Mantle temperature: click for full size

Table of Contents for GEON IDV web site Introducing the GEON IDV GEON IDV: Data Displays & Analysis Capabilities     GPS Velocity Vectors & Error Elipses     Earthquake Locations and Magnitude     Earthquake Focal Mechanisms     Seismic Anisotropy     Seismic Tomography     REM Global Seismic Tomography Data     Topography Data and 3D Relief Maps     Yellowstone Geophysics Example     Particle Plume Dispersion     Earth Strain Imagery     Seismic Ray Paths     GSRM Tectonic Plate Motion Vector Grids     Earth Strain Axes Download & Run the GEON IDV How to Use the GEON IDV: Basics     More Tips "True 3D" with the GEON IDV Data Online: The GEON Portal, and the UNAVCO Catalog GEON IDV Data Formats and Access Methods NetCDF Data for the GEON IDV UNAVCO's ASCII to NetCDF Data Converters

Data shown in this web page is from Allan K. McNamara & Shijie Zhong, "Thermochemical structures beneath Africa and the Pacific Ocean," Nature 437, October 20 2005, 1136-1139.

Earth Geodynamic Mantle Models in 3D

You can use the GEON IDV to display and investigate data of earth interior structure. Any 3D lat-lon-depth grid of scalar values can be displayed, such as seismic velocity, temperature, or chemical species fraction. You can display vectors, and UNAVCO plans to add a symbol for anisotropy soon. The example here is mantle temperature.

The GEON IDV shows global or local 3d gridded data with vertical and horizontal cross-sections, at any depth or position, contoured or colored by value, or as isosurfaces (3D surfaces of a data value), and with vertical profiles, single point value probes, and others. You can overlay other geophysical, GIS, and map data. Displays choices include maps views and a rotatable 3D globe, and may include time animation The IDV has full interactive controls in 3D including vertical scale, zoom, pan, and rotation, and tools to change color tables for data display, map projections and background maps.

Global Mantle Temperature Data on the UNAVCO GEON Server Catalog

Get sample temperature data from a model of mantle temperatue from the UNAVCO GEON Catalog at http://geon.unavco.org/unavco/catalog.xml. In the IDV use menu choice Data -> New Data Source -> From a Catalog; then, in the window that appears, after Catalogs enter "http://geon.unavco.org/unavco/catalog.xml" Open the mantle data category by clicking on the blue circle by "Mantle Temperature 3D Model," then click the data set you want, such as geomodel/MantleTemperature.nc." and click on Add Source. The IDV connects to the catalog. The source is listed in the IDV's Field Selector window, Data Sources panel.

Make a Plan View (horizontal cross section) Display

In the IDV, in the Data Selector window, in the Fields panel you should see "var." This name comes from the NetCDF data file itself; the IDV does not "know" anything about types of data.

Choose menu choice Projection -> Set Projection with new data. In the Displays panel click on "Color image" under "Plan Views." Click on Create Display. In the display control window labeled "Color Shaded Plan View" that pops up, set the Levels to a value near about 2311.0. A horizontal cross section of colored data values is shown. Use the IDV controls to rotate pan and zoom. A display similar to the picture shown below is made.

You can also make contours, and grid points colored by value. Data probes can sample exact data values at any point in the 3d space.

Mantle temperature model, false color plan view at 2311 km depth

Make a Vertical Cross Section Display

Switch off visibility of the plan view by clicking off the check box in the legend for "var - Color Shaded Plan View." In the Fields Selector window, Displays panel, click on the blue button by "Cross Sections," then on "Color-Shaded Vertical Cross Section," then click on Create Display. (This display is not truly shaded; rather it has grid cells colored by value as does the Plan view.) Rotate the display in 3D with button 3 drag and/or arrow keys.

A display similar to the one shown below is made, as is a new window with the cross section alone. Note the display control window pops up, with choices for color table. You can drag the ends of the cross section to any angle across the 3D grid with the three colored boxes on the line on top of the main display.

Oblique 3D view from southwest of Vertical Cross Section of mantle temperature model
(bottom edge at 2900 km)

Make an Isosurface Display

Switch off visibility of the plan view by clicking off the check box in the legend for "var - Color Shaded Cross Section." In the Displays panel click on the blue button by "3D Surface," then on "Isosurface." Click on Create Display.

A display similar to that shown below is made. The image is an isosurface, the 3D surface where is found (or interpolated) a single identical data value. An isosurface is the 3D equivalent of a contour line in a 2D plot. The isosurface is colored by value (one color for each temperature surface) and shaded to enhance the 3D appearence.

Note the display control window pops up, with choices for color table, and a slider bar named "Isosurface Value" to select the value of the isosurface.

Isosurface of mantle temperature, 52% of core-mantle boundary temperature.
Oblique 3D view of mantle temperature isosurface, from SSW, showing Mid-Atlantic rise feature and others.

Use an IDV Bundle File

An IDV Bundle File is a configuration file in XML that saves all information about a particular data connection and displays. You can easily share bundle files with others via email or online. Try loading the bundle file http://geon.unavco.org/unavco/XIDV/mantle_temperature_3d_global_52.xidv which recreates the display shown above. Cut and paste that URL into the "Data -> New Data Source -> From a Web Server" menu choice window to recreate a display You do not need to connect to data or set up the display; the IDV does it all for you automatically. (This is a big data file and complex display; do not expect instant results.)

Make a Data File

The IDV uses IDV NetCDF format data files. You can make NetCDF files directly as described on that page. If you need a sample cdl file to guide you making your own 3D gridded data files in NetDCF format files, refer to this text CDL file demoTomography.cdl.

You can convert ASCII data files for grids (lat-lon-depth-parameter) to NetCDF. See ASCII converters and UNAVCO GIAG format.