Brazilians say that the digital census has several advantages over paper and pen methods. They say that the data is more accurate since GPS data will pinpoint the exact location of a household. The GPS data is cross-referenced with satellite images to ensure that responses are correctly geo-tagged. The digital approach allows changes to areas, streets and buildings to be incorporated. This is particularly pertinent in the slums as these areas tend to change quickly and their density mean that printed maps are quickly out of date. The use of digital technology means that mapping is considerably more accurate and that adjustments and changes can be made all the time to ensure that the coverage is as comprehensive as possible.