ImportBNA()

Argument

Contents

filename

The path and file name of the file to import

new_db_name

The path and file name of the new geographic file

layer_type

The type of features to import: Point, Line, or Area

table_name

The path and file name of the new table file

n_names

The number of name fields for each entity, as returned by GetBNAInfo()

Option

Type

Contents

Label

String

A descriptive label for the geographic file

Layer Name

String

The name of the layer in the geographic file

Median Split

Boolean

If "True" special handling insures that entities which cross the 180 degree longitude line are imported properly; if "False" (the default), no special handling is invoked

NAD Conversion

3 strings

Input datum, output datum, and conversion file (if needed); the input and output datums should be different

Node Layer Name

String

The desired name for the endpoint layer (only when importing a line layer)

Optimize

Boolean

Whether to optimize the geographic file automatically after the import (defaults to "True")

Overlap

String

Describes what to do with areas that overlap; takes one of the following values:

"Ignore" - Leave overlaps as-is and simply create a non-topological database, possibly containing overlapping areas

"Merge" (the default) - Where two areas overlap, merge the intersection into one of them; which one is arbitrarily decided

"New" - Create a new area where the two areas overlap

Projection

String, array

The projection name and the array of options

Tab Delimited

Boolean

Indicates whether the file is tab-delimited, as returned by GetBNAInfo

Topology

Boolean

For area layers, a value of "True" indicates that the resulting geographic file should have true area topology, which involves substantial complex processing. A value of "False" means that boundary edges can be duplicated, so that larger files can be imported. This option does not apply to point and line layers

Transform

Array

Array indicating the transformation to apply to coordinates in the file. This can have three forms:

1. An array of two or more four-element arrays containing local and world coordinates for control points, for example, {{real localX1, real localY1, real longitude1, real latitude1}, ...}

2. An array of four elements - {real X_multiplier, real Y_multiplier, real X_offset, real Y_offset}

3. Center and Extent transform {c1_x, c1_y, width_1, c2_x, c2_y, width_2}where center is shifted from (c1_x,c1_y) to (c2_x,c2_y), and vector of length width_1 out of c_1 becomes a vector of length width_2 out of c_2.

Error Type

Meaning

NotFound

There is no file by this name, or there are no entities in the designated layers of the desired type

Error

The file is not a valid BNA file

Function

Summary

GetBNAInfo()

Collects summary information on the contents of a BNA file