Region Overview:
The Region tab is used to specify the 3D extents of a subvolume of the full VDC domain. This subvolume is intended to be regarded as the "region of interest" of the visualization.
The Region has the following uses:
- It specifies the volume of data that is used for volume visualization and isosurface rendering.
- It specifies the limiting extents where flow integration is performed; i.e. flow lines are terminated when they reach the edge of the Region.
- The "View Region" button at the top of the VAPOR GUI window (described with the View) modifies the viewpoint so as to center on the current region.
- The Flow, Probe, 2D, and Barbs tabs have the capability of using the Region extents to limit or otherwise modify their own extents.
- When using IDL to analyze data, you can click the entry in the Data menu, "Export to IDL", to specify the region extents, which will enable the IDL script to perform operations on just the data in the current region.
The settings in the Region tab can apply in just one visualizer, or can be simultaneously applied in multiple visualizers, by use of the local/global scope selector. This is explained under "Global Tabs in VAPOR GUI"
Control of region extents:
The extents of the current region can be modified in several ways:
- In Region mode, the region be manually manipulated to any axis-aligned box inside the data volume.
- The Region panel has sliders and text boxes to set the center and size of the current Region.
- The region can be reset to the full domain by clicking the button labeled "Maximize Region in Full Domain".
- The extents of a region, or the extents of any other box (Barb rake, flow rake, probe, 2D data, image, contours) can be copied to another box using the "Copy Box Extents" button, after selecting the "From:" and "To:" box extents. This copying applies to the extents in the current selected instance of the renderers specified in the "From" and "To" selectors.
Time-varying region extents: VAPOR GUI allows the Region extents to vary over time. The extents can be specified manually at each time step, or the region extents can be specified in a "Region List" file containing a list of Region extents.
- By default, the Region is equal to the full domain extents at all time steps. By default, when you change the region extents, those changes will apply at all time steps.
- To change the extents at a specific time step, click the button "Adjust Extents" and then change the extents of the region. Henceforth the region extents at that time step will be independent of other time steps and will use the extents you have set.
- To save the current region extents to a file, click "Save Region List". This will result in a file having one line for each time step for which the region are not the default extents. Each line contains 7 values, a time step followed by 3 values indicating the region minima at that time step, and 3 values indicating the region maxima.
- Likewise, a file with 7 values per line is read by pressing "Load Region List", and will result in time varying extents for the time steps specified in the file.
Region Information about Loaded Data: At the bottom of the Region panel is a table of values that can be used to find the dimensions, user coordinates and other attributes of the variables in the current data. The values in this table are not affected by the current visualization. To find out about a variable, specify its name, refinement level, and the time step of interest. The table values indicate the extents of the VDC in user and grid (voxel) coordinates, plus the extents of data available for the specified variable, and the extents of the current region. If the variable is not present in the VDC at the specified timestep and refinement, the grid extents will be shown as blanks.
