| iTool User's Guide: Working with Maps |

## Displaying an Image

You can visualize image data in the iMap tool as you would in the iImage tool. To learn more about visualizing image data, see Displaying Images.

Note By default, the iMap tool creates an image visualization if given a 2D array or a Truecolor image. This image is warped internally to fit the map projection, if one is present. The actual image data itself remains unchanged.

When you open an image in the iMap tool, you need to register the image to define how the pixel data corresponds to points on the earth's surface. For more information on this process, see Registering an Image.

Once you have image data in the iMap tool, all of the features of the iImage tool are available. For more information, see Working with Images.

You can export the mapped image by selecting File Export. When the IDL Data Export wizard opens, choose the "To a file" option, the image visualization to save, and the output file format. The result will be the image warped to the current map projection.

Note Depending on the map projection, the alpha channel might be used to mask out pixels outside the map boundary. In this case, you can export the image to a file format that supports four channels, such as TIFF, PNG, or JPEG2000.

IDL Online Help (March 01, 2006)