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2.2  Searching the Web Portals

Finding, collecting and downloading paleomagnetic and rock magnetic data from the MagIC Database is important for most users. In this Chapter we explain the different search functionalities you can find on the MagIC Home Page and in its Search Portals. For more detailed information on searching we refer to the Online MagIC Help Library at http://earthref.org/MAGIC/help.htm.

2.2.1  MagIC Website Home Page

Start by visiting the http://earthref.org/MAGIC home page, from where you can launch the PMAG and RMAG search portals, manage your own contributions, find important web links, a list of the most recent contributions, and read the latest news about paleo and rock magnetism.

2.2.2  The PMAG Portal

The PMAG and RMAG web portals form separate entry points for paleo and rock magnetic searching. Although you can carry out different kind of searching, both portals interrogate the same underlying EarthRef.org and MagIC Databases. For this reason, you can find rock magnetic data when searching in the PMAG Portal and paleomagnetic data when searching in the RMAG Portal. The portals merely are different starting points that are tailored to the needs of either magnetic community.

Below, we show you the resulting Measurement List from a particular drill down search in the PMAG Portal. As can been seen from this example, we drilled down from McMurdo to the actual measurements on Specimen mc01a. In this view of the data you can link back to the Tauxe et al. 2004 paper in the EarthRef.org Reference Database, you can use the links in the upper left of this listing to navigate back through your drill down history, and you can use the Save, Plot and Options pull down menus for more advanced functionality.

Note that the Units of the data are given between brackets in the Header of this table. All units are SI based, except for some fields, such as geological age. If you mouse over the headers, a longer explanation is given in a popup balloon. If you mouse over any of the cells in the table, a similar popup balloon is shown that contains the header information, as well as the basic information that is displayed in the left most column (experiment info in this example). This functionality will help you to better navigate larger data tables or when you show the table in Expanded View (see below).

In the above example only data from the Basic View is shown. You can select the Expanded View from the links to the upper left. If you do so, all available data for each particular measurement are shown. In the near future you will have the ability to set your own Search Preferences, in which you can predefine what columns are shown in both the Basic and Expanded Views, and in what units you want to view your search results. For example, you will be able to set your preferences to always show ages in Ma and paleointensities in µT instead of the default T.

Searching by Location

In the PMAG Portal one can search by location, which allows you to drill down from any location to the actual measurement data. You can do so by providing a lat-lon box, keywords to find a certain location by name, the last name of the first author, or a combination of these searches. You can also perform a map search by clicking on the Map Search button.

Searching by Reference

Searches by reference will provide you with a Detailed Reference Information table (see below) for a given publication. From this table you can view and download various Background Data Files, including the Microsoft Excel© and text versions of the MagIC SmartBooks. This table also provides Quick Links to the MagIC and other EarthRef.org databases, when these exist. In addition, a link may appear to the Provider of the publication, which redirects you to the Full Length HTML version of the paper on the publishers website. From here you can download a PDF of the publication, provided you or your institution has access to the journal or publication in question.

Advanced Searching

In the PMAG Portal you can also perform a more advanced search, which allows you to combine various Boolean searches terms. These terms normally are an accumulation of all other standard searches. You can also perform a map search by clicking on the Map Search button.

2.2.4  Plotting and Visualizations

Many Plotting and Visualization options are available through the Plot menu. In the plots and maps that you can generate at the MagIC Website all data from a single results table are included. If a results page contains more than one table, you can always Group Together the tables and make a new plot with all combined data. All plots can be saved as PNG (image) or SVG (scalable vector graphics).

These plotting tools will be expanded considerably in the future, allowing different kinds of experiments and data to be plotted, such as Rock Magnetic measurement plots (hysteresis loops, FORC diagrams, etc) and Stratigraphic Section and Drill Core plots. The ultimate goal is to make these plots and maps of good publication quality, to deliver them as SVG (already available), and to make the plotting more interactive so that you can access the results of different averaging scheme's or data selections.

Global Maps and Orthographic Projections

On the Location, Site, Sample, Specimen and Measurement levels you can generate maps that plot their latitude-longitude positions. Global Maps (see the image above) are available as well as Orthographic Projections (below) in order to view data around the poles. Both map views are combined with an Equal Area plot.

Paleomagnetic Plots

On the Measurement level you can plot various other diagrams, such as typical Zijderveld, Thellier and Arai plots. These plots (see below and next page for some examples) are drawn from the data residing in the database and provide a good view of the data itself and the quality of the experiments carried out.