11.2. The MIF file

11.2. The MIF file
	Chapter 11. Geometry input


	The information in this section is essentially based on the MapInfo Data Interchange Format document [2].

Geographical units are described in an ASCII file by their X and Y coordinates. The .MIF file is made of an header section then a data section.

Figure 11.1. MIF file header

VERSION n
Charset ”characterSetName”
[ DELIMITER ”<c>” ]
[ UNIQUE n,n.. ]
[ INDEX   n,n.. ]
[ COORDSYS...]
[ TRANSFORM...]
COLUMNS n
  <name> <type>
  <name> <type>
  
  etc.

As shown on Figure 11.1, the header can contain the following information:

VERSION: the version of the MapInfo software;
CHARSET clause specifies which character set was used to create text in the table (examples: WindowsLatin1, MacRoman or Neutral;
DELIMITER shows the character that is used to separate columns values (if not specified, tabulation is the default delimiter);
UNIQUE parameter must be a number that refers to a database column, this parameter is used to create related tables;
INDEX parameter (a number or a comma-separated list of numbers) that shows the number(s) of the indexed column(s);
the COORDSYS parameter sets the used coordinate system.
This parameter is essential, in particular to compute the scale of the map. By default (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 West of Greenwich have a negative X while coordinates for points in the East of Greenwich have a positive X. Coordinates for points in the Northern hemisphere have a positive Y while coordinates for points in the Southern hemisphere have a negative Y. Examples:
- The following example represents a map of Europe centered on 50°N 15°E with a Lamber Azimutal projection that can be associated to the following bounds pair: (X_min, Y_min) (X_max, Y_max). The "m" option stands for "meters" as the unit:
```
CoordSys NonEarth Units "m" Bounds (-2217175, -1723801) (1783333, 2518193)
```
- Another setting for a map of Rhône-Alpes may be:
```
CoordSys NonEarth Units "m" Bounds (691594, 1893320) (993392, 2185448)
```
TRANSFORM parameter can be used to convert coordinates which are given in a different quadrant than the default northeast one.
COLUMNS parameter describes the data in the table of the associated MID file. The n parameter specifies the number of columns. Example:
```
Columns 1
   unit		Char(100)
```
specifies one column named unit, each value will be made of characters string type whose length is not longer than 100.

HyperAdmin is quite sensible on the format of the header of the MIF file (one information by line). Here are some examples of the expected formats for the header of the more frequently recent and used MIF files:

European datasets (used for ESPON HyperAdmin maps with the EPSG 3035 Coordinates system and projection):

Version 300
Charset "Neutral"
Delimiter ","
CoordSys NonEarth Units "m" Bounds (2600301.93555, 1249109.375) (6593124.61973, 5455935.88672)
Columns 1
  ID Char(50)
Data

(...)

EUROMED dataset:

Version 300
Charset "WindowsLatin1"
Delimiter ","
CoordSys NonEarth Units "m" Bounds (-4487557.26071, -3722255.38453) (4487557.26071, 2869559.87636)
Columns 1
  ID Char(10)
Data

(...)

Metroborder dataset:

VERSION 300
Charset "WindowsLatin1"
DELIMITER ";"
COORDSYS NonEarth Units "m" Bounds (-743051.308162917,-145654.445989655) (-537023.603469758,123325.733156574)
COLUMNS 1
     SHN Char(14)
DATA

(...)

The DATA keyword specifies both the end of the header of the MIF file and the start of the enumeration of outlines.

If the MapInfo MIF file may set different types of graphical primitives (point, line, polyline, etc.), the HyperAdmin software only expects the polygon type in order to describe the outlines of territorial units. Eeach TU whose identifier is given in the MID file (see Section 11.1) must be associated to a new entry in the MIF file under the data section, IN THE SAME ORDER, as a Region entry. In MapInfo, a Region object consists of one or more polygons. Let us describe an expected Region entry using the definition example shown on Figure 11.2.

Figure 11.2. Example of two "Region" entries in the MIF file Data section

Data
Region  2 
  7 
108071.871 -293320.749
96339.456 -282096.297
102833.097 -261179.193
106485.534 -258631.56
123883.98 -262981.491
122621.886 -282959.13
108071.871 -293320.749
    Pen (1,2,0) 
    Brush (0,1)
    Center 110111.718 -275976.153
  5 
-407753.01 -311500.065
-417000.993 -311417.496
-411718.965 -289228.641
-406514.985 -302217.573
-407753.01 -311500.065
    Pen (1,2,0) 
    Brush (0,1)
    Center -411757.989 -300364.353
Region  1 
  11 
2186917.593 -1518464.703
2186829.009 -1692861.786
2129979.423 -1729141.275
1933829.46 -1729141.275
1928265.747 -1699690.677
1922979.324 -1671615.192
1928499.903 -1666190.274
1941660.768 -1656068.01
2005909.794 -1679948.187
2047505.1 -1676110.68
2186917.593 -1518464.703
    Pen (1,2,0)		
    Brush (0,1)
    Center 2140313.457 -1623802.989

	Start of the entry for the first territorial unit in our data section. This region definition will be associated to the identifier on the firts entry of the `MID` file. The `2` parameter near `Region` shows that this region is made of two polyogons (example, France may be considered as a region made of two polygons: metropol and Corse island).
	The first polygon of this region is set with seven points whose coordinates in X Y forms are given on following lines.
	Pen(a, b, c), Brush(a, b) and Center x y specifications are optional and they will not be read by HyperAdmin.
	The second polygon of this region is defined with five points whose coordinates are given on the five following lines.
	Here is the start of a new `Region` definition. As the second entry of the data section, this region definition will be associated to the identifier on the second line of the `MID` file. `Region 1` indicates that this region is made of one polygon.
	This line shows the number of points that compose the polygon: 11 points, whose coordinates are successively given on 11 folloging lines.


11.1. The MID file		11.3. Layer of main cities