Boundary File Filters

Boundary File Filters - Names

Q: I don’t want to plot the entire state boundary file with my relatively small coverage area. How can I plot just a part of the file with the counties I want?

A: The TAP Map Window plotting allows you to plot boundary files you select. If you want to plot only part of a file, you can use one of the boundary filter programs to create a new file containing only the objects you want to plot. (With the Map Window, you could plot the entire file, then use the zoom features to show and print only the area of interest. However, using the boundary filter programs will allow you to save time and disk space for the drawing file.)

Several filter options are available, depending on what you are trying to do. You can filter by:

Distance from a point

Latitude/longitude rectangle

An arbitrary polygon

The names of objects in the file

This document describes using the filter by names program.

Filter by Names

Suppose you want only selected boundaries from a boundary file. From the TAP Boundary menu, select "Filter by Name".

This will display the Name Filter form.

Enter the boundary file you want to read and filter. You can also click the "Browse" button to select a file

Enter the name of an output .BNA file where you want to write the results. (You can also use the "Browse" button to find an existing path and/or file.)

Click the "Open" button to open the input file.

The first object in the file will be displayed, showing the .BNA file Primary ID and Secondary ID, separated by a "|" character. The number of points in the object is also shown.

If you want to write the object shown to the output file, click the "Write" button. For this tutorial, click the "Write" button to include Adams county in the output file.

When the "Write" button is clicked, the current object is written to the output file, and the next object in the input file is displayed:

To move to the next object in the file, click the "Next" button. For this tutorial, click the "Next" button to skip Alamosa county and not write it to the output file.

Note that it is not possible to move backwards in the file with this program. If you need to move to an object earlier in the file you can click the Input File Close button (located next to the "Open" button) to close the file, then re-open the file. The first object in the file will then be displayed. Note also that the order of the objects in the file is the order displayed, not alphabetically.

The description information for the next object will be displayed. For this tutorial, click the "Write" button to include Arapahoe county.

You can also search for a specific object description in the file. For example, enter "Denver" in the "Find" text box. (Note that case is ignored.)

Click the "Find" button:

If an object with the specified string in either the Primary or Secondary ID is found, that object is displayed.

For this tutorial, click the "Write" button to include Denver county.

When you have completed your selections, click the "Close" button.

To view the file you just created, select "New Map" from the TAP File menu:

On the Coverage Plot form, click the "Boundaries" button:

Find the path and file you just created, then click the "OK" button:

The file will be displayed in the boundary file list.

Double click the line showing the file to display the Layer Properties form. (This form is used for setting colors, etc., and is discussed in more detail elsewhere.) Be sure the "Show Text" box is checked:

Click the "Close" button on the Layer Properties form:

Click the "Continue" button on the Map Window Boundary Files form:

On the Coverage Plot form click the "Plot" button:

The filtered boundary file will be displayed, showing only those counties you selected.