Weather and Climate Toolkit Advanced Tutorial

The View Properties window allows you to adjust three viewing options: Display, Legend, and Cache. To open the View Properties window, click View in the viewer menu bar then click View Properties, CTRL-V also opens the window.

Display

The Display tab provides an option to control the automatic addition of the NOAA logo to all saved images, animations and screen captures. There is also a quick reference on how to change the units displayed in the Status bar.

Legend

The Legend tab provides options for changing the: Font, Text Color, and Background Color of the NEXRAD legend. Clicking on the three buttons will pop up a window to change the clicked option.

Cache

The Cache tab controls the internal Cache file. Checking or unchecking the 'Use Data File Cache?' will turn on or off the use of an internal Cache file (On by default). The cache location and size may be edited. The cache is scoured and cleaned upon each startup of the Toolkit.

When gridded data is loaded in the Toolkit, the Grid Properties window should automatically open. If this does not occur, you can open grid properties window manually by clicking View in the viewer menu then 'Grid Prop.'

The Grid Properties dialog allows the selection of the grid variable, time (if present), model run time (if present) and height (if present). The filter allows simple text match filtering of variables or times. Multiple selections may be made by using the 'Shift' or 'Control' buttons. Animations may be created using when multiple times, run times or heights are selected.

When radial data is loaded into the Toolkit, the Radial Properties window should automatically open. If this does not occur, you can open the radial properties window manually by clicking View in the viewer menu then Radial Prop. (CTRL-P also works).

Once the Radial Properties window has been opened there are four properties that can be adjusted: Moment, Cut (Elev. Angle), Show RF Values, and Classify Data.

Moment corresponds to the three different products the Doppler Radar actually senses (in contrast Level-III are derived products from Level-II).
The three moments are:

• Reflectivity: A display of echo intensity measured in dBZ. This product is used to detect precipitation, evaluate storm structure, locate boundaries and determine hail potential.
• Radial Velocity: A measure of the radial component of the wind, either toward the radar (negative values) or away from the radar (positive values). Negative values are represented by cool colors (green), while positive values are represented by warm colors (red). This product is used to estimate wind speed and direction, locate boundaries, locate severe weather signatures, and identify suspected areas of turbulence.
• Spectrum Width: A measure of velocity dispersion within the radar sample volume. The primary use of this product is to estimate turbulence associated with mesocyclones and boundaries.

The Cut (Elevation Angle) is the tilt angle the Doppler Radar is measuring relative to the horizon. Note: these angles change due to the radar's location and its current Volume Coverage Pattern (VCP).

Useful Radar Information Links

• National Weather Service JetStream Doppler Radar Page
• University of Illinois WW2010 Radar Meteorology Page
• The Weather Prediction Radar Education Page
• Wikipedia Weather Radar Page 

Most data sets viewed in the toolkit can be animated (as long as there is more than one file for a time series). Data Services can also be animated but the process is different that what will be covered in this tutorial and you should consult the individual data service tutorial for how animations are controlled.

This tutorial covers animating radar and satellite data also covered are some of the tools used by Data Services. There are two methods of animating in the toolkit: Animation Generator and Screen Capture ("stop animation").

Animation Generator

Creating an animation using the Animation Generator is done by selecting multiple files in the Data Selector (review the tutorial about the Data Selector) To select multiple files in the Data Selector, hold the control or shift keys and click the individual or range of files.
Once this has been done click Animate and the Animation Window will pop up.

The Animation Wizard has four options:

• Load: Loads the selected files into the Animation Window. This feature is explained later in this tutorial.
• Export Frames: Saves each individual image that was selected as one of the following file types: JPEG, GIF, PICT, TIFF, BMP, TARGA, and PNG.
• Export Movie: Saves the selected range of data files as either an AVI Movie or an Animated GIF. Using this feature will give you the option of setting the frame rate using a numerical value.
• Export KMZ: Export the selected data files as a KMZ file (Keyhole Markup language - Zipped) to be used in programs like Google Earth. Review the Google Earth Tutorial to learn about working with exported files in Google Earth.

This animated GIF file was created using the Export Movie feature.

When you select the Load button in the Animation Generator, the selected files are loaded into the Animation Window.

The Animation Window has seven sets of controls. Each controls the following:

• Save All: Saves each individual image that was selected as one of the following file types: JPEG, GIF, PICT, TIFF, BMP, TARGA, and PNG.
• Save Image/Export Movie (Depends on Stop/Play respectively): Whenever an image is stopped in the animation window this button gives you the option to save the currently viewed image. Same file types as Save All apply. / Exports the current animation as either an AVI Movie or Animated GIF (frame rate for both is based on the frame rate slider).
• Previous: Moves a stopped animation back by one frame.
• Play/Stop: Plays or stops the current animation.
• Next: Moves a stopped animation forward by one frame.
• Frame Rate Slider: The slider between the Next button and Rock checkbox that controls the speed of the animation.
• Rock: When checked, an animation runs through each frame normally then runs each frame in reverse in a continuing motion.

The second way to create an animation is by animating multiple Screen Captures also known as stop animation.

To take a screen capture, click Capture in the Right Side Bar or click Tools then click Screen Capture (CTRL-Z also works). Once you have taken several screen captures and would like to create an animation, click Tools then click Capture Animation. The Capture Animation window will then pop up.
Once this window comes up a list of the screen captures you have taken will appear. Select multiple files to animate by holding the control or shift keys and left clicking to select individual or a range of files respectively.

When you have the captures you want to animate selected, click Load. This will load all the images into the Animation Window. Scroll back up the page to review how to use the Animation Window.
Below is a screen capture animation created by taking all the Level-III reflectivity screen captures every hour for 12 hours.

(Image)

Range Rings can be added to the currently viewed radar site to give a visual representation of distance. In order to add range rings you must be looking at NEXRAD imagery.

To add Range Rings to the viewer click View in the viewer menu bar, then click Range Rings. Once this has been done a Range Rings window will open like the one below.

The Range Rings window has two tabs: rings and spokes. The style section below the tabs is inherent to both rings and spokes (more information about styling rings and spokes below).

The Rings tab has 4 customizable options:

• Minimum Range: Defines how far out the range rings will begin relative to the radar site. The default setting is 10.0 but you can type in your own distance or select predetermined ones from the drop down list.
• Maximum Range: Defines how far away the longest ring of the range rings will be relative to the radar site. The default setting is 230.0 but you can type in your own distance or select predetermined ones from the drop down list.
• Ring Increment: Defines the increment distance of the rings relative to each other. The default setting is 25.0 but you can type in your own distance or select predetermined ones from the drop down list.
• Units: Provides a drop down list of units for the three options listed above. Kilometers, Miles, and Nautical Miles are available.

The Spokes which intersect the range rings at a given degree increment can be controlled by the spokes tab.

The Spokes tab has 4 customizable options:

• Start Azimuth: The degree bearing for the starting spoke. The default is 0.0 but you can type in your own degree or select predetermined ones from the drop down list.
• End Azimuth: The degree bearing for the ending spoke. The default is 360.0 but you can type in your own degree or select predetermined ones from the drop down list.
• Spoke Increment: The increment of degrees between spokes. The default is 30.0 but you can type in your own degree increment or select predetermined ones from the drop down list.

The style of both rings and spokes can be changed under the rings and spokes tabs. Clicking on the Color button will bring up a color chooser window. Clicking the drop down menu next to Size will allow you to change the size of the rings and spokes being displayed. Checking or un-checking the Label box will turn on or off the labels of the rings and spokes. Note changing the styles with change both the rings and spokes.

Below is an example of Range Rings and Spokes using the default increments, colored red, size 1, and labeled. The radar being displayed is Level-II imagery from KLIX in New Orleans, LA during Hurricane Katrina.

• Start Azimuth: The degree bearing for the starting spoke. The default is 0.0 but you can
  type in your own degree or select predetermined ones from the drop down list.
• End Azimuth: The degree bearing for the ending spoke. The default is 360.0 but you
  can type in your own degree or select predetermined ones from the drop down list.
• Spoke Increment: The increment of degrees between spokes. The default is 30.0 but
  you can type in your own degree increment or select predetermined ones from the drop
  down list.

The style of both rings and spokes can be changed under the rings and spokes tabs. Clicking on the Color button will bring up a color chooser window. Clicking the drop down menu next to Size will allow you to change the size of the rings and spokes being displayed. Checking or un-checking the Label box will turn on or off the labels of the rings and spokes. Note changing the styles with change both the rings and spokes.

Below is an example of Range Rings and Spokes using the default increments, colored red, size 1, and labeled. The radar being displayed is Level-II imagery from KLIX in New Orleans, LA during Hurricane Katrina.

(Image)

Alphanumeric/Supplemental Data is unique to Level-III radar data that provides detailed information on specific parameters for an identified storm cell.

Data types that show Alphanumeric/Supplemental Data:

Storm Structure (NSS)

• Viewer: Displayed is the radar indicated storm center as a circle with its cell tracking ID
• Info/Data: A table displaying information on storm attributes which include maximum reflectivity, maximum velocity at lowest elevation angle, storm overhang, mass weighted storm volume, storm area base and top, storm position and storm tilt.

Hail Index (NHI)

• Viewer: Hail potential is labeled as either probable (hollow triangle) or positive (filled triangle).
• Info/Data: A product designed to locate storms which have the potential to produce hail. Probable means the storm is probably producing hail and positive means the storm is producing hail.

Mesocyclone (NME)

• Viewer: Displayed is the radar indicated mesocyclone center as a circle with its cell tracking ID
• Info/Data: This product is designed to display information regarding the existence and nature of rotations associated with thunderstorms. Numerical output includes azimuth, range, and height of the mesocyclone.

Tornado Vortex Signature (NTV)

• Viewer: Displayed is the radar indicated Tornado Vortex Signature point as a circle with its cell tracking ID
• Info/Data: A product which shows an intense gate to gate azimuthal shear associated with tornadic-scale rotation.

Storm Tracking Information (NST)

• Viewer: Displayed is the current storm location (bright color) the forecasted movement (darker shades) in 15 minute increments
• Info/Data: A product which shows the storm cell's current location and forecasted movement for each identified thunderstorm cell. This product is used to determine storm movement.

The Alphanumeric Properties window enables you to view the information (alphanumeric and supplemental) for the previously listed data types. To open the window, click View in the viewer menu, then click Alphanumeric Prop. (CTRL-A also works).

Editable options in the Alphanumeric Properties window:

• Show Strom ID: Turns on or off the storm cell tracking identification tag.
• Halo: Turns on or off the dark "halo" around the cell tracking ID text.
• Color: Displays a color chooser window to customize the color of the displayed variable (Changing the color will affect both the point and the cell ID).
• Size: Adjust the size of the point and cell ID on a scale from 1 to 5.
• Show Attribute Table: Brings up a window displaying the Alphanumeric Attribute Table (more information below).
• Show Supplemental Data 1 and 2: Given the data type your are viewing, each button brings up a window with additional data specific to the alphanumeric data property being viewed. Another way to bring up the Supplemental Data 1 window is to click View from the viewer menu, then click Supplemental Data.
• Export Attribute Table: Brings up a save option window to export the Alphanumeric Attribute Table as either a CSV (Comma Delimited), WKT (Well Known Text), or SHP (ESRI Shapefile).

You also have the option to draw several different radar backgrounds that correspond with the time of day of the dataset you are viewing. To do this, simply click on a radar image in the Draw Radar Background list then click Load.

Below is an example of the Storm Structure alphanumeric data being displayed with the Base Reflectivity. (Image)

The toolkit has the ability to export data into the following formats: Native Format (copy), NetCDF, Gridded CF-NetCDF, Shapefile, Well-Known Text, GeoTIFF, ESRI ASCII Grid and ESRI Binary Grid.

Exporting the data is done by using the Data Export Wizard. To access the Data Export Wizard, click on the Export button in the Data Selector after selecting single or multiple files. For more information on the Data Selector, please refer to the Loading Data Tutorial.

Export Steps

There are eight possible steps to the Export Wizard. Some steps are only applicable for certain data types or export formats.

1. Select the export format from the Software Tab and output directory.
2. Select the variable and time, runtime, height (for gridded data) or sweep (for radial data).
3. Select the spatial extent. By default, the current view extent will be selected. The North and South boxes correspond to the Latitude that bounds the top and bottom of the spatial extent. The East and West boxes correspond to the Longitude that bounds the right and left of the spatial extent.
4. Set the value filter, if desired.
5. Set any options specific to the export format. For raster/grid export formats, this includes the cell size, grid dimensions and no data value. Setting the grid dimension size will cause the cell size to be automatically determined, preserving the aspect ratio of the grid (cells are square). Setting the cell size will cause the grid dimension size to be automatically calculated.
6. A summary of the options selected prior to processing.
7. The progress monitoring step.
8. A summary of the data export process.

When using the Data Export Wizard, there are several export formats available: Native Format (copy), Raw NetCDF, Shapefile, Well-Known Text, GeoTIFF, ESRI ASCII Grid, ESRI Binary Grid, and Gridded NetCDF.

Vector (Polygon/Point)

Vector (Polygon/Point) formats (Shapefile, and Well-Known Text) preserve the native structure of the data by encoding the data as polygons (radar only), or points. The polygons represent the exact range bin with vertices in latitude/longitude NAD83 coordinates while the points represent the centroid of the grid cell in latitude/longitude NAD83 coordinates.

Point Export

The cell centroid export allows the greatest flexibility for post-processing. GIS applications can interpolate the point locations into custom grids using a variety of interpolation techniques, projections and resolutions. Some visualization programs can create 3D interpolations and visualizations using the height fields. The fields/attributes for point exports are defined below:

'Radial' (Radar) Data Types:

• 'time' = UTC/GMT time for data
• 'value' = the data value of the selected moment/variable, in the same units used in the map viewer and displayed in the legend
• 'radialAng' = azimuth angle in the radar's polar coordinate system, where 0 is north
• 'surfaceRan' = range from radar site in meters
• 'heightRel' = height relative to radar in meters
• 'heightASL' = altitude above sea level

'Grid' Data Types

• 'value' = the data value of the selected moment/variable, in the same units used in the map viewer and displayed in the legend
• 'time' = UTC/GMT time for data, if available

'Satellite' Data Types

• 'value' = the data value of the selected moment/variable, in the same units used in the map viewer and displayed in the legend

Raster (Gridded) 

Raster (Gridded)formats (GeoTIFF, ESRI ASCII Grid, ESRI Binary Grid, and Gridded NetCDF) are gridded representations of the data in the latitude/longitude NAD83 coordinate system. A simple nearest-neighbor resampling technique is used to populate the output grid when the input data are not on a NAD83 latitude/longitude grid. This includes input data in projections (such as Albers, Lambert or Polar Stereographic), irregularly spaced grids (curvilinear grids) and all 'Radial' (weather radar) data.

GeoTIFF '8 bit' vs. GeoTIFF '32 bit'

The GeoTIFF '8 bit' format are scaled data values between 0 and 255 and do not contain the actual data values. The data are scaled by the min and max values in each file. These files can be useful when a simple grayscale image is desired, however, due to the scale factor changing with each file, animations or any multiple file analysis is impossible.

The GeoTIFF '32 bit' contain the actual data values, stored as 4 byte decimal floating point values.

The 'Native NetCDF' format does not resample the data to the lat/lon coordinate system. The data is represented in the NetCDF format and should exactly match the input data projection, structure and values.

The 'Native Format' format will do a simple copy of the data to the output directory selected. This option can be used to easily download remote data to local disk.

Data Filtering allows you to exclude various ranges of data. Some examples of filter options are: min and max value, min and max distance from radar site, min and max azimuth and min and max height.
Filtering data configured with the Data Filter. To bring up the filter click Tools in the menu bar of the viewer, then Data Filter.

In the example image above, the Radial filter is used for NEXRAD Level-II data. All filters can either be selected from the drop down list or typed in with the exception of Units which must be selected from the drop down list.

Once you have made changes to the filter settings you must Reload the data from the Reload button or the Data Selector. For a refresher on using the Data Selector go to the Loading Data Tutorial.
Below is an example of filtering Level-II reflectivity data from Hurricane Katrina to show only dBZ values of 30 and above. (Image)

Summary

The Point Subset Tool enables an extraction of a time series of data for a single location. The Tool will use predefined Marker Features for the location data. For each selected time or file, the corresponding pixel (Satellite Data), grid cell (Generic Gridded Data), or range bin (Radar data) will be extracted.

Directions

1. Select one or multiple files in the Data Selector, or time steps in the Grid Properties window. Open the Point Subset Tool, either from the 'Tools' menu on the main viewer window, or from the 'More...' link on the Data Selector (for multiple files) or Grid Properties (for multiple time steps).
2. Select one or multiple markers. Please refer to the Marker Features Tutorial for more information on creating and managing markers.
3. Press 'Start' to begin processing. The processing may take some time, particularly if remote files are used and need to be transferred to local cache prior to sub-setting.
4. The results are displayed as comma-separated text, which can be saved to a CSV file or copy/pasted into a spreadsheet program or application for more information on creating and managing markers.

Users may customize the legends of gridded or satellite data. From the Map Layer Selector window and Data Layers tab, select the 'Edit' option link.

The Legend Editor allows the adjustment of the title and dates. The color table is configurable in the Color Table Editor. When editing the title, special variables allow the automatic substitution of information from the currently loaded dataset. The format of the date/time can be adjusted. This is useful when working with yearly or monthly data, when the full date and time is not applicable.

The 'Continued Legend Override' option will apply the customizations to all loaded data. Otherwise the legend will reset to the default with each new file loaded.

The 'Show Transparency in Color Ramp' option will draw a checkered pattern in the color ramp showing the amount of transparency visible for each color range.

Users may customize the color tables of radial, gridded or satellite data. From the Map Layer Selector window and Data Layers tab, select the 'Edit' option links next to the color table selection.
The Color Table Editor allows customization of the colors used to visualize the data layers. The 'Editor' tab allows easier selection of colors and additions or deletions of breakpoints and colors. The color hex and RGBA values are selectable for easy copy and paste using the Control (or Command) + 'C' keyboard commands. Edits in the 'Editor' tab are saved to the 'Text' tab automatically, where the palette format of the color table is available for editing. New color tables may be saved in the internal WCT cache area, using the 'Save' button. The 'Save As' button allows users to save to a custom file location. The 'Load' button allows users to load a text color palette file from a custom file location. New custom color tables are made available in the primary color table selector in the 'Map Layer Selector'.

Example color table text format:

# WCT Color Palette generated from editor 
# 
Units: mm

Color:    150  255  0    0    255
Color:    125  255  200  0    255
Color:    100  255  255  0    255
Color:     75  0    255  0    255
Color:     50  0    0    255  255
Color:     25  0    0    255  255
Color:      0  0    0    124  255

Each line is a value and color breakpoint. The first column of 'Color:' indicates a color/value breakpoint. The second column is the value. The next three columns are the 0-255 Red, Green, Blue (RGB) values. The final column is the 0-255 alpha (transparency) value, where 255 is fully opaque and 0 is fully transparent.

Google Earth I

This tutorial explains how to quickly export the current view into Google Earth. Before proceeding, please review the following tutorials and prerequisites:

• Completion of the Introductory Tutorials and general comfort using the Viewer.
• The Loading Data Tutorial.
• Google Earth installed on your computer. Google Earth Home Page.
  Have a basic understanding of how to use Google Earth. Visit the Google Earth Help Page.
  After loading a data file into the Toolkit, press the 'Launch KMZ' button on the right side of the main viewer window. The 'Save KMZ' button provides the same functionality, but allows the user to choose the location of the saved KMZ file. Once you have clicked 'Launch KMZ' or 'Save KMZ' button, the KMZ Export Options window will appear.
   

The KMZ Export Options window is where you can adjust visual and save options for the KMZ file. The options are explained below. Note that this example is for NEXRAD data (Radial data structure) and these options are slightly different for Gridded Data.

• Altitude(m): Controls which view type will be used in the export: 2D (Drape over surface) or 3D (Drape over sweep model - real height).
• Elevation Exaggeration: Scale factor used to apply exaggeration to the vertical values. Only applicable for the 3D (Drape over sweep model) export view type. Note: In the standalone Google Earth application, the elevation exaggeration (found in the Options dialog) only applies to the terrain, not 3-D data draped on models. When exporting a KMZ file, the elevation exaggeration is provided as an value the user can adjust. The user must adjust Google Earth's elevation exaggeration to match, if desired.
• Create Shadow? When checked will draw a "shadow" of the currently viewed radar image draped over the ground. Only applicable for the 3D (Drape over sweep model) export view type.
• Output File: Displays the output file full path. Click Browse to bring up the Choose Output File window. Note that the 'Launch KMZ' option will not include the 'Output File' section and all files will be automatically written to the WCT cache, which defaults to the User's home directory ( {user.home}/.wct-cache ).

Google Earth II

This tutorial explains how to export a series of radar data files (other formats will follow the same procedures) from the Toolkit and load into Google Earth for viewing as a 'Time Animation'.

Before proceeding, please review the introductory tutorial and be familiar with:

• Completion of the Basic Tutorials and general comfort using the Viewer.
• The Loading Data Tutorial.
• The Animations Tutorial.
• Google Earth is installed on your computer. Google Earth Home Page.
• Have a basic understanding of how to use Google Earth. Visit the Google Earth Help Page.
   

This tutorial will start with the Animation Generator.

From the Animation Generator, click Export KMZ to begin the export process. Once you have clicked "Save KMZ" a KMZ Export Options window will appear.

The KMZ Export Options window is where you can adjust visual and save options for the KMZ file. The options are explained below. Note that this example is for NEXRAD data (Radial data structure) and these options are slightly different for Gridded Data.

• Altitude(m): Controls which view type will be used in the export: 2D (Drape over surface) or 3D (Drape over sweep model - real height).
• Elevation Exaggeration: Scale factor used to apply exaggeration to the vertical values. Only applicable for the 3D (Drape over sweep model) export view type.
• Create Shadow? When checked will draw a "shadow" of the currently viewed radar image draped over the ground. Only applicable for the 3D (Drape over sweep model) export view type.
• Output File: Displays the output file full path. Click Browse to bring up the Choose Output File window.
  Export Frames Progress Window

There are three progress bars in the "Export Animation Progress" window. There is also a Cancel Animation button if you need to stop the processing.

• The first bar (from the top) shows the processing progress on the current individual data file.
• The middle bar shows the processing progress for the entire animation being generated.
• The bottom bar displays how much memory is currently being used by the animation process.

Once the animation processing is complete a window will pop up alerting you.

To open the exported KMZ file in Google Earth, you may press 'Yes' button when prompted following the completion of the animation. In addition, the KMZ file may be double-clicked, dragged and dropped onto Google Earth or opened via the 'File' menu in Google Earth.

The options that will be unique to viewing the Weather and Climate Toolkit's KMZ output in will occur in the Places tab.

Underneath the NOAA Weather and Climate Toolkit Generated Animation folder there are 3 subfolders: Image Frames, Exported Data Extent, and Overlays.

• Image Frames: Are the actual image frames. Their order is controlled by the radar time stamp.
• Exported Data Extent: Are outlines of your view extent when the images were made in the toolkit. There are two available Outline and Background. Outline is a solid white box and Background is a lightly shaded black box.
• Overlays: Contains all the Legends for each image frame as well as the NOAA Logo.
   

Useful Tools:
From the Google Earth User Guide

Transparency Slider

You can adjust the transparency of an overlay from completely transparent to fully opaque whenever it is selected in the viewer. By adjusting the transparency of the overlay image, you can see how the overlay image corresponds to the 3D viewer imagery beneath.
Located underneath the Places tab.

Time Slider
 

1. Click these arrows to move the time range earlier or later.
2. Drag these range markers to the right or left to re-define the time range of data displayed.
3. Click this to play an animation of the sequence. This works best if you move the range markers to define a time range smaller than the whole set.
4. Timeline Options:
   - In the time slider controls area, click the wrench 'Settings' icon
     -- Start and End date/time: Manually set the time extent in the Google Earth display.
     -- Display Time In: Choose the time zone displayed in the time slider.
     -- Animation speed: Use this slider to set the speed of the animation that occurs when you click the play button on the time slider.
   When you are finished, click OK.
5. Drag this to move the time range earlier or later.
    

Navigation Controls