Boundary File (.BNA) Format

Q: Can I create .BNA boundary files using digitized boundary information (latitude and longitude values)?

A: You can enter coordinate information manually using the Boundary File Editor in TAP, or you can create your own boundary files following the format described below.

The SoftWright plotting programs provide the capability of adding boundary information to plots generated with the Terrain Analysis Package (TAP) Ô system. This information can include political boundaries (counties, cities, etc.), functional boundaries (business district, target market areas, etc.), roads, site locations, etc.

The boundary line data files are ASCII files that are compatible with other software that recognizes the Atlas BNA format, such as Golden Software's MapViewerÔ and SURFERÔ programs, as well as Caliper's Maptitude.

Boundary line files for each state, including counties, roads and zip codes, are available from SoftWright. TAP includes an editor to conveniently edit the .BNA objects, as well as other programs for filtering and selecting boundaries from the TAP Graphic Window.

Boundary Objects

Boundary line files can contain three types of objects:

All boundary information in the file is represented by latitude/longitude pairs that define the end points of line segments (for lines and areas) or single point locations.

Boundary File Format

The boundary file information is saved in ASCII files using the same file format as described in Appendix C of the MapViewer manual from Golden Software. The file format is:


Coordinate values are indicated by decimal degrees of latitude and longitude. West longitudes and south latitudes are negative numbers to maintain normal plotting conventions (x values increase going right [east] and y value increase going up [north]).

Complex areas can include "islands." The coordinate pairs representing the islands are separated from each other by repeating the initial coordinate of the main area. The following sample file illustrates a complex area:

Boundary line files can be created and edited with an ASCII editor, or, more conveniently, with the TAP Boundary Line Editor program in the Boundaries menu.

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