The DXF profile is specified in the Geomatics Canada document titled “Conversion of NTDB Edition 3 Data into DXF Format”. This profile has the following properties:
- The data is written to a DXF file for each theme. The themes are the same thirteen themes as those used for the MID/MIF profile.
- The file names for the theme files are <nts><abbrev>.dxf where <nts> is the NTS map number and <abbrev> is the lower-case equivalent of the theme abbreviation listed in the above-mentioned table.
- Entities are stored in layers named <entityName>_<explicitCode> where <entityName> is the first 11 or fewer characters of the NTDB entity name and <explicitCode> is the explicit code of the entity.
- Fixed attributes—ATFn_<attrName>—are not stored with the features. Their values are implied by the explicit code.
- Except for toponymy, variable attributes are not transferred to the DXF features.
- There is no area under DXF.
Some of these conventions are difficult to follow with an automatically generated mapping file, especially considering the variety of output formats available. Even for DXF output, however, FME cannot completely adhere to these rules without involving manual editing of the generated mapping file.
The FME’s approximation to the above conventions are given here:
- FME considers the target dataset of a DXF file to be the file itself, so it is not possible to generate a number of themes’ output files from a single run of FME. To accomplish this, you would have to run the same CCOGIF file through the mapping file for each desired themes. Refer to the discussion under the heading Theme Selection for more details.
- The profile spec calls for output files that correspond to FME feature types to have names including the NTS map number. Unfortunately, FME mapping file generation process cannot use a variable name for the output feature types, therefore it generates all mapping files with output feature types of NTSNUM_<themeAbbrev>, where <themeAbbrev> is a theme abbreviation from NTS Mapsheet Themes, Abbreviations, and Numbers. It will be necessary to modify the generated mapping file to include the map number as a part of the output feature type names.
- When possible with the choice of output formats, the attributes are defined as described above. Additional attributes will take either the English or French name of the corresponding CCOGIF attributes, depending on the setting of NTDB_Language.
To generate a mapping file for the DXF profile, a source format specification of ntdbcd, an abbreviation of NTDB CCOGIF to DXF, is used. An example of how this is written is:
fme generate ntdbcd ...