In Kontokosta’s passage, the author mentioned the “slice of the city”. It could be considered a kind of model of city, or similar to the “one to one map” in the previous readings. They are both the model of a city, but in the readings, one is important and profitable to smart city, another one is not. The difference between them is the scale of data which was collected. So, What scale of data is a good volume for developing of smart city? How to determine the scale or the volume?