  Spatial organisation of physical form of an urban system, or city, both
manifests and influences the way its social form functions. Mathematical
quantification of the spatial pattern of a city is, therefore, important for
understanding various aspects of the system. In this work, a framework to
characterise the spatial pattern of urban locations based on the idea of
entropy maximisation is proposed. Three spatial length scales in the system
with discerning interpretations in terms of the spatial arrangement of the
locations are calculated. Using these length scales, two quantities are
introduced to quantify the system's spatial pattern, namely mass decoherence
and space decoherence, whose combination enables the comparison of different
cities in the world. The comparison reveals different types of urban morphology
that could be attributed to the cities' geographical background and development
status.
