Detailed description of MapInfo File Format

Detailed description of MapInfo File Format

In Mapinfo, each map is called a layer (or table ).
Each MapInfo table consists of two most important parts: Graphs (called spatial objects) and data (called attributes ).
MapInfo
One-to-one connection between "graphic objects" and "attribute data" is implemented to query graphic data and attribute data in two directions. MapInfo supports attribute-based Quick query.
Field to create an index. MapInfo stores the preceding information in different files as files to form a complete layer. Where
* The tab defines the table structure, which is used to save the table field name and field type;
*. MAP is used to store graphic data;
*. Dat is used to store the attribute information of a map object;
*. ID is used to save the one-to-one correspondence between map objects and attribute records;
*. Ind stores the index relationships created based on Attribute fields. If you cancel an index on any field, MapInfo automatically deletes this file .)
Some of the above files can be opened in the text editor to view the specific content.

Description: MapInfo index file *. Ind:
Each MapInfo table consists of several files. Different files are used to save different information of layers. Where, *. Ind
File is used to store the data index of the Mapinfo table. It is the index file of the Mapinfo table, which can improve the efficiency of MapInfo data retrieval. It also allows you to use the "Search" command to search for maps.
Object. If you use the search command to locate an address (city), you must create indexes for these cities in the table, and these indexes are saved in the *. Ind file.
After you create an index for a layer, MapInfo automatically generates an index file *. Ind. After you cancel the index of a layer, MapInfo automatically deletes the index file *. Ind.

-- MIF, mid format --------------------------------------------------------------------------------------------------------------

Although MapInfo does not disclose its internal data structure, it provides a data structure for format exchange, that is, MIF and MID. In this example, the MIF File Stores graphic data and the mid File Stores
Attribute data. Convert the map data of other forms to the format of MIF and MID. Then, use the import command in the Mapinfo menu to import the map data to complete the conversion. You can also
In Mapinfo, convert *. Tab file to *. MIF, *. Mid File

MIF is an intermediate exchange file used by MapInfo to exchange data externally. After you transfer a MapInfo chart in MapInfo format to the MIF file, MapInfo generates two files (*. MIF ,*. mid ).
The *. MIF file stores the table structure of the Mapinfo table and the space information of all the space objects in the table:
Coordinates and symbol styles of each vertex object;
Number of nodes, node coordinates, and line style of each line object;
Number of sub-regions included in each region object, number of nodes in each sub-region, node coordinates, and fill Mode
The *. Mid file stores all attribute information of each space object in record order.
These two files are all text files. You can use the corresponding file read/write method to read and write the file content.