Getting Started with
the Datacasting Feed Reader
The Datacasting Feed Reader is an application used to subscribe and
read RSS 2.0 and Datacasting feeds. This feed reader allows you
to take advantage of the unique metadata included with datacasting
feeds.Subscribing to Feeds
In order to subscribe to a Datacasting feed, you must first find a feed to subscribe to. If you haven't got a feed in mind, just click through the Getting Started tab in the Feed Reader and select the Datacasting Feed Directory link.
This will open a web browser window and
bring you to our online directory. From there you can add a
feed. Let's choose the "QuikSCAT hurricane data" feed under
"Phenomenon".
Now right-click on the link to the feed and copy the link into your clipboard.
Next, return to the Datacasting Feed Reader and click on the Add button
You are now subscribed to the GHRSST-L4 Hurricane Sea Surface Temp feed. Your reader will now occasionally check and automatically collect any new articles posted to this feed.
You can also search Google for Datacasting Feeds, or request that your favorite data provider start providing a Datacasting Feed.
Now right-click on the link to the feed and copy the link into your clipboard.
Next, return to the Datacasting Feed Reader and click on the Add button
You are now subscribed to the GHRSST-L4 Hurricane Sea Surface Temp feed. Your reader will now occasionally check and automatically collect any new articles posted to this feed.
You can also search Google for Datacasting Feeds, or request that your favorite data provider start providing a Datacasting Feed.
Viewing Feeds
Now the feed name should be displayed in the upper left panel and a list of articles should appear in the upper right panel. You can select one of the articles and in the Standard View tab you should see something like this:
A preview of the granule region is shown in the bottom left (if available), and all of the metadata concerning this data granule is displayed to the right.
You can see an image preview of the data (if available) by choosing the Image Preview tab in the bottom left. You can view the preview more closely by double-clicking on the image. More options are available in the preview window with a right-click.
You can also customize the column view in the article list by selecting Options -> Customize Column View... Try adding the wind speed column.
Now sort by descending wind speed by
clicking on the column header twice...
You may even rearrange the columns by dragging the column heading. All of the information described in the article view is available to be added as a column. The information is stored in XML tags and each tag has an easy to read long name in the article view.
All of the tags are also available for filtering as described in the next section.
Filtering Feeds
The most powerful aspect of the Datacasting Feed Reader is that of
filtering. Filtering allows you to select articles from a feed
based
on the values of the metadata stored in the feed. In order to
create a filter, right-click on the feed you wish to filter.
For example we'll create a filter which selects all data with Acquisition Start Time after August 8th, 2010 (2010-08-08 00:00:00 GMT) and with Hurricane Max Wind Speed greater than 60 knots.
As you can see, this filter collects 8 articles that match the criteria in this case (your results may vary if new hurricane data has been added).
You can filter any feed or add a filter to further constrain an existing filter (see below). When specifying a filter, you can choose to "Flag on match" or "Download on match". These will be described in greater detail below.
Flag on Match
Flagging articles marks them for future attention. It is a way of reminding you that you think that it might be important. One way of flagging articles is to simply click in the flagging column of the article that interests you.
You can also flag articles using a filter and the Flag on match check-box. We'll create another filter which is nested within the After 8/8/2010 & > 60 kt Winds filter to further constrain wind speed and only select those articles with less than 70 knot winds and we'll mark these with a flag. In order to create this nested filter just right on the parent filter and only those items which are selected by the parent will be furthered constrained by the nested filter.
These articles are flagged in any view. Even when they are mixed in with other articles.
Editing Filters
Editing filters works just like creating them. You simply right-click on the filter and select Edit Filter. If, for instance, we are only interested in storms in a specific region of the Atlantic, we can create a spatial criterion based on the Location tag.
After clicking on the Via Map button we can select a point-radius region on the map, and then we click Ok.
Optionally, we can enter a percentage of area overlap between the data region and the filter region, and then we click Apply Changes.
The resulting filter only selects a single storm, IGOR. This storm matches all of our nested criteria and is flagged.
Based on reading the data provider's website, we find that the Hurricane Identifier contains "L" whenever a storm originates in the North Atlantic basin, so we could have filtered based on the Hurricane Identifier tag instead of the Location tag.
Downloading
Once you have identified data of interest, you will likely want to download it. There are a number of ways to download data including using a filter, but Download on Match will be covered later. If you have an article of interest selected, you can select Download enclosure from the Articles menu.
Also, clicking the check mark column in the article list will download the enclosure. This column also indicates the state of the download; a check in the column means that the data has been downloaded, a running dog indicated that the data is being downloaded (fetched), and an X indicates that the download is incomplete (canceled or failed).
You can check up on the download progress by looking at the Download Manager by going to Options -> Show download queue... This window shows you all on-going, completed, failed, or canceled downloads. In this case, it shows that we successfully downloaded a data granule.
Once files are downloaded, they are stored in the subdirectory download in the directory that you ran the FeedReader.jar from.
The subdirectory names are formed from the feed name, year, and month/day that the data granule was published.
