MapInfo .mid/.mif format is widely used for interchange with MapInfo and other GIS applications. The format normally uses two files that have the same base name but with a .mif or .mid extension. The .mif file stores geometry information and the .mid file stores data attributes. If a .mid file is present Manifold will import the table of data attributes it contains.
When exporting, .prj and .mapmeta files are written. See the Exporting topic.
To import from MIF format:
Choose File-Import from the main menu.
In the Import dialog browse to the location of the file and double-click on the .mif file desired.
A table and a drawing will be created, with possibly a map and labels as well.
Importing the sample file shown in the dialog above results in a drawing and its table as well as a labels component for the drawing and a map.
The drawing shows property parcels as area objects.
In the illustration above we have used Style to format the drawing.
On import of a MapInfo MIF or TAB file, Manifold will translate MapInfo logical data type columns into Manifold boolean data type. Exporting a Manifold drawing to MIF will export Manifold boolean columns into MapInfo logical data type columns.
Writing to MIF format exports uint16 values as INTEGER and uint32 as FLOAT to avoid potential data loss. Writing to MIF format exports vector values and uuid fields as CHAR.
MapInfo MIF and TAB do not store the names of datums within the projection information stored in the file; instead, the numeric parameters for the datum are saved. When Manifold scans such a file the system will examine these numeric parameters to find a named datum that is a match.
In some cases, more than one datum may use the same numeric parameters. For example, there are many national datums that are mathematically identical to some generically named datums. When several datums match the given numeric parameters, Manifold will choose a neutrally named datum in preference to a name that uses a specific country name.
Coordinate systems - MIF files will often import with correct projection information but might not do so depending on the vintage of the MIF file. Be ready to gather any notes or metadata from the source of the MIF files that may specify the projection in use. If need be, immediately launch Assign Initial Coordinate System in the Component tab of the Info pane to specify the correct initial projection for the imported drawing.
Unique field names - Due to encoding issues, some MIF files may use duplicate field names. Imports will accept such duplicate field names, but will adjust them to make each name unique.
Assign Initial Coordinate System