Unlike ordinary paper maps, different topic data in GIS-rivers, roads, administrative districts, land use, ethnic distributions and so forth-are stored as different layers so the user can exclude any data desired, selecting only the topic he wishes to display, or layer together several topic maps.
與傳統紙地圖不同，GIS 中的不同主題資訊，如河流、道路、行政區劃、土地利用型態、族群住居分佈等等，皆是分層儲存，使用者可以隨意排除其他資訊，只挑選所需主題單獨呈現，或是將幾張主題地圖套疊起來呈現。