The MapInfo Data Interchange Format (MID/MIF) profile is specified in the Geomatics Canada document titled Conversion of NTDB Edition 3 Data into MID/MIF Format. This profile has the following properties:
- NTDB entities are written to output files organized by theme. The name of the output file combines the NTS mapsheet number with the theme abbreviation. The table below summarizes the list of themes and their abbreviations.
NTS Mapsheet Themes, Abbreviations, and Numbers
|
Theme Name |
Abbreviation |
Theme number |
|
Designated areas |
AD |
0 |
|
Roads |
CH |
1 |
|
Man-made features |
CO |
2 |
|
Relief and landform |
FO |
3 |
|
General |
GE |
4 |
|
Hydrography |
HD |
5 |
|
Hypsography |
HP |
6 |
|
Power network |
RE |
7 |
|
Rail Network |
RF |
8 |
|
Road network |
RR |
9 |
|
Water saturated soils |
SS |
10 |
|
Toponymy |
TO |
11 |
|
Vegetation |
VE |
12 |
- Each dataset in a physical volume occupies a folder identified by the NTS number.
- The output coordinate system for NTDB is a UTM system with a NAD83 datum, coordinates in metres, and a scale factor of 0.9996.
- The output file contains at a minimum the following attributes:
- CODE (explicit code)
- ATTF
- ELEVATION
- ORIENTATION
- ATV1_ACCURACY
- Other attributes are named ATFn_<attribute_name> and ATVn_<attribute_name>.
- A MapInfo symbol table is used to represent explicit codes.
Some of these conventions are difficult to follow with an automatically generated mapping file, especially considering the variety of output formats available. Even for MID/MIF output, however, FME cannot completely adhere to all conventions without involving manual editing of the generated mapping file.
The FME’s approximation to the above conventions are as follows:
- The profile specification calls for output files that correspond to FME feature types to have names including the NTS map number. Unfortunately, the 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 is necessary to modify the generated mapping file to include the map number as a part of the output feature type names.
- Where possible with the choice of output formats, the attributes are defined as described above. Additional attributes 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 MID/MIF profile, a source format specification of ntdbcm, which is an abbreviation of NTDB CCOGIF to MID/MIF, is used. An example of how this is written is:
fme generate ntdbcm ...