2011

Table Of Contents
SDF version 2 is still supported by MapGuide 6.5 (and earlier releases), and
AutoCAD Map 3D can import and export SDF 2 using a separate import/export
interface.
Advantages
SDF has the following advantages over DWG:
It stores and manages an order of magnitude more data than DWG
It is very fast, allowing Autodesk applications, such as AutoCAD Map 3D
and MapGuide, to read and display tens of thousands of features per second.
It provides the power of a database without the overhead and cost of a full
relational database management system (RDBMS) such as SQL Server or
Oracle.
An SDF file can store a single feature class, or it can store multiple feature
classes.
It is easy to manage, providing access to the database schema.
Exporting
If you export to an existing file, you can choose to overwrite that file or append
the new data to it. Overwriting destroys the existing file and creates a new
one. Appending adds the data in the current export operation to the existing
data without deleting any existing data.
When you append, any existing classes in the target file remain unchanged.
New feature classes and new properties for existing feature classes will be
added.
If the target file contains properties for which the source file has no values,
the resulting file may show those properties as being null or as having default
values, depending on what was specified in the schema.
If the source data contains classes that are not in the target file, those classes
will be created and will have the properties of the source data.
NOTE An index property is added to each feature class when you export. You can
specify the name for this property in the
MapExport.ini file (page 264).
A message reports on the export results. Because some entities belong to
multiple feature classes, the number of entities exported may not match the
number of SDF entities created. The message tells you how many DWG entities
were exported more than once. If you base the exported feature classes on
1414 | Chapter 9 Publishing and Sharing Maps