MapInfo TAB format

MapInfo TAB

Filename extension	.tab
Developed by	MapInfo
Type of format	GIS

The MapInfo TAB format is a popular geospatial vector data format for geographic information systems software. It is developed and regulated by MapInfo as a proprietary format.

File components

The basic file components for a MapInfo Professional data set are established by the two basic environments for working in Mapinfo; "Browser view" and "Mapper View".

As with most other GIS packages, several files are required to allow the user to open a data set for viewing within Mapinfo Professional. The most basic view would be the browser view only. This environment provides storage of attribute or object data and is represented like a spreadsheet. Only data can be seen in a tabular format with this environment, no geographic information is available at this point.

Minimum files required for the basic Mapinfo browser environment:

• .DAT (The file that stores the attribute data. This usually a dBase III DBF file)
• .TAB (The ASCII file that is the link between all other files and holds information about the type of data file )

To view geographic information (the graphic representation of data) in Mapinfo Professional, two additional files are required and added to the basic requirements for simply viewing data.

Minimum files required to view a map with the data previously discussed:

• .ID (Stores information linking graphic data to the database information. This contains a 4-byte integer index into the MAP file for each feature)
• .MAP (Stores the graphic and geographic information needed to display a map on the users screen)
• .IND (Optional index files for tabular data. This is present if any fields are indexed).

So, one could say, the basic file set for viewing data and its graphic representation within Mapinfo Professional requires a minimum of four files, the *.DAT, *.TAB, *.ID and *.MAP

If you have only textual information and there are no graphic objects, then a minimum of two files is needed, *.DAT and *.TAB. If one opens, *.TXT, *.XLS *.WK*, *.MDB, then MapInfo creates a .TAB file that contains the definition of file, and data structure, so next time one can open the TAB file only.

There are also temporary files created by MapInfo while there are some edits on the file. Those are

• .TDA Temporary database file
• .TIN Temporary index file
• .TMA Temporary Map File

When using a remote table such as Oracle Locator or Spatial, if the data is downloaded to the local machine, the temporary file extensions are:

• .LDA Local Temporary database file
• .LIN Local Temporary index file
• .LMA Local Temporary Map File

If MapInfo halts or in case the edited changes are not saved and the power is gone, those files remain in the computer.

External links

• MITAB - MapInfo .TAB Read/Write Library