Legend is information about symbols (colour, shape, line type, etc.) in the map. It helps reader to understand the map. In LCM, it also helps the system to compare two images. The picture below shows the error message in LCM IDRISI taiga when adding road image. There is no legend in the basis roads layer. How to add a legend to our map?

Even we use IDRISI selva that having a “harmonize” function to guide users to match the images, basis roads layer must be edited with a legend in selva as well as taiga version. Understanding how to match two images manually is very useful for the user. Click the image to be edited, e.g. road image, to add a legend.

In “metadata” click the Categories to fill the legend. Fill the category and code that similar to other images. Chose “copy from” for faster filling without typing the code and category. After filling the categories, when we open this image, the legend is showed beside (upper right) the map.

This is simple yet very useful.