Section II: 4dwx Overviews and Application Tutorials.
L. JViz (JADE Visualization Tool).
This document provides the forecasters and other users with a high level overview of the 2-D data visualization tool called JViz, a description of its application to range meteorological needs, and a tutorial on its use in daily operations.
1. Overview.
The JViz tool is a configurable application that provides an intuitive user interface for viewing two-dimensional integrated data sets. The tool allows for configurable data layers to be displayed in maps for different times and altitudes, and provides standard map operations such as zooming, panning and querying data sets. For 3D data sets, vertical cross sections can be taken to show slices of data over a flight path. In addition, JViz provides the ability to view virtual and observed soundings in a SkewT plot.
Figure 1 depicts what JViz would typically look like upon startup. The data layers, altitude and time are configurable and hence would affect what actually is displayed in the application.
Figure 1. JViz Startup Window
II-L-1
Figure 2. JViz User Interface
The realestate of the JViz application is divided into functional areas as depicted in Figure 2. The main map for the tool is displayed in the center of the window. As in any application, the menu bar is located at the top of the window, and contains several options that will be covered later in this document. Near the top of the window, and on the left side are two different toolbars that contain shortcuts and tool buttons. The right hand side of the window contains an Altitude Controller that allows the user to look at data at different altitudes. In Figure 2, the "current altitude" is approximately 880 mb. The bottom of the screen contains the Time Controller and a list of the categorized data layers available for display. The Time Controller provides an interface for changing the application's current time, and is currently showing data for 0:00Z. Each layer listed below the Time Controller depicts the available data sets as "dots", lined up vertically to coincide with the Time Controller. Changing the Time Controller's "current time" will affect which data set (or dot) is selected for each layer. In addition, data layers can be turned on/off by clicking on the check box located to the left of each layer.
3. Data Layers and the Time Controller.
JViz is configured with a predetermined set of data layers. The data layers are grouped according to the configuration file (and the specific groups and layers may vary between ranges), and are displayed at the bottom of the main JViz window. Each group is openable/closeable by clicking on it's respective expand/collapse button. In the example below, "Aberdeen RT-FDDA Layers" is a data layer group that contains several data layers, "Temperature", "Dewpoint", etc. Layers can be turned on or off by clicking on their respective checkboxes, and if the layer has an associated color scale, that color scale will appear in the dropdown as shown in Figure 2.
Figure 3. Time Controller and Data Layers with Available Data Sets
Exercise: Turn on/off one or more data layers. Note that the data for that layer now appears in the main map. If a color scale exists for the layers that you have turned on/off, identify them in the color scale dropdown.
The Time Controller appears above the list of data layers. In Figure 3, the Time Controller has a time range window of approximately 4 hours wide, from slightly before 12:00 Z to slightly after 16:00 Z. To the right of each data layer under the "Available Data Sets" column lies a "dot" indicator for each data set available for that layer. These data set dots are lined up vertically with the Time Controller, and appear gray when the data layer is disabled (off) and blue when enabled (on). For each data layer, the currently selected data set appears bigger than the rest, and if the layer is enabled, the selected data set dot will have a black circle around it. If the data layer does not have any available temporal data sets for the Time Controller's time range, then the words "Static Data" will appear to the right of the data layer in lieu of the dots.
4. Time Controller Details.
The Time Controller's "current time" can be changed by sliding it's orange slider bar to a different time. Changing the "current time" will change the current data set for each layer, by selecting the data sets that are on or before the "current time". For example, if one moved the Time Controller's slider to
14:00 Z, the 14:00 Z data set would be selected for the "Temperature" layer, and the approximately 13:52 Z would be selected for the "Infrared Temperature" layer. Changing the Time Controller's current time does not affect layers that have the text "Static Data" in lieu of data set dots.
Exercise: Turn on a layer that has data set dots, such as "Temperature". Drag the Time Controller's current time to a different time, and note the effect it has on the various data layers - each data layer's data will potentially change, as well as that layer's "current" data set dot. Identify the selected data set for various layers.
The initial time range window and current time for the Time Controller is determined by the configuration file. However, the Time Controller has a configuration window that allows the user to
Figure 4. Accessing the Time Controller Configuration Window
change it's time range and other attributes. This configuration window is accessible both from the "Configure -> Time Controller..." and the horizontal toolbar, as shown in Figure 4.
The Time Configuration Window, as shown in Figure 5, allows the user to change the start time and end time for the Time Controller's time range. In doing so, each layer will query it's server for available data sets that fall within that time range. This may include data sets in the past as well as data sets potentially in the future (eg: forecasts), as long as they fall within the new time range. In addition, the user can specify the Time Controller's tick interval and whether or not the Time Controller's current time slider will snap to the tick marks.
Exercise: Open the Time Configuration Window. Change the Start Time to be one hour before the original start time. Change the tick interval to "1 Hour", and turn off "Snap To Tick". Click "Apply" (note that this may take several seconds). Notice that the Time Controller in the main window will now reflect your change, and that the data layers will potentially have additional data set dots available. Move the Time Controller's current time slider. Open the Time Configuration Window again, and turn on "Snap To Tick".
Figure 5. Time Configuration Window
II-L-4
5. Animation.
Figure 6 depicts the various Animation Controller buttons that are visible within the main JViz window, to the left of the Time Controller. Pressing the "Play Backward", "Sweep" or "Play Forward" button will begin the animation sequence for the data layers that are currently enabled. One animation frame is created for each major tick on the Time Controller, and the frequency of ticks can be changed through the Time Configuration Window as shown in Figure 5. Tip: a high frequency of ticks or animation frames runs the risk of running out memory during animation (this bug is on the list of "TODOs").
During the first pass of animation, data is loaded and rendered for all enabled data layers, and is cached for successive iterations thereafter. As a result, the first pass of animation is usually slower than successive passes. When "Stop" is pressed, or when the user does anything (eg: resize) in the user interface, the animation cache is flushed. Animation should normally be stopped when the user wishes to change something in the application, though this is not required.
Figure 6. Animation Controller Buttons
The Animation Controller can also be configured via the Time Configuration Window's "Animation" tab, as shown in Figure 7. Both the minimum "Delay Between Frames" and the "Dwell at the End of the Loop" can be set in the units of milliseconds.
Figure 7. Animation Configuration
Exercise: Open the Time Configuration Window and verify that "Snap to Tick" is on, and that the tick interval is set to 1 hour. Click on the Animation tab, and change the delay to 100 milliseconds and the dwell to 0 milliseconds. Apply the changes. Experiment with stepping
II-L-5
the animation, and playing the animation forward, backward, and in sweep mode.
6. Altitude Controller.
JViz allows the user to change the current altitude of the main map by using the Altitude Controller. The right hand side of Figure 2 depicts the Altitude Controller that has an altitude range of 50
- 1000 mb, and a "current" altitude of approximately 870mb. The actual range and units for the Altitude Controller is determined intiatially by the startup configuration file, and may appear differently in your display as a result. The current altitude can be changed by dragging the orange altitude slider to different altitudes, which will cause 3D data sets to reload accordingly. The units of the Altitude Controller are user configurable, and may be changed through the Altitude Configuration Window, accessible from either the horizontal toolbar or the "Configure->Altitude Controller..." menu item (see Figure 8).
Figure 8. Accessing the Altitude Configuration Window
Exercise: Turn on a "Temperature" layer or equivalent 3D data layer. Slide the Altitude Controller's current altitude to different levels, and note it's affect on the map. Access the Altitude Controller's Configuration Window, and change the altitude units to either Feet, Flight Level, Pressure or Meters. Note the affect on the Altitude Controller in the main JViz window.
7. Different Kinds of Data Layers and Data Layer Configuration
Although the different data layers are defined within the JViz configuration file, there typically will be certain types of data layers. Each data layer type exists as a category or group of data layers. Figure 9 shows a typical JViz configuration with 7 groups of data layers. Each data layer within JViz provides user configuration options which depends on the specific data layer, and the configuration is accessible from the "Configure" menu. Within the "Configure" menu, there exists submenus for each data layer group, and submenutitems for each data layer (see Figure 10). The data layer types and their configuration options are described below.
Figure 9. Data Layer Groups/Categories
(a) RT-FDDA Layers
The "RT-FDDA" group contains data layers that typically have 2D or 3D model data sets, such as Temperature and Dewpoint. When enabled, these data layers will appear as gridded data sets within the main map, and each will have a color scale associated with it that will appear in the color scales dropdown. In addition, these data layers have configuration options as shown in Figure 11. For all RTFDDA layers one has the options to turn on/off the background grid and contours, and can change the layer's transparency. Most RTFDDA layers will also have color scales associated with them, and will allow the user to change the color scale's minimum and maximum, as shown in Figure 12. Tip: This becomes especially useful when the data being displayed has extreme values that fall off of the data layer's color scale.
II-L-7
The "Wind Speed" RTFDDA data layer will typically have additional configuration options to account for wind barbs. Figure 13 shows a sample configuration window for the "Wind Speed" data layer which allows the user to toggle wind barbs on and off, and increase or decrease the wind barb density.
(b) Satellite Grids
The "Satellite Grids" group contains data layers such as "Water Vapor" and "Infrared Temperature". The only configuration option provided for these data layers is transparency. Tip: Transparently comparing the satellite "Water Vapor" to the RTFDDA "Relative Humidity" layer near 400 mb can give a good indication as to how well the model data matches the satellite data.
(c) Surface Observations
The "Surface Observations" group typically contains data layers such as "SAMS", "Mesowest and WMO" and "Lightning". These represent data layers consisting of true observations, and provide the standard transparency configuration option. The "SAMS" and "Mesowest and WMO" data layers provide additional configuration options to toggle on and off the different fields within the observation, such as "Temperature". An example is shown in Figure 14. Note that these layers do not have color scales associated with them, and therefore will have disabled color scale options within the "Color Scale" tab.
In addition, these layers typically provide mouse over information (ie: ToolTips). For
II-L-8 example, if the "SAMS" data layer is enabled and has available data sets, SAMS will appear on the map. If the user "mouses over" the various SAMS in the map, they will see additional summaries of information that pop up on the screen when the mouse is over the observation, and that disappear when the mouse is moved away.
(d) Soundings
The "Soundings" group contains virtual and observed sounding data layers that are described in the Virtual and Observed Soundings section of this document. These layers provide the standard transparency configuration option.
(e) ATEC Range Boundaries
The "ATEC Range Boundaries" group contains one static data layer for each of the ranges, and each simply consists of an overlay of the range's boundaries. These layers provide the standard transparency configuration option.
(f) Overlays
The "Overlays" groups contains preconfigured overlays of static GIS-like data, such as "Topography", "Rivers" and "Highways". Again, each provides the standard transparency configuration. Tip: These are large data sets and may hinder rendering performance if many of these are turned on at once.
The "Lon/Lat Reference" data layer will provide reference lines of constant latitude and longitude within the map. This layer provides additional configuration options to specify the longitude and latitude increments to be used when rendering, as shown in Figure 15.
Exercise: Experiment with the Configuration Options and ToolTips for various data layers.
8. Data Layer Order Manager
JViz allows multiple data layers to be visible at once, effectively layed on top of one another. If multiple data layers are visible, one may wish to move layers up and down, and can do so through the Layer Order Configuration Window. The Layer Order Configuration Window is accessible through both the horizontal toolbar and the "Configure->Layer Order..." memu item, as shown in Figure 16.
The Layer Order Configuration Window depicted in Figure 17, displays the names of all of the data layers within the main JViz map. Greyed out entries represent layers that are disabled/invisible, and black entries represent enabled/visible layers. The top most layers in the map are shown at the top of the layer list, and the bottom most layers in the map are shown at the bottom of the list. By selecting a specific data layer, one can enable or disable the layer, as well as move that layer to the top or bottom, or up and down one layer at a time.
II-L-10
Exercise: Access the Layer Order Configuration Window. Experiment with turning layers on and off, and moving them up and down.
9. Data Layer Status Window
Data layer status can be viewed with the Data Layer Status Window. This window shows data loaded and data validity times, which is especially useful for non-static data layers. The Data Layer Status Window is accessible via the button on the horizontal toolbar, as well as through the "View->Layer Status..." menu item, as shown in Figure 18. Figure 19 depicts a sample Data Layer Status Window, and
II-L-11
10. Lon/Lat Locator (GPS Tool)
The Lon/Lat Locator tool provides the user with longitude and latitude coordinates for the location of the mouse within the main JViz map. To access the Locator Tool, press the "GPS" icon on the horizontal toolbar, as shown in Figure 20. When the tool's window has opened, move the mouse around within the map, and notice that the longitude/latitude location is displayed in the locator tool's window.
Exercise: Access the Data Layer Status Window. Access the Lon/Lat Locator Tool and
identify the lon/lat coordinates of the mouse.
11. Zooming, Recentering and AOIs (Areas of Interest)
JViz provides standard map operations such as zooming within the map, recentering the map and a viewing predefined areas of interest. The zooming and recentering operations are accessible from the vertical toolbar on the left hand side of the map, as shown in Figure 21. Zooming is performed by depressing the Zoom button which remains depressed until a new zoom box is entered into the map, and changes the mouse cursor to a crosshair. To specify a new zoom box, click the the mouse in the map at the upper left of where you wish to zoom, and drag the "rubber-banding" rectangle down to the right until it's in the correct spot. The aspect ratio of the zoom box remains the same as the map, and can be changed by resizing the main window.
JViz performs "smart zooming" and will always attempt to give the user the "best" data possible. When one successively zooms down into the various domains of the ranges, such as zooming from DPG's Domain 1 down into DPG's Domain 3, JViz will return the highest resolution data available for the new zoom area.
The Undo Zoom button reverts back to the last view of the map, and can repeatedly be pressed until the original map view is reached. The Undo Zoom button works for all zoom/pan/AOI operations, and will consistently revert back to the previous map view.
Recentering is performed by depressing the Recenter button from the toolbar, and clicking within the map on the new desired map center. Again, the aspect ratio of the map is retained, and the clicked point will become the center of the new map view.
Areas of Interest (AOIs) are predefined within the JViz configuration file, and can be different for each of the ranges. The AOIs are accessed through the "AOIs" menu, and will cause the map to "snap" to the predefined Area of Interest. Currently, there is a "CONUS" Area of Interest that will revert the map back to the CONUS view.
Exercise: Experiment with zooming and the Undo Zoom button. Experiment with recentering the
map. Move to various Areas of Interest, and occasionally see what effect the Undo Zoom button
has. Experiment with "smart zooming" and identify when it occurs.
12. Vertical Cross Sections
Vertical cross sections can be viewed by specifying a flight path with waypoints within the plan view map. Flight paths are specified by depressing the Vertical Cross Section Button from the toolbar (see Figure 21), and then clicking within the map for each waypoint along the path. Each waypoint along the path initially appears as a number with a white background on the map, and when submitted, the first and last waypoints change to "S" (Start) and "E" (End) respectively. To submit the path and view the cross section, double click on the last waypoint, or right click and select "Submit Cross-Section". To cancel the flight path, right click and select "Cancel Path". Figure 22 shows a sample flight path through the plan view.
The Vertical Cross Sections Window can be viewed by submitting a new flight path, or by clicking on the cross section icon
in the horizontal toolbar. A sample cross section is shown in Figure
23. The waypoints from the flight path appear as vertical lines labelled as in the plan view. The data layers that appear within the cross section window directly correspond to the layers that are turned on within the map view. For example, if Temperature is turned on in the plan view, it will appear in the cross section.Tip: With the exception of Topography, you can only see one layer at a time in the cross section (this bug is on the list of "TODOs"). Only 3D layers will appear in the cross section, meaning that 2D fields such as metars or ground temperature will not.
Figure 22 also shows that there is an Altitude Controller within the Vertical Cross Sections Window. The current altitude of the plan view is represented as a solid black horizontal line through the cross section, and corresponds to the current altitude of the Altitude Controller within the Vertical Cross Sections Window. The plan view's and cross section's Altitude Controllers will always represent the same altitude range, current altitude and altitude units, and changing either will change the other.
User specified flight paths are stored in memory as a "History", as can be seen in Figure 23. This enables the user to switch back and forth between historical flight paths. In addition, JViz is preconfigured with a set of "Classic" flight paths (which can differ across ranges) and can be viewed at any time.
Exercise: Create several cross sections by defining flight paths within the plan view. Turn on and off various layers from the plan view, and note which ones appear in the cross section view. Switch back and forth between the flight paths you just created. Select a "Classic" flight path. Change the
Close the window, and reopen it using the
icon.
13. Virtual and Observed Soundings - SkewT
JViz provides the ability to view SkewT plots for both virtual and observed soundings. Both virtual and observed soundings exist as seperate data layers within the plan view, as shown in Figure 24. These data layers represent the available sounding locations, either virtual or observed, for which actual soundings can be plotted within the SkewT.
The Virtual Soundings data layer contains sounding locations that have previously been specified by the user, and will initially contain zero sounding locations. In order to specify a virtual sounding location, first enable the Virtual Sounding data layer in the plan view. Depress the Virtual Sounding Tool button in the toolbar, and click within the map at the desired sounding location (note that one may have the Lon/Lat Locator window open to help with click accuracy). If the clicked point is at a location that is not covered by the forecast model, a dialog will appear notifying you that the click point is invalid. For valid click points, the SkewT window will then appear as in Figure 25 with a new data layer labelled "Virtual Sounding #", where # designates the first, second, third, etc virtual sounding you may have specified. In addition, the virtual sounding location appears with the same label in the plan view, and is contained within the plan view's Virtual Sounding data layer. Figure 24 shows Virtual Sounding 0, 1 and 2 on the plan view map, and shows the mouse over tooltip that is displayed when the mouse is brought over the Virtual Sounding 0 location.
Exercise: Turn the Virtual Soundings data layer on and off in the plan view. Note it's effect on the Virtual Soundings Tool button in the toolbar. Create a new virtual sounding somewhere in Colorado. Identify the new sounding location in the plan view, and the new sounding data layer in the SkewT.
Observed soundings work in a similar fashion to virtual soundings. The plan view contains the Observed Soundings data layer that contains all of the observed sounding locations. The data set dots for this layer represent times for which observed soundings are available, and the particular set of available soundings will typically be different for different times. Figure 24 shows that there are different sets of observed soundings for 12:00 Z, approximately 12:50 Z, 14:00 Z, etc. To select a specific observed sounding, verify that the Observed Soundings data layer is enabled in the plan view. Depress the Observed Sounding Tool button in the toolbar, and then select one of the available observed sounding locations in the map. As with virtual soundings, the SkewT window will then appear with a new sounding data layer whose name and color matches the name and color of the sounding location in the plan view. For example, Figure 24 shows that the sounding location "KDNR" is blue, and Figure 25 shows a new data layer called "KDNR" whose plot is in blue.
Exercise: Turn the Observed Soundings data layer on and off in the plan view. Note it's effect on
the Observed Soundings Tool button in the toolbar. Create a new observed sounding by selecting
an available sounding location in the plan view. Identify this new sounding location in the plan
view, and the new sounding data layer in the SkewT.
14. The SkewT Window
The SkewT Window is shown in Figure 25, and is accessed by creating new soundings (virtual or observed) or by clicking on the
icon in the plan view's horizontal toolbar. The window looks similar to the main map in that the data layers are categorized and appear at the bottom of the window with their data sets represented as dots lined up with the Time Controller. The SkewT's Time Controller and animation controls are directly tied to those in the main map. Therefore, the SkewT's Time Controller and the main map's Time Controller will always coincide, and changing one will similarly affect the other. The data set dots for each sounding data layer represent available data sets for that layer. For virtual sounding layers, the dots represent times where model data is available and for observed sounding layers, the dots represent the time for which an actual sounding was made at that layer's sounding location. When the Time Controller's current time is changed, each sounding layer will attempt to load a new sounding (at it's specific location) on or before that time.
The rest of the SkewT Window contains the SkewT plots and the wind staves. Data tracings and labelled wind barbs are shown for each enabled sounding data layer. The data plots for each layer consist of both temperature in a solid line style and dewpoint in a dashed line style. Each tracing is color coded to match the color of the sounding data layer's location in the plan view. Mouse over tooltips are provided for each data point in a plot, as can be seen in Figure 25. In addition, each sounding data layer provides transparency configuration in it's respective Configuration Window, acessible through the SkewT window's "Configure" menu.
Two additional data layers exist within the "Overlays" group regardless of the number of sounding data layers. The SkewT Axes data layer contains the "Families of Lines" background which can be toggled on/off and has configuration options to turn on/off each family of lines. The SkewT Legend data layer can be toggled on/off as well, and when on, will display the color legend for each sounding data layer that is enabled. Transparency configuration exists for both the SkewT Axes and the SkewT Legend data layers.
The SkewT Window also provides zooming and unzooming within the main SkewT plot. These buttons are located on the SkewT Window's toolbar, and work in the same manner as the zoom/unzoom buttons on the plan view map.
Exercise: Turn the various sounding data layers on and off. Note the effect on the plots, wind staves and the legend. Identify the temperature and dewpoint tracings. Change the transparency for a sounding data layer. Change the Time Controller's current time and note it's effect on the plot(s). Change the transparency of the SkewT Axes and SkewT Legend. Turn on/off the various families of lines. Zoom and unzoom within the SkewT plot. Identify tooltips for the various plots.
