table_to_scatter_field

Synopsis

maps the data in an array of DBcolumn to a scattered field.

Input Ports

Parameters

Output Ports

Description

Table_to_Scattered_Field maps the data in an array of DBcolumn to a 1D, 2D, or 3D scattered field (an unstructured field that can store scattered data). The data to be mapped is usually query data returned by DBquery or Query.

You typically use scattered fields to represent sparse data, whose columns have many missing values, or nonconnected data, in which there are no internal logical connections between database records. When mapping query data to a scattered field, each record is viewed as a separate point that may have several data values associated with it.

You can visualize scattered field data directly using glyph modules. Alternatively, you can map it to the an unstructured field type using a triangulation process (or, in 3D, a tetrahedration process). After mapping it, you can apply most AVS/Express visualization techniques to the results; for example, isosurface, slice, or surface_plot. This type of visualization is suitable mainly for cluster analysis.

Table_to_Scattered_Field provides a number of parameter values that control various aspects of the mapping.

Axis parameters

You use the X Axis, Y Axis, and Z Axis selection menus to select one, two, or three columns that will serve as the coordinate axes of the resulting scattered field. The number of spatial dimensions in the output field will be one, two, or three, respectively. You use the On toggle associated with each menu to turn the corresponding axis on.

You use the Axis Setup menu to specify a column whose axis parameter you want to set. This parameter value is used when you select the column as a coordinate axis. The Discrete parameter is available. It specifies whether the coordinates along an axis are discrete or continuous.

If you select Discrete, discrete coordinates are used. They are the indices of the rows in a column, rather than the rows' values. Note that every row is assigned its own index value, including duplicate row values. (By comparison, Table_to_Uniform_Field uses only unique values.)

Discrete coordinates are particularly useful with numeric data such as area codes or with string values. For example, if the column contains the string values "John", "Bob", "Bob", "John", "Bill", the coordinates are 0, 1, 1, 0, and 2, where 0 represents "John", 1 represents "Bob", and 2 represents "Bill".

If you deselect Discrete, continuous coordinates are used; that is, each value in the column is treated as a separate coordinate value.

• Continuous coordinates cannot be used with string values.

Data parameters

You use the Field Data selection menu to select the columns that will become data components in the resulting scattered field. You use Data Setup to specify a column whose data parameter you want to set. This parameter value is used when you select the column using Field Data.

The data parameter sphere radius is available. Selecting sphere radius for a particular column puts its data components into a field with a special ID. When visualized, the renderer treats this data as sphere radii.

Input Ports

columns[]

An array of type DBcolumn that contains the query data returned by a SELECT statement. This is the output of a DBquery module or Query macro.

parent

The UI parent, of type UIconnection.

Parameters

X Axis

A menu from which you can choose the name of a column that will serve as the X coordinate axis. The possible values are the names of the columns in the columns[] input por

On

A toggle, located to the right of the X Axis menu, that turns on or off the X coordinate axis. The default is on.

Y Axis

A menu from which you can choose the name of a column that will serve as the Y coordinate axis. The possible values are the names of the columns in the columns[] input port.

On

A toggle, located to the right of the Y Axis menu, that turns on or off the X coordinate axis. The default is off.

Z Axis

A menu from which you can choose the name of a column that will serve as the Z coordinate axis. The possible values are the names of the columns in the columns[] input port.

On

A toggle, located to the right of the Z Axis menu, that turns on or off the X coordinate axis. The default is off.

Axis Setup

A menu from which you can choose the name of a column whose axis parameter you want to set. This parameter value is used when you select the column as a coordinate axis.The possible values are the names of the columns in the columns[] input port.

Discrete

A toggle that specifies whether to use discrete or continuous coordinates on the axes. If selected (the default), discrete coordinates are used, otherwise continuous coordinates are used.

Continuous coordinates cannot be used with string values.

Field Data

A menu from which you can choose the columns that will become data components in the output scattered field. The first possible value is Count Records (see next parameter description); the other possible values are the names of the columns in the columns[] input port.

Data Setup

A menu from which you can choose the name of a column whose field data parameter you want to set. This parameter value is used when you select the column using Field Data. The possible values are the names of the columns in the columns[] input port.

sphere radius

A toggle that specifies whether the data in a column should be treated as sphere radii. If selected (the default), the data values in the column specified with Data Setup are put into a field with a special ID, and when visualized, the renderer treats the data as sphere radii.

Output Ports

out_fld

A scattered field with its data.

out_obj

A renderable field.

x_name

The name of the column selected as the X coordinate axis.

y_name

The name of the column selected as the Y coordinate axis.

z_name

The name of the column selected as the Z coordinate axis.

File

v/db.v

See also

• Read_Column_File
• table_to_uniform_field

 




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