Region, Line, and Point type objects from a BNA file are supported. Circles are ignored and not imported.
A BNA object must have at least one identifier, and can have up to three identifiers. Each object must have the same number of identifiers, even if they are blank strings. In BNA parlance, the identifiers are called NAME, NAME2, and ID, and are presented in that order in the file.
Following the identifiers is a number representing the type and length of the object. In all cases, the number itself represents the number of points that make up the object.
Regions have at least four points, lines at least two, and points may only have one. To identify an object as a region versus a line, regions use a positive number, while lines are identified by a negative number.
In a BNA file, latitude/longitude coordinates must be represented in decimal degrees, with up to six decimals of precision. Longitude is the x coordinate, and latitude is the y coordinate. Western longitudes and southern latitudes are always negated. This means that for the U.S., longitudes should be negated, while latitudes should be positive. User coordinates should be entered as whole numbers, as the decimal portion is ignored.
Only BNA files that are delimited with commas are supported. All identifiers should be quoted. Each feature in a BNA file is made up of several lines of information. These lines should be formatted as shown in the examples. The format just described is used by ESRI's Atlas Import/Export product, which creates BNA files.
The basic format for objects in a BNA file is as follows:
"NAME", "NAME2","ID", type/length
x1, y1
x2, y2
.
.
xn, yn
"Next object",""," ", type/length
x1, y1
.
.
xn, yn