  Scaling of geographic space refers to the fact that for a large geographic
area its small constituents or units are much more common than the large ones.
This paper develops a novel perspective to the scaling of geographic space
using large street networks involving both cities and countryside. Given a
street network of an entire country, we decompose the street network into
individual blocks, each of which forms a minimum ring or cycle such as city
blocks and field blocks. The block sizes demonstrate the scaling property,
i.e., far more small blocks than large ones. Interestingly, we find that the
mean of all the block sizes can easily separate between small and large blocks-
a high percentage (e.g., 90%) of smaller ones and a low percentage (e.g., 10%)
of larger ones. Based on this regularity, termed as the head/tail division
rule, we propose an approach to delineating city boundaries by grouping the
smaller blocks. The extracted city sizes for the three largest European
countries (France, Germany and UK) exhibit power law distributions. We further
define the concept of border number as a topological distance of a block far
from the outmost border to map the center(s) of the country and the city. We
draw an analogy between a country and a city (or geographic space in general)
with a complex organism like the human body or the human brain to further
elaborate on the power of this block perspective in reflecting the structure or
patterns of geographic space.
  Keywords: Power law distribution, scaling of geographic space, data-intensive
geospatial computing, street networks
