue to indicate that they belong to the current selection. To add or remove options from this selection, hold down the Ctrl key and click on the option to be added or removed (and release the Ctrl key). The entire selection is replaced by a single option if you click on an option and do not hold the Shift or Ctrl key. You can clear the entire selection by first selecting a single option only, then hold down the Ctrl key and click on that option again to remove it.
Submit queryOnce you have filled out all mandatory criteria, you can submit your query by clicking on the Submit Query icon at the bottom-left of the applet window. This will bring up a small status window in which the progress of your search is reported. At any time you can abort your search by clicking on the Stop button; clicking on the Close button closes the window but does not abort your search.
Once the search has finished and results have been found, you can check one or more sets of products to be presented.
To retrieve the results click on the Append button to add them after the results of previous searches, or click on Replace to discard all previous results.
View resultsThe results retrieved are displayed in the results table on the lower-right panel. A small number of fields are displayed including rownumber, item id or name, start date, end date. In addition each row has a Display checkbox, which determines whether or not the spatial coverage of the result is displayed on the map. Just below the results table you can find another Display checkbox; by first selecting a number of results and then checking or unchecking this box, you can manipulate the individual Display checkboxes of all selected results at the same time.
Selection of results from the results table is done by the same mechanism as described in the section on the Look-and-feel of multi-selection dropdown lists. Alternatively you can select a result by clicking on one of the thumbnails that are displayed in the vertical thumbnail strip on the right of the applet window. Or you can select a result by clicking on its footprint shown on the map . currently selected results are displayed in green, others in red - provided you selected the Footprints (or Navigate) radiobutton just above the map before. Lastly, the two icons with a blue arrow just below the results table can be helpful for the selection task: the left icon selects results in the results table, while the right icon inverts your current selection.
In case you did a collection search and the results table contains matching collections, an Add Results button (not displayed here) will be present and clickable if one or more collections have been selected. Clicking on this button will check the selected collections in the collection tree for subsequent product searches, which can be seen by switching to the Find Products tab.
It is possible to see full details of a product or collection by selecting a single result and click on the magnify icon just below the results table. This will open a new window in which many more fields describing the result are displayed. It may also display the product's quick-look, which is a low resolution image similar to but more detailed than the thumbnail image, which gives a good impression of the product. The quick-look can be manipulated (stretching and/or contrast enhancement) by clicking on the Image Correction button at the bottom.
The product details in general do not contain information on how to order the product or access it. However, this information often can be found in the description of the collection that contains the product. To this end the collection name (in this example ESA_ENVISAT ASAR Global Monitoring striplines) has been made clickable and leads you directly to the collection details of the parent collection.