Skip to Content
Web Mapping Illustrated
book

Web Mapping Illustrated

by Tyler Mitchell
June 2005
Beginner to intermediate
372 pages
10h 1m
English
O'Reilly Media, Inc.
Content preview from Web Mapping Illustrated

Name

Microstation Design Files (DGN)

Synopsis

These are also known as DGN files.

File listing

Data is encapsulated in a single file, usually with the suffix .dgn; for example: 0824t.dgn.

Data access/connection method

  • Access is available in MapServer through OGR.

  • The CONNECTIONTYPE OGR parameter must be used.

  • The path to the dgn file is required; file extension is needed.

  • All types of features in a DGN file are held in one "layer" of data. The layer is called elements and is the first and only layer.

  • The type of feature to be read from the DGN depends on the TYPE parameter in the map file.

  • DGN files typically contain POINT, LINE, POLYGON, and ANNOTATION feature types.

  • DGN files contain "styling" information, i.e., how to color and present the data. This is used, optionally, by specifying the STYLEITEM "AUTO" parameter.

    Warning

    DGN files typically use white as a color for their features and therefore aren't visible on maps with white backgrounds.

ogrinfo examples

Using ogrinfo on a single DGN file

Note that no geometry/feature type for the layer is identified because it can be multiple types.

                     > ogrinfo /data/dgn/0824t.dgn
    Had to open data source read-only.
    INFO: Open of '0842t.dgn'
    using driver 'DGN' successful.
    1: elements

Using ogrinfo to examine the structure of the file/layer

DGN files aren't really GIS data files. They evolved from drafting formats used by computer-aided drafting/design (CADD) programs.

They carry a few key attributes that are usually consistent across all DGN files. Most of the ...

Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
and much more.
Start your free trial

You might also like

Flask Web Development, 2nd Edition

Flask Web Development, 2nd Edition

Miguel Grinberg

Publisher Resources

ISBN: 0596008651Supplemental ContentErrata Page