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Unidata IDV Workshop for version 6.2u2 > Accessing and Displaying Data

3.2 Working with Gridded Data
Gridded data can be the output from a numerical model or an objective analysis of observational data. Each gridded data source is comprised of a set of 2- and/or 3-D fields. Each field may have of one or more times associated with it. The IDV supports a variety of ways of visualizing gridded data. In this section we will explore some of these.

3.2.0  Loading Gridded Data
Gridded data can be accessed in the IDV from a remote server or from local files. For the exercises in this section, we will use ETA model output from the COMET Case Study on Bow Echoes (39) from June 29, 1998.
3.2.1  Using the Field Selector
The Field Selector is used to select data sources, parameters, data times, and types of displays to use for creating visualizations.
3.2.2  Using the Display Controls
Each display has a display control associated with it. A Display Control Window is a panel or window with menus, buttons, sliders, and other widgets to control a display. When a display is first created its display control is added to the Dashboard or pops up in a separate window depending on your configuration. The control also has a legend shown in the View Window's legend panel.
3.2.3  Plan Views of Gridded Data

Plan views are horizontal displays of two dimensional data. These data can be true 2D fields (e.g., sea level pressure) or a slice of a 3D dataset at a constant pressure or height (e.g., 500 hPa heights). The IDV can display these plan views as contours, color filled contours, or color shaded displays.

3.2.4  Isosurfaces of Gridded Data
While plan views of 3D fields are useful, the three dimensionality of the atmosphere can be displayed in the IDV using isosurfaces. An isosurface represents a 3-D surface that connects points with the same value. On one side of the surface, values are greater than the surface value; on the other side, values are less than the surface value.
3.2.5  Cross Sections of Gridded Data
Cross sections of data can be useful to show the variation of a field along a transect. In the IDV, a cross section display consists of a selector line and display in the main window, and a 2D display of the cross section in the control window.
3.2.6  Using the Display Legends
3.2.7  Probing Gridded Data

The IDV has a variety of data probes that can be used with gridded data. Probes include value readouts, vertical profiles, model soundings, time/height cross sections and time series displays.

3.2.8  Probing Gridded Data (continued)
3.2.9  Vector Displays

Vector components (e.g. winds, ocean currents, mantle plate velocities) can be displayed in the IDV in a variety of ways.

3.2.10  Grid Trajectory Displays

The IDV can display 2D and 3D grid trajectory data as a derived field based on the horizontal and vertical wind components.

3.2.11  Grid Isentropic Analysis

Isentropic analysis is a common and effective way to diagnose horizontal and vertical motion of the atmosphere, the combination of 3D visualization feature of the IDV and the isentropic analysis helps us better visualize the dynamic and stability of weather phenomenons.

3.2.12  Working with Large Grids

Displaying high resolution grids in the IDV can be memory intensive. If you are reading from a remote server, you also have to deal with the latency of reading the grids across the internet. There are several strategies you can use to reduce the amount of memory used by the IDV.

3.2.13  Hovmöller of Gridded Data

Hovmöller diagrams excel at displaying data as a function of time and location.

3.2.14  Doing More with Grid Displays
Additional exercises you can do with gridded data.
3.2.15  Working with Ensemble Grids

Displaying ensemble grids in the IDV can be memory intensive. If you are reading from a remote server, you also have to deal with the latency of reading the grids across the internet. There are several strategies you can use to reduce the amount of memory used by the IDV.

3.2.16  Cross Boundary Subset of Grid Coverage Data

This section describes how to make plots from the cross boundary subset of a cyclic rectilinear grid data.

3.2.17  Working with NcML

NcML is an XML representation of netCDF metadata, NcML is similar to the netCDF CDL (network Common data form Description Language), except, of course, it uses XML syntax..

 


Previous: Using the Data Source Chooser Next: Loading Gridded Data Table of contents Frames User guide
Unidata IDV Workshop for version 6.2u2 > Accessing and Displaying Data