The MapInfo Interchange File (MIF)
Format Specification
MapInfo Corporation
Troy, NY
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MapInfo Interchange File (MIF) Format Specification
October 1999
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Introduction
This specification provides information about the MapInfo Interchange File (MIF) format. MIF is an ASCII text file format that fully describes the contents of a MapInfo table. MIF consists of two related files: one for the graphical data, and one for the tabular data. The graphical data is in a file with a .mif extension, and the tabular data is in a file with a .mid extension. MIF files can be read and written by MapInfo Professional and translated into other formats with other programs. In this guide, you will find information on:
Chapter 1: MapInfo Data Interchange Format
•MIF File Header
•MIF Data Section
•Pen Styles
•Brush Styles
•Symbol Styles
•Font Styles
•Colors
•MID File
Chapter 2: Creating Your Own Coordinate System
•Projections and Coordinate Systems
•Elements of a Coordinate System
•Editing the MAPINFOW.PRJ File
•Affine Transformations
•Frequently Asked Questions on Projections
•More Information on Projections
Chapter 1: MapInfo Data Interchange Format
This chapter describes the data interchange format for MapInfo. In this chapter, you will find information on:
•MIF File Header
•MIF Data Section
•Pen Styles
•Brush Styles
•Symbol Styles
•Font Styles
•Colors
•MID File
This versatile format allows generic data to be attached to a variety of graphical items. Since it is ASCII, it is editable, relatively easy to generate, and works on all platforms supported by
MapInfo. Perhaps the best way to understand the MapInfo Interchange Format (MIF) is to
study the sample file at the end of this chapter in conjunction with the explanation of the file format. You can also create samples of your own by exporting files to MIF and then examining those files in a text editor.
MapInfo data is in two files - the graphics reside in a .MIF file and textual data is contained in
a .MID file. The textual data is delimited data, with one row per record and either Carriage
Return, Carriage Return plus Line Feed, or Line Feed between lines. The MIF file has two
areas - the file header area and the data section. Information on how to create MapInfo tables is in the header; the graphical object definitions are in the data section.
MIF File Header
This is a description of MIF file header with optional information in square brackets.
VERSION n
Charset ”characterSetName”
[ DELIMITER ”<c>” ]
[ UNIQUE n,n.. ]
[ INDEX  n,n.. ]
[ ]
[ ]
COLUMNS n
<name> <type>
<name> <type>
.
.
DATA
Chapter 1: MapInfo Data Interchange Format
Version
The Version clause states whether you are using VERSION 1, VERSION 2, VERSION 300 or VERSION 450 of the format. Version 300, introduced with MapInfo 3.0, allows multiple–section polyline objects. VERSION 450 introduced the expanded node limit: the maximum number of nodes for regions and polylines is 1,048,572 nodes for a single polygon region or polyline. The limit drops by seven nodes for every two additional polygons.If an object with more than 32K nodes is saved and the table is read in a version of MapInfo prior to version 4.5,  the object(s) will not be visible. Objects in the table that do not exceed the 32K limit will be visible. VERSION 450 also includes point sized pen width.
Charset
The Charset clause specifies which character set was used to create text in the table. For example: Specify “WindowsLatin1” to indicate that the file was created using the Windows US & Western Europe
character set; specify “MacRoman” to specify the Macintosh US & Western Europe character set; or specify “Neutral” to avoid converting the text into another character set. If you are not using one of these character sets, you can determine the correct syntax for your character set by exporting a table and examining the .MIF file in a text editor.
Delimiter
Specify the delimiting character in quotation marks, for example:
DELIMITER ”;”
The default delimiter is Tab; if you are using the default, you do not need the DELIMITER line.
Unique
Specify a number. This number refers to a database column; 3 is the third column, 7 is the seventh column, and so forth. What happens to columns in the UNIQUE list is subtle. For example, imagine that you have a database with highways in it. Each highway has only one name, but it might be represented by several segments. You would put the NAME column in the UNIQUE list, while the column containing data for the individual segments would not be in that list. This has the effect of creati
ng two related tables; one with names, and one with the other attributes of the objects. This is how MapInfo’s various street maps (StreetInfo) are prepared.
3
Chapter 1: MapInfo Data Interchange Format
4Index
To indicate that columns in the table are indexed, include a number (or a comma–separated list of numbers) in the Index clause. Each number refers to a database column; 3 is the third column, 7 is the seventh column, and so forth. Columns in the INDEX list will have indexes prepared for them.
CoordSys Clause
Specify the COORDSYS clause to note that the data is not stored in longitude/latitude form. When no COORDSYS clause is specified, data is assumed to be stored in longitude/latitude forms.
All coordinates are stored with respect to the northeast quadrant. The coordinates for points in the United States have a negative X while coordinates for points in Europe (east of Greenwich) have a pos
itive X. Coordinates for points in the Northern hemisphere have a positive Y while coordinates for points in the Southern hemisphere have a negative Y.
Syntax1
CoordSys Earth
[ Projection type,
datum,
unitname
[ , origin_longitude]
[ , origin_latitude  ]
[ ,  standard_parallel_1[ , standard_parallel_2]]
[ , azimuth ]
[ , scale_factor ]
[ ,  false_easting ]
[ , false_northing]
[ , range]]
[ Affine Units unitname, A, B C, D, E, F ]
[ Bounds ( minx, miny) ( maxx, maxy) ]
Syntax2
CoordSys Nonearth
[ Affine Units unitname, A, B C, D, E, F ]
Units unitname
Bounds( minx, miny) ( maxx, maxy)

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