Data Constellation Maps

How to:

Reference:

When analysis of information with a geographical or spatial component is required, a data constellation can also be presented as a map by associating the nodes on the constellation with map images, and geo-code data, such as countries, cities, and zip codes with latitude and longitude coordinates. Data constellation maps are helpful when you need to distinguish regional variations in specific attributes or determine links between specific locations. As with standard data constellations, the height, shape, size, and color of nodes and links on a constellation map can be manipulated to represent other data relationships or characteristics.

The following image shows an example of a data constellation map.

Data Constellation Map

WebFOCUS Visual Discovery includes complete maps of the world, as well as the United States, Canada, and Mexico, with geo-code data for countries, over 400 worldwide cities, and U.S. zip codes. You can find the maps supplied with Visual Discovery in the visdis directory installed with Developer Studio. For example, on Windows, the default directory is \ibi\DevStudio81\ibi_html\visdis\Maps.

Custom maps, such as floor plans and other spatial images, can also be supported by using bitmap images as a base with associated geo-code data. You can also:

The data constellation component supports image maps and vector maps. A vector map is created from a table of data that specifies a series of detailed latitude and longitude coordinates that are used to plot a geographical area. Vector map data can be specified in place of, or in addition to, an image map. One advantage of a vector map is that you can color and extrude the actual map elements. For example, you can color code countries on a world map to reflect population. Maps can also be placed on a sphere to produce a globe.

From the Placement tab, you can overlay an image on the display and position the nodes (bars) according to the x-value and y-value of the map image (for example, longitude and latitude values).

The image you use for the map should be generated by a map program for specific latitude and longitude. The image should be generated with Mercator Projection (most common map programs have this).

What is Mercator Projection? Since the Earth is round and we want to create a flat 2D image, there will be some sort of distortion. Different projections are developed to solve the distortion problem and Mercator is one of them. If a different projection is used, the data points will not be mapped correctly because of the distortion. For example, a city in Florida may appear in the ocean.

The image is defined by: lower left corner Longitude,Latitude and upper-right corner Longitude,Latitude.

For more information, see Data Constellations.


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Procedure: How to Set Up Nodes and Links
  1. Click the Nodes/Links tab in the Visual Discovery Properties dialog box.
  2. In the Nodes field, set:
    • Size to determine the relative size of the node. The size of the node is related to the size of the field value. Select a field from the drop-down list.
    • Style to determine the shape of the node. A small set of node styles is mapped to the values in the selected field in sort order. Shapes are filled circle, filled square, filled pentagon, filled rectangle, framed circle, framed square, framed pentagon, and framed rectangle. Select a field from the drop-down list.
    • Label to specify the text for the node label. For example, if you had a City field, the city name appears when a user hovers over a node.
    • Height to the field you want the nodes to represent. This in effect puts the display in 3D mode, where the nodes appear as 3D bars. The height of the bars will reflect the values in the field.
    • Scale to adjust the relative size of nodes. Move the slider to the right to increase the size or to the left to decrease the size of the nodes.
  3. In the Links field, set:
    • Size to specify the line width. Select a field from the drop-down list.
    • Style to determine the shape of the link. A small set of link styles is mapped to the values in the selected field in sort order. Shapes are filled circle, filled square, filled pentagon, filled rectangle, framed circle, framed square, framed pentagon, and framed rectangle. Select a field from the drop-down list.
    • Label to specify the text that describes the link. Select a field from the drop-down list.
    • Scale to adjust the relative size of links. Move the slider to the right for larger links and to the left for smaller links.
    • Directional to draw links as directed, with arrowheads showing the direction of the link. To use directional links, your data must support to/from links. You can specify these relationships on the Data tab.
  4. Click Apply and then click OK.

    Note:

    • Nodes are the glyphs (3D graphics objects that look like extruded boxes or skyscrapers) that overlay the map image to represent geographical entities, in this case, cities.
    • Links represent a relationship between nodes. In this case, the relationship is a movement of goods between distribution centers.
    • In many cases, a relationship may not exist between nodes that you want to visually represent. In those cases, you still need to provide a table, but simply give it a dummy table that has two fields with values that do not match any of the values in the field selected from the nodes table. Here is a sample table that you can use:
      _dummynode1_        _dummynode2_
      _dummynode1_        _dummynode2_


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Procedure: How to Set the Placement Properties of an Image
  1. Click the Placement tab in the Visual Discovery Properties dialog box.

    Add the map image and the coordinates for longitude and latitude. The image must be in BMP or JPEG (extension .jpg or .jpeg) format. For more information on image requirements, access Visual Discovery online Help and search for the applicable JavaScript API topics.

    In the Position File input area, three distinct parameter strings are required, each separated by a space, as follows,

    longfield,latfield 'imagepath' minmax1~ minmax2

    where:

    longfield,latfield

    Are the actual field names in the data source for the fields that contain the X,Y (longitude and latitude) coordinates for the nodes, respectively. The fields longfield and latfield are case-sensitive.

    'imagepath'

    Is the full path of the map image. Use the Browse button to enter this value.

    minmax1~ minmax2

    Are the minimum X and Y (lower-left corner of the map) and maximum X and Y (upper-right corner of the map) values, separated by a tilde (~) and a space.

  2. Click Browse and navigate to the map file.
  3. Click in the Position File text box and preceding the image path, enter the field names for the X, Y (longitude and latitude) coordinates. Ensure there is a space between Latitude and the path designation. For example:

    Longitude,Latitude 'C:\ibi\apps\session\usMainlandDark.jpg'

  4. In the Position File text box, go to the end of the string. Add the minimum X and Y and maximum X and Y values for the map image. Ensure the values are separated by a tilde (~) and a space. For example:

    Longitude,Latitude 'C:\ibi\apps\session\usMainlandDark.jpg' -125.5,23.5~ -67,50


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Reference: Data Constellations Tab

The following image shows the Data Constellations tab in the Visual Discovery Properties dialog box.

Data Constellations Tab

Mouse
Selects

Uses the mouse to select data.

Labels

Uses the mouse to label nodes and links.

Label

When the mouse is used to label items, fields in the Label section can be used.

Label selected

Labels the selected items.

Clear Labels

Removes all labels.

Node and Link Selection

Enables you to show nodes and links in your graph.

Options available from the drop-down menu are Nodes Only, Links Only, and Nodes and Links. Available options in the linking area are No Linking, Link Both Ways, Nodes -> Links, and Links -> Nodes. For more information, see Nodes/Links Tab.

Link External Selections

Propagates links to other visualization components.

Show Unselected

Shows unselected data in gray. If Show Unselected is not checked, unselected data is omitted from the display.

To add unselected data, either turn on Show Unselected in the Properties dialog box or use the right mouse button menu in the view and choose Select All.

Select a Subgraph
One Step

Increases the selection by including nodes at the other end of the currently selected links. One Step is the same as performing both Step Out and Step In simultaneously.

Step In

Increases the selection by including nodes on incoming links from the currently selected set.

Step Out

Increases the selection by including nodes on outgoing links from the currently selected set.

Component

Increases the selection by including all nodes that are reachable from the current selection (the component).


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Reference: Nodes/Links Tab

The following image shows an example of the Nodes/Links tab in the Visual Discovery Properties dialog box.

Nodes/Links Tab

Nodes

Sets the node Size, Style, Label, Height, and Scale properties for the nodes in your data constellation.

Links

Sets the link Size, Style, Label, Scale, and Directional properties for the links in your data constellation.

For more information, see How to Set Up Nodes and Links.


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Reference: Placement Tab

The following image shows the Placement tab in the Visual Discovery Properties dialog box.

Placement Tab

Position File

The name of a file that contains saved positioning information. If supplied, this file will be read and those positions used for the data visualization nodes. Use Browse to find the placement position file. The complete path to the file can also be typed in the Position File field.

Read

Reads an existing position file.

Write

Writes or saves the positioning of a graph.

Link Weight

Enables you to select a field to weight the link by.

Position

Specifies the position of the nodes. You can position nodes as a hex grid, angular tree, circular shape, top-down tree, map, or globe. If you choose a map, you must specify the longitude and latitude values in the Position File field.

Swap

Improves the placement by exchanging nodes between current positions. When hex grid placement is used, swapping nodes may further improve the placement, based on moving strongly attracted nodes closer together. Strength of attraction is based on the assignment of a numeric field to a link as the link weight.

Because graph improvement can be time-consuming, use the slider to specify a certain length of time, in seconds, for swapping to occur.

Move

Improves the placement by moving nodes that are strongly connected closer together.

When hex grid placement is used, another improvement can be made after swapping, by moving nodes closer together off the initial grid, based on the strength of attraction.

Use the slider to specify the length of time to move, in seconds.

Apart

Readjusts the space between nodes if the Move option places them too close. Use the slider to specify the length of time to readjust, in seconds.

Stop Placement

Stops the placement process, keeping the last positioning.


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Reference: Data Constellation and Data Constellation Map Pop-up Menu

The pop-up menu appears when you right-click a Visual Discovery control in the analytical dashboard. These options do not appear when you are developing a component in HTML Composer.

Show Unselected

Shows unselected data in gray. If Show Unselected is not checked, unselected data is omitted from the display.

To add unselected data, either turn on Show Unselected in the Properties dialog box, or use the right mouse button menu in the view and click Select All.

Selection Type

Enables you to select nodes and/or links that appear in your graph.

Options available from the pull-down menu are Nothing, Nodes, Links, or Nodes and Links.

Selection Linking

Determines how selection is propagated between nodes and links.

Options available from the pull-down menu are No Linking, Nodes to Links, Links to Nodes, Both Ways. Finer characteristics of nodes and links are defined in the Nodes and Links tab.

Label Selected

Displays labels for the selected data.

Directional

Adds or removes arrowheads showing the direction of the link.

Label Node/Link 'name' (Data Constellations only)

Adds or removes the label for the selected node or link.

SHIFT+CTRL+RMB (Data Constellation Maps only)

Changes the action that occurs when you press the Shift + Ctrl + RMB (right mouse button) keys.

Glyph (Data Constellation Maps only)

Changes the shape of the glyphs.

Undo

Reverses the previous action. You may repeatedly undo actions retained in the history file for your current session by selecting Undo over and over again. A description of the previous action appears on the pop-up menu. If you have performed no action, Undo is not available for selection and no action appears to the right of the word Undo.

Redo

Restores the previous undo action. If you have performed no action, Redo is not available for selection and no action appears to the right of the word Redo.

Select All

Selects all of the items in the graph. When you choose Select All, any previous selections are ignored. Selection state returns to the original setting.

Unselect All

When selected, all of the items become unselected. All items appear in the unselected color (gray, by default) or are hidden in the graph (if hide unselected is active).

Toggle All

Reverses the selection state of items. Selected items become unselected and unselected items become selected.

Exclude Unselected

Excludes (temporarily removes) items from the graph.

Restore Excluded

Restores the items you excluded. If you accidentally excluded the unselected, this menu option restores those excluded items.

Save Image

Enables you to save the graph to a GIF or JPEG file.

Copy Image

Enables you to copy the selected component and paste it to another file.

Extruded (Data Constellation Maps only)

In 3D mode in run time, glyphs are drawn from the height to the floor, allowing nodes to be treated like a bar chart on a plane.

Label Item (Data Constellation Maps only)

Enables you to display or suppress the label text. When you right-click a glyph (node or link), this option changes from Label Item, to the text that identifies the selected node or link. For example, if you right-click a node that represents data for Dallas, this option appears as Label Node “Dallas.”

Properties

Takes you to the collection of tabs available for the respective visualization component. Common tabs include Data, Selecting, and Colors.


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