  Model web services provide an approach for implementing and facilitating the
sharing of geographic models. The description and acquisition of inputs and
outputs (IO) of geographic models is a key issue in constructing and using
model web services. These approaches for describing and acquiring the data
formats of the IO of geographic models can be classified into two categories,
i.e., intermediate-data-format-based and native-data-format-based. Nonetheless,
these two categories mainly consider the description of the IO of geographical
models but relatively pay little attention to the acquisition. To address this
issue, this paper proposes an approach for automatically parsing data formats
of the IO utilizing the relationship between the IO and source codes. This
proposed approach can utilize such a strict and coupling relationship and the
expression form of the data formats in the source codes to retrospectively
derive the IO data format and automatically generate data format documentation.
The feasibility of the proposed approach has been verified via a geographical
model coded in the FORTRAN language, which shows that it significantly improves
the efficiency of writing data format specifications and promotes sharing
geographic models as model web services.
