# Sensor Observation Service API for Providing Gridded Climate Data to Agricultural Applications
## 5 Result and Discussion  
In this research, a grid climatological data source, AmGSD, is wrapped and exposed through a standard web service, SOS API. Connecting AmGSD to SOS API can expand the usability of AmGSD, while agricultural applications have more options to receive point-based climatological data throughout Japan from 1980 to the present. Supported by a Japanese national agricultural project, we are developing an application that visualizes the impact of weather variabilities on cropping yield at the farm scale by utilizing AmGSD data through our SOS API. It retrieves 30 years of climatological data to generate hundreds of weather scenarios that visualize the variability of possible future weather. Then, the scenarios are inputted to a crop model for simulating cropping yield, as well as generating a distribution of expected yields that indicates the impact of the weather variability on the yield. SOS API demonstrates the ability to simplify data retrieval as the complicated heterogeneous data source and the data format are hidden behind the SOS API. As a result, agriculture applications can \begin{table}
\begin{tabular}{l c c c c c c} \hline \hline
**Testing** & **Single-Process** & **Single-Process** & **Multi-Process with** & **Multi-Process** & **Multithread with** & **Multithread** \\
**Scenario** & **with Caching** & **without Caching** & **Caching** & **without Caching** & **Caching** & **without Caching** \\ \hline
1-year with & 0.608 & 1.103 & 0.795 & 1.185 & 1.078 & 1.264 \\
1-year with & 0.708 & 23.413 & 0.800 & 1.370 & 0.813 & 13.913 \\
4-elements & 1.018 & 35.513 & 0.863 & 3.575 & 0.744 & 21.171 \\
30-year with & 4-elements & 1.534 & 676.195 & 1.168 & 91.882 & 1.162 & 639.457 \\ \hline \hline \end{tabular}
\end{table} 
Table 9: Result of the performance test. easily query data through SOS API and obtain point-based time series data by issuing getObservation. Developers do not need to spend time on learning a proprietary structure of a data source and a data format one by one. The benefit of retrieving data through SOS API provides the same data accessing mechanism no matter whether it is a gridded climate data source or a point-based data source. In this regard, the data fusion of a gridded climate and a point-based weather data source can be easily implemented in agricultural applications. Data availability in terms of coverage and temporal scale will be broader. This means that agricultural applications will have more data sources to utilize. SOS API compliance with the international standard ensures interoperability between gridded climate data and point-based data. Our mechanism contributes to the agricultural society by providing a standard API for obtaining climate data, introducing a mechanism that can be applied to meteorological sources to improve data-providing services and make the development of agricultural applications much more convenient. The coverage of the data source in this research is only in Japan; however, similar mechanisms can be applied to a global-scale gridded climate data source. Accordingly, SOS API is the international standard and globally used in various sectors, not only in agriculture, but also in environmental monitoring, such as terrestrial environmental observatories [31] and disaster warning systems, such as the Sensor-based Landslide Early Warning System (SLEWS) [32]. One of the further developments is implementing SOS API authentication based on a user key rather than an IP restriction, so that SOS API can be an easier interface to other data sources based on each data source's accessing policy. User access history can be recorded, which can be used for analyzing the user of interest. On the top of SOS API, we are implementing automatic wiring data sources with SOS API for weather generator models, then SOS API can be used to invoke the model and retrieve simulated future data based on historical data.