Feature Tables
Like a pen table, a feature table changes the appearance of specified elements of a plot. This process is called resymbolization. Some common uses for resymbolization include the following:
- Highlighting specific elements by changing their color, width, or line style.
- Substituting the current date for a specified text string.
- Controlling the order in which elements print.
- Obtaining consistent colors on various plotters with the use of color tables and libraries.
- Defining custom line styles.
- Area-filling closed elements with a specified color or pattern.
- Omitting specific elements from the plot.
However, a feature table is not a sequence of instructions for testing and modifying elements. Instead, a feature table contains a series of feature descriptions that contain the following three parts:
|
Name: |
|
Identifies the element group |
| Definition: |
|
Identifies a group of elements sharing a set of characteristics |
| Symbology: |
|
Describes how those elements should appear on a plot |
How a Feature Table Works
The feature table is compiled on the client node and included in the metafile for execution on the server node. If an element possesses the characteristics listed in one of the feature definition sections, the modifications listed in the corresponding symbology section are made and no further processing is performed for that element. Otherwise, the element is not modified. The feature table does not modify the original design file or its reference files.
There are two feature table editors: IPLOT Feature Table Editor (MicroStation based) and APLOT Feature Table Editor (AutoCAD based).
Creating a Feature Table
The IPLOT Feature Table Editor can be invoked the following ways:
- Select IPLOT Feature Table Editor from the InterPlot Utilities program group.
- From the InterPlot Organizer interface, the General property page contains a New/Edit button that corresponds to the pen/feature table field. The New/Edit button invokes the IPLOT Feature Table Editor.
- From a Command prompt, type
ipfte feature_table_name and press Enter.
The APLOT Feature Table Editor can be invoked the following ways:
- Select APLOT Feature Table Editor from the InterPlot Utilities program group.
- From the InterPlot Organizer interface, the General property page contains a New/Edit button that corresponds to the pen/feature table field. The New/Edit button invokes the APLOT Feature Table Editor.
- From a Command prompt, type
apfte feature_table_name and press Enter.
Creating a feature table is essentially a two-step process. First, you must define a new feature using the Definition tab inside the Feature Table Editor. Second, after a new feature is defined, you can use the symbology tabs to determine how the elements will look when they are printed.
Defining a New Feature
- Select Edit > New Feature from the menu. A feature called New Feature is added to the features list.
- To rename the new feature, click the feature and type the new name or select Edit > Rename and type the new name.
- On the Definition tab page, click New Condition. Use the Comparison keyword list to distinguish the new feature from other features in the design file.
- If the new feature is a subfeature, use the list button on the Parent field to display a list of existing features. From the list, select the parent feature for the new feature.
- Select a valid relational operator for the selected comparison keyword.
- Select or type the value for the comparison keyword in the Value edit box.
- Add additional comparison keywords if needed.
Defining the Symbology
Feature symbology defines how elements look when they are printed. For each feature definition, there are 4 symbology tabs that can be modified:
Line Symbology: The Line Symbology page enables you to set the line symbology for the feature selected. Line symbology includes color, weight, endcap, translucency and other IPLOT/APLOT-specific line symbology settings.
Fill Symbology: The Fill Symbology page enables you to set the fill symbology for the feature selected. Fill symbology includes area fill, boundary display/color, fill color, pattern fill/color, and translucency.
Environment: The Environment page enables you to use environment variables in feature tables to perform text substitution and to extract data from the design file.
Other Symbology: The Other Symbology page enables you to set other symbology for the feature selected. Other symbology includes priority, inherit from parent and other IPLOT/APLOT-specific symbology settings.
Special Features
The Default Feature
The Default feature enables you to change the symbology of all elements not defined in the other features. The Default feature will always display in the tree, but will not be written to the file if it is empty. The Default feature cannot be deleted, moved, or renamed.
Value Mapping
Value Mapping enables you to map a comparison keyword to a specific assignment keyword. For example, since weight zero lines print as single pixel lines and the thickness varies depending upon the printer resolution, you may want to map line weights to a specific line thickness. Mapping weight to thickness ensures consistent line thickness across a wide range of printer resolutions.
Character Substitutions
The Character Substitutions command enables you to replace the string in a text element with a new string. By putting text elements in your design file to act as placeholders, you can later substitute these strings with useful information such as the date the file was plotted or the design file name.
Saving a Feature Table as a Pen Table
A feature table can be saved as a pen table but the new pen table cannot be converted back to a feature table. To save a feature table as a pen table, select File > Save As. The Save Feature Table As dialog will display. Change the "Save as type:" field to Pen Tables (*.pen). Enter the new pen table name in the "File name:" field and click Save.
Configuration Variables
IPLOT_FEATURE_TABLE_PATH = $IPLOT_MASTER_DIR;.
This variable gives the starting point for the IPLOT feature table file selection dialog box in the dialog interface and Organizer and the Save/Save As dialog in the IPLOT Feature Table Editor. The first directory listed in the appropriate search path is the starting point.
IPLOT_DLOG_FEATURE_TABLE_FILTER = "*.ftb"
This variable defines the filter that determines which filenames to display in the IPLOT feature table file selection box in the dialog interface and Organizer and the Save/Save As dialog in the IPLOT Feature Table Editor.
APLOT_FEATURE_TABLE_PATH = $APLOT_PEN_TABLE_PATH
This variable gives the starting point for the APLOT feature table file selection dialog box in the dialog interface and Organizer and the Save/Save As dialog in the APLOT Feature Table Editor. The first directory listed in the appropriate search path is the starting point.
APLOT_DLOG_FEATURE_TABLE_FILTER = aft
This variable defines the filter that determines which filenames to display in the APLOT feature table file selection box in the dialog interface and Organizer and the Save/Save As dialog in the APLOT Feature Table Editor.