Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Quantifying urban areas with multi-source data based on percolation
  theory   Quantifying urban areas is crucial for addressing associated urban issues
such as environmental and sustainable problems. Remote sensing data, especially
the nighttime light images, have been widely used to delineate urbanized areas
across the world. Meanwhile, some emerging urban data, such as volunteered
geographical information (e.g., OpenStreetMap) and social sensing data (e.g.,
mobile phone and social media), have also shown great potential in revealing
urban boundaries and dynamics. However, consistent and robust methods to
quantify urban areas from these multi-source data have remained elusive. Here,
we propose a percolation-based method to extract urban areas from these
multi-source urban data. We derive the optimal urban/non-urban threshold by
considering the critical nature of urban systems with the support of the
percolation theory. Furthermore, we apply the method with three open-source
datasets - population, road, and nighttime light - to 28 countries. We show
that the proposed method captures the similar urban characteristics in terms of
urban areas from multi-source data, and Zipf's law holds well in most
countries. The accuracy of the derived urban areas by different datasets has
been validated with the Landsat-based reference data in 10 cities, and the
accuracy can be further improved through data fusion ($\kappa=0.69-0.85$, mean
$\kappa=0.78$). Our study not only provides an efficient method to quantify
urban areas with open-source data, but also deepens the understanding of urban
systems and sheds some light on multi-source data fusion in geographical
fields.

32
The categories of this paper are: atom-ph
35
The categories of this paper are: mtrl-th
17
The categories of this paper are: q-fin
25
The categories of this paper are: patt-sol
9
The categories of this paper are: nlin
6
The categories of this paper are: astro-ph
22
The categories of this paper are: chao-dyn
12
The categories of this paper are: nucl-th
10
The categories of this paper are: q-bio
36
The categories of this paper are: cmp-lg
21
The categories of this paper are: adap-org
23
The categories of this paper are: solv-int
1
The categories of this paper are: cs
13
The categories of this paper are: quant-ph
24
The categories of this paper are: dg-ga
30
The categories of this paper are: q-alg