Parent Topic: IWORKS

Set Georeferenced Map Area

The Set Georeferenced Map Area panel allows the user to either set or edit the georeferencing information of an image. This panel also permits the user to specify the area to which an image will be loaded in the ImageWorks window.

The Set Georeferenced Map Area panel can be invoked by selecting View|Set Map Area (select the "Set Map Area" option from the "View" pull-down menu) in ImageWorks.

The top area of the panel contains georeferencing information. There is an option menu to select different coordinate systems, and there are fields to display (or edit) the UTM Zone, the upper left corner coordinates, and the lower right corner coordinates. This is known as a ``GeoEdit'' control.

The next section of the panel contains two radio boxes for selection of the "Informational Only" or "User Controlled" mode. The "Informational Only" mode displays the georeferencing values of the image that is initially loaded into ImageWorks.

The "User Controlled" mode permits the user to specify the area represented by the ImageWorks work area. Note that this is the entire work area in memory, not necessarily just what is shown in the view window.

When an image is loaded with the "User Controlled" mode selected, the portion of the image, and the area of the display it is loaded to will be adjusted according to the georeferenced bounds established in this panel.

NOTE: For UTM coordinate systems, it is important to specify the UTM ZONE if the image that will be loaded contains UTM Zone information.

The following example shows how the Set Georeferenced Map Area panel can be used:

Start ImageWorks.

Load the demonstration database file called "irvine.pix".

Launch the "Set Georeferenced Map Area" panel.

In the "Informational Only" mode, the panel displays the georeferencing information of "irvine.pix". NOTE: The image is in UTM coordinates and has a Zone number.

In the "User Controlled" mode, the user can choose to edit the georeferencing information of the database file.

Toggling back and forth between the "Informational Only" and "User Controlled" mode will clear any edited georeferenced values to their corresponding default values.

To set a georeferenced map area for an image that will be loaded into ImageWorks, make sure that the "User Controlled" mode is selected. If required, enter a UTM Zone value similar to that of the image that will be loaded. Then load the demonstration file called "eltoro.pix". The image from "eltoro.pix" will align within the specified georeferenced values.

NOTE: Once two or more images of different coordinate systems are loaded and assigned to a specified georeferenced area, switching to the "Informational Only" mode would not display any relevant georeferencing information.

The georeferencing information of each image can be viewed by selecting View|Image Info (select "Image Info" from the "View" pull-down menu).