How to create attribute maps

In ILWIS for Windows, you can create attribute maps of raster maps, polygon maps, segment maps and point maps. The original maps have a Class or ID domain. An attribute table is usually linked to the map or to the domain of the map. The table uses the same domain as the map and stores additional information for each class or ID in the map in attribute columns. For more information on creating an attribute table, see How to create an attribute table.

By creating an attribute map, every original class name or ID in the map is replaced by an attribute value, class or ID as found in an attribute column in the attribute table; the geometry of the original map remains.

Example:

In this example, an attribute map is created for the acreage of cash crops (ha).

Input map:	Input attribute table:

Output attribute map:

There are two general methods to obtain an attribute map:

Open the map which has an attribute table: in the Display Options dialog box of the map, select the Attribute check box and select an attribute column from the attribute table. This results in a 'temporary' attribute map displayed in a map window. For more information, refer to How to display a map by one of its attributes.
Perform one of the Attribute Map operations on a map that has an attribute table. This results in a 'permanent' attribute map stored on disk. Methods to access the Attribute Map operations are described below. When you edit the attribute table and change attribute values, you can make the output attribute map up-to-date by clicking the Make Up-to-Date button in the Properties dialog box of the output attribute map.

Attribute Map of a Polygon Map operation

By creating an attribute map, each polygon class name or ID in the original map is replaced by the value, class name or ID found in a certain column in the attribute table.

To create an attribute map of a polygon map:

from the Operations menu in the Main window, choose Vector Operations and select Polygons, Attribute Map, or
in the Operation-tree, open the Vector Operations, Polygons item, and double-click the Attribute Map of Polygon Map item, or
in the Operation-list, double-click the Attribute Map of Polygon Map item, or
in the Catalog, click a polygon map with the right mouse button, and select Vector Operations, Attribute Map from the context-sensitive menu.

The Attribute Map of Polygon Map dialog box appears.

Attribute Map of a Segment Map operation

By creating an attribute map, each segment class name or ID in the original map is replaced by the value, class name or ID found in a certain column in the attribute table.

To create a attribute map of a segment map:

from the Operations menu in the Main window, choose Vector Operations and select Segments, Attribute Map, or
in the Operation-tree, open the Vector Operations, Segments item, and double-click the Attribute Map of Segment Map item, or
in the Operation-list, double-click the Attribute Map of Segment Map item, or
in the Catalog, click a segment map with the right mouse button, and select Vector Operations, Attribute Map from the context-sensitive menu.

The Attribute Map of Segment Map dialog box appears.

Attribute Map of a Point Map operation

By creating an attribute map, each point class name or ID in the original map is replaced by the value, class name or ID found in a certain column in the attribute table.

To create a attribute map of a point map:

from the Operations menu in the Main window, choose Vector Operations and select Points, Attribute Map, or
in the Operation-tree, open the Vector Operations, Points item, and double-click the Attribute Map of Point Map item, or
in the Operation-list, double-click the Attribute Map of Point Map item, or
in the Catalog, click a point map with the right mouse button, and select Vector Operations, Attribute Map from the context-sensitive menu.

The Attribute Map of Point Map dialog box appears.

Attribute Map of a Raster Map operation

By creating an attribute map, each class name or ID of the pixels in the original map is replaced by the value, class name or ID found in a certain column in the attribute table.

To create an attribute map of a raster map:

from the Operations menu in the Main window, choose Raster Operations and select Attribute map, or
in the Operation-tree, open the Raster Operations item, and double-click the Attribute Map of Raster Map item, or
in the Operation-list, double-click the Attribute Map of Raster Map item, or
in the Catalog, click a raster map with the right mouse button, and select Raster Operations, Attribute Map from the context-sensitive menu.

The Attribute Map of Raster Map: dialog box appears.

Tip:

The colors in which an attribute map is displayed, depend on the domain of the specified attribute column:

If you used a domain Value attribute column, you can either select one of the standard value representations or create your own representation by clicking the create button in the Display Options dialog box which appears when you display the attribute map.
If you used a domain Class attribute column and this domain already has a user-defined representation, then this representation is automatically selected in the Display Options dialog box which appears when you display the attribute map. In the Display Options dialog box, you can also select another existing representation or create a new representation by clicking the create button.

For more information, refer to the Display Options dialog boxes.