BNA - Atlas BNA

The BNA format is an ASCII exchange format for 2D vector data supported by many software packages. It only contains geometry and a few identifiers per record. Attributes must be stored into external files. It does not support any coordinate system information.

OGR has support for BNA reading and writing.

The OGR driver supports reading and writing of all the BNA feature types :

As the BNA format is lacking from a formal specification, there can be various forms of BNA data files. The OGR driver does it best to parse BNA datasets and supports single line or multi line record formats, records with 2, 3 or 4 identifiers, etc etc. If you have a BNA data file that cannot be parsed correctly by the BNA driver, please report on the GDAL track system.

To be recognized as BNA, the file extension must be ".bna". When reading a BNA file, the driver will scan it entirely to find out which layers are available. If the file name is foo.bna, the layers will be named foo_points, foo_polygons, foo_lines and foo_ellipses.

The BNA driver support reading of polygons with holes or lakes. It determines what is a hole or a lake only from geometrical analysis (inclusion, non-intersection tests) and ignores completely the notion of polygon winding (whether the polygon edges are described clockwise or counter-clockwise). GDAL must be built with GEOS enabled to make geometry test work. Polygons are exposed as multipolygons in the OGR Simple Feature model.

Ellipses and circles are discretized as polygons with 360 points.

Creation Issues

On export all layers are written to a single BNA file. Update of existing files is not currently supported.

If the output file already exits, the writing will not occur. You have to delete the existing file first.

The BNA writer supports the following creation options (dataset options):

VSI Virtual File System API support

(Some features below might require OGR >= 1.9.0)

The driver supports reading and writing to files managed by VSI Virtual File System API, which include "regular" files, as well as files in the /vsizip/ (read-write) , /vsigzip/ (read-write) , /vsicurl/ (read-only) domains.

Writing to /dev/stdout or /vsistdout/ is also supported.


The ogrinfo utility can be used to dump the content of a BNA datafile :
ogrinfo -ro -al a_bna_file.bna

The ogr2ogr utility can be used to do BNA to BNA translation :

ogr2ogr -f BNA -dsco "NB_IDS=2" -dsco "ELLIPSES_AS_ELLIPSES=NO" output.bna input.bna

See Also