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Using the Polygonise Tool in MapInfo Pro Advanced

MapInfo Pro 17.0, MapInfo Pro Advanced 17.0

MapInfo Pro Advanced provides a new established tool that takes a raster as an input and joins adjacent cells based on the selected polygonisation method. The output of polygonisation is a MapInfo TAB file that contains region objects.

Poylgonise Tool dialog:

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The tool provides the below four polygonisation methods to create regions:

Same Value Cells - Using this method polygons are created by connecting adjacent cells having same cell size. The values of the cells in the input raster are compared and all cells having same value are connected to form a polygon.

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Valid/Invalid - In this method, all adjacent valid cells are connected to form a polygon and similarly all invalid cells are connected together to form a polygon, regardless of the cell values.

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Raster Extent – A polygon is created around the extent of input raster using this method. This way, a polygon for the entire extent of input raster can be generated.

User Defined - In this method, a polygon is created around the user defined breaks or intervals. This method works on continuous raster only. The polygon is created by connecting cells with values falling in the defined range. The user defined range is divided into equal number of breaks. For example, in a continuous raster if the values are from 1 to 100 and the ‘Number of Intervals’ is defined as 4, the range is divided into 4. Polygons are created when any value falling into 1 to 25 range is found.

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There are following set options available for Same Value Cells and User Defined polygonisation method.

Match Colors to Input – With this option enabled, the resulting polygon can be filled with the color value of the cell. The polygons in the vector file will be colored using the color value of the cell.

Display Region Border Line –Polygons are closed lines which can be filled with a color, and further used for spatial queries.

 Intervals  

When User Defined option is chosen from the Method list, the Interval List appears.

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In this section, the polygon intervals can be previewed and their settings modified.  

Minimum - Enter the minimum cell value in the minimum field. The value below the specified minimum value will not be considered for polygonisation.

Maximum - Enter the maximum cell value in the maximum field, the cell values above the specified maximum value will not be considered for polygonisation.

Interval Method - Depending on the method selected, fixed or custom, the items in the drop-down list change.

Number - Specify the desired number in the Number field, if Number of intervals is selected. For example, if the input raster contains cell values between 1 to 100, and the number of intervals is specified as 5, it will result in 5 intervals with a spacing of 20 each.

Spacing - Specify the desired number in the Spacing field, if fixed spacing is selected. For example, if the input raster contains cell values between 1 to 100, and spacing of 20 will result in 5 intervals.

Output File

Output File - Using this option, edit the output file name and browse to save the output file in the system directory.

Display Output File - With this option the output in the mapper after the successful completion of the Polygonise operation can be displayed. It can be configured to make this default behavior from the Raster Preferences dialog.

Below is the supported input data field types that can be used while running different Polygonisation Methods:

Polygonisation MethodContinuousClassifiedImageryImage Palette
Same Value  User-added imageUser-added imageUser-added imageUser-added image
Valid/Invalid  User-added imageUser-added imageUser-added imageUser-added image
Raster Extent  User-added imageUser-added imageUser-added imageUser-added image
User Defined  User-added imageUser-added imageUser-added imageUser-added image
UPDATED:  May 2, 2018