Open Data and Collaboration

Contributions to the quantitative civil war literature increasingly rely on geo-referenced data and disaggregated research designs. While this is a welcome trend, it necessitates geographic information systems (GIS) skills and imposes new challenges for data collection and analysis. So far, solutions to these challenges differ between studies, hampering replication and extension of earlier work. This article presents a standardized structure for storing, manipulating, and analyzing high-resolution spatial data. PRIO-GRID is a vector grid network with a resolution of 0.5 x 0.5 decimal degrees, covering all terrestrial areas of the world. The released dataset comes with cell-specific information on a large selection of political, economic, demographic, environmental, and conflict variables for all years, 1946–2008. A simple descriptive data assessment is offered to demonstrate how PRIO-GRID may be applied in social science research.

Numerical models, such as hydrodynamic and climate models, produce output with a large number of variables and a large number of grid cells and time steps. Further use of the resulting data products has been challenging, especially for further use outside the institute of origin. Due to the vastness of the data, simply downloading copies of data is impossible. Web services are therefore used to access subsets of the data. The most mature candidates for working with gridded data are OPeNDAP and WCS. Here we compare these two protocols to serve gridded data through the web.

In the framework of the new Dutch National Model and Data Centre (NMDC) a distributed data storage has been realized by coupling OPeNDAP servers (data cloud). A WCS service layer is provided for the same data. This allows us to compare OPeNDAP and WCS. Using several use cases, we compare the data model, terminology, features and usability, both for developers and end-users.

The data models show the different origin of the two standards. The OPeNDAP data model, called the common data model (CDM), is based on the merge of the data models from the NetCDF software, the HDF5 software and the OPeNDAP protocol. It is based around the use of multidimensional arrays. The Coverage data model uses a more abstract terminology, based on geospatial data types.

The terminology that the CDM uses is more closely related to the terminology used in numerical modelling. A grid of air pressure depending on latitude longitudes is called a DiscreteGridPointCoverage in the WCS terminology, while it is represented by the variables latitude, longitude and air_pressure with the attribute coordinates=”lon lat” and grid_mapping in the CDM model with the CF convention.

The Fish Passage Center (FPC) maintains a hatchery database of anadromous salmonid species released from State, Federal, and Tribal hatcheries in the Columbia River Basin. This database is updated routinely throughout the fish passage season. Over the past year, the location of the hatcheries and the release sites were mapped and an online mapping application was developed to allow the users of this database a spatial view of where hatcheries have released anadromous salmonids throughout the Columbia River Basin since 1979. Additionally, it allows users to map and download real-time release data for the current year. Application users spatially query for and select a specific hatchery and all of the locations where the selected salmonid species have been released by that hatchery. The map zooms to the spatial extent of the selected sites and a table containing the release data is opened and the data are made available for download in several formats. There are other spatial queries available in the application including: selecting release sites and data by watershed, major river or by major river zone. The release data provide regional Salmon Managers with the information needed to assess the current year’s migration of juvenile hatchery fish through the hydrosystem. In addition, the release data have been used to access present and historical production releases, timing and magnitude of salmon runs, population estimates and the proportion of hatchery fish that are tagged or clipped. This presentation / poster describes the development of the hatchery mapping application. The open source software stack used for the FPC Hatchery Mapping Application includes: MapServer, PostgreSQL, PostGIS, and p.mapper.