Research Of Cartographic Generalization Based On Object Balance

At present,the traditional technology of cartography is relatively mature,there is a complete set of cartographic standards.In the conditions of the traditional single scale,all the various elements will be generalized in accordance with the same selection criteria and norms of the scale,this inevitably would bring the cartographers some limitations and constraints when mapping what maybe cause imbalance and information asymmetry on a map.In this way,the effective information can not be communicated,and the space of a map is wasted.Therefore,this paper presents a thought of cartographic generalization based on object balance to order to keep map balance though adjusting the elements in different density of the region to improve legibility and readability of the map.In this paper,we firstly define the concept of object balance,which is a prerequisite for follow-up.In order to achieve the purpose of balancing the object,we proposed the solution of generalization based on variable scale.When we draw a map,we use variable scale instead of the traditional single scale and generalize the elements in different regions with different selection criteria to achieve the balance.Article discusses three problems of variable scale: how to determine the scale,how to select elements and topological relation between elements.Determining the scale is how to divide areas and use some formula to determine the scale of different regions.Selecting feature is how to use different selection criteria and generalization algorithms on the conditions that the scale has been confirmed to generalize features in different region.In this paper,we discuss relevant algorithm of the three kinds of features(point/polyline/polygon).Topological relation between elements is a problem we must pay attention to,it is related to the correctness of the relationship among the features.The paper will discuss and give some solutions.Through the above research,to some extent the application of variable scale ensure relatively map information balanced and improve readability and legibility of the map.It also makes full use of the space map,not wasting paper.Finally,some examples are given to support this pattern of thinking.At present,the research on this idea is not yet mature,we will continue to improve and supplement the idea.