Parent Topic: Supported File Formats

Arc/Info Import/Export (E00)

Arc/Info Import/Export files in the form of a E00 (Data Interchange File) file are supported by the GeoGateway library for read or write operations. The three level of file compression are supported for reading (NONE, PARTIAL and FULL) and new E00 files are always generated with no compression.

When reading, various layers are available depending on what is found in the E00 file (at most one of each type):

ARC: Arcs, with attributes from AAT section
PAL: Polygons, with attributes from PAT section
NAT: Nodes Attributes Table
LAB: Labels, with attributes from PAT section
CNT: Centroids
TX6: Text

Most Arc/Info projections are supported.

Both single and double precision E00 files are supported. The default for creating new E00 files is double precision. This default can be overwritten by using the options string "SINGLEONLY" to create single precision E00 files.

INFO tables are also made visible in separate layers. Any table that is not linked to one of the layer types above will appear as a secondary table in a separate layer.

If clean topology is present in the file, then the topological layers will contain some special MetaData members.

Export of Arc/Info Import/Export files is supported. These files are exported with a type of "AII".

When writing, GeoGateway defaults to create non-topological E00 files, but applications that support GeoGateway Topology can create E00 files that contain clean Arc/Info topological coverages.

Applications that do not support topology (such as FEXPORT and most PACE programs) will create simple E00 files without topology and either:

An ARC section and an associated .AAT INFO table. This is the default behaviour. Also setting the create option string to "ARC" when creating the file or layer will create an ARC section.
A point coverage with a LAB section and an associated .PAL INFO table. Point coverages are generated when the LAYER_TYPE metadata value is set to "POINTS" when the output layer is created or if the create option string is set to "POINT".

Applications that support topology can provide a set of topological layers with clean topology and this will result in a E00 file with complete topology. If the set of layers contained an area layer, then a CNT and a LAB section will automatically be generated to accommodate the Arc/Info topology requirements. GeoGateway also recomputes the values for the arc's LENGTH attribute and the polygon's AREA and PERIMETER attributes.

**NOTE**: In the current version, automatically generated labels are placed on the polygon's centroid location (gravity centre) which does not necessarily lie inside the polygon. This will be fixed at some point in the future.

In addition to the above, all E00 files generated include:

Projection, if one was provided.
TOL (tolerances) section, with default values.
.BND (bounds) INFO file containing coverage extents.
.TIC (registration control points) INFO file with 4 TICs corresponding to the 4 corners of the coverage.