Abstract: Outline is very important to the cognition of objects and it is the key attribute to decide the category of objects. For the metaphor map whose purpose is to use the virtual map to express non-spatial data, its outline has operational advantages. This advantage can be exploited to enhance map similarity and promote the establishment of a connection with the real map. At present, the study of metaphor maps emphasizes too much on the map making technology, and pays less attention to map cognitive design. Poor control of the mapping process leads to a strong randomness of the map's outline and to filter the map outlines. We also apply the optimization algorithm to control the filter flow to obtain a satisfactory map outline and to filter the map outlines. The experiments under real data show that this method can obtain a map outline similar to target outline and the outline framework helps to carry out the work of map design and representation.