During the process of graph perception, short-term memory and long-term memory were involved. While the capacity of short-term memory was about 4-6 items at one time. Therefore, generalization was applied in mapmaking process to reach the visual communication effects. From the two decades, remote sensed images were employed to show the detail ground truth, they even replace some functions of maps. Under the hypothesis that generalization is required during mapmaking process, three classified images and three generalized maps were selected to compare their visual effect in this research. The results reveal the communicate speed in four colors maps was 10 seconds faster than in the images; in six colors maps was 20 seconds faster than in the images. The visual effect difference was significant between images and maps (p=0.000). Also, the more colors the more effective (p=0.019). Both hypotheses that generalization was required during mapmaking process and gender difference was not significant were approved in this study.