The EURODEER database is the repositories where data coming from the different partners are standardized, stored and shared to be analyzed. The first goal of the project is to investigate variation in roe deer behavioural ecology along environmental gradients or population responses to specific conditions, such as habitat changes, impact of human activities, different hunting regime. Therefore, the main set of data stored into the EURODEER database are those generated by biotelemetry sensors to monitor animals movement, particularly:
- GPS data
- VHF data
- Activity data (accelerometer)
While these data sets provide a huge mine of data to be mined, it is when they are couple with additional information like that of the individuals, populations, management regimes and the environment that they can help to fully decipher the mechanisms of animals movement. This is why EURODEER is investing a lot in getting these information from each partner, standardize them and integrate into the analysis. This is a complex process but ultimately it is the biggest added value of the collaboration among scientist in addition to the integration in a single repository of the data coming from sensors. The work of data standardization requires long and iterative discussions but it is also an opportunity to identify good practice that can then be shared with a wider scientific community
The quality of the data is of primary importance for the project because inconsistent or erroneous information can lead to misleading scientific interpretations of the animals movement. In additions to the controls and quality checks performed by each research group, all data are validated before they are included into the database. The experience of the project clearly show how, due to the nature (size and complexity) of the data sets, very rarely data provided by each group are without errors. These can be due to a number of possible reasons, for example to wrong information recorded in the field (e.g. start/end of a sensor deployment), errors in data acquisition/transmission by the sensors, mistakes in data handling when it is not properly automated/supervised.
Database data modeling
Data modeling is an important issue when data structure becomes large and complex, as in the case of animal movement tracking, where a large set of sensors, environmental variables and ancillary data sets (e.g. individuals, captures, population, managment regimes, study areas) can potentially interact and be used by many research groups in a collaborative framework. A data model (or database model) is the link between the elements of the real-world (e.g. moving animals, sensors, the environment) and the physical representation of those elements in a database (in EURODEER case, a relational database). It "translates" the researcher's conceptual model into a scheme inside the information system. A special effort towards a conceptual data model capable of accurately describing the real world was needed to develop the EURODEER database. It took into account the complexity of the real world problems to be solved, the nature of the application of the data, the technical environment, the policies governing the use of the information and the expected performance standard of the application. This modeling approach ensure in the long term that the software platform built around GPS data can efficiently manage data. Developing a database without a proper data model is like building a house without an architectural plan.
The software platform
The new tracking technologies represent a powerful tool for wildlife studies, providing the researchers with vast, precise, high frequency animal movement datasets. Additional environmental and socio-economic datasets can be put into relation with animal distribution and space use, therefore allowing to address questions on ecosystem processes. At the same time, however, this information framework poses a number of new challenges in terms of data storage, management, analysis and dissemination. The EURODEER software integrates different software applications into a flexible, modular and interoperable platform with a server-client architecture, where data are stored in a Spatial Relational DataBase Management System (SRDBMS) to which client applications can be concurrently and remotely connected to perform specific tasks. This approach offers effective data handling and management techniques that are essential in maintaining the integrity and accuracy of the movement data and facilitate analysis, querying and reporting. Spatially enabled relational database management systems (also called "spatial database", "Spatial Relational DataBase Management System - SRDBMS", "geodatabase") are database designed to store, query, and manipulate spatial data. The main advantage of SRDBMS, as compared to flat file based data storage, is that they embed GIS capabilities in the RDBMS. This includes support for SQL and the ability to generate complex geospatial queries. While traditional GIS are focused on advanced data analysis and visualization, providing a rich set of spatial operations, on few data, spatial databases allow simple spatial operations which can be efficiently undertaken on a large set of elements . This approach suits perfectly the peculiarities of GPS data.
The use of a RDBMS has several advantages, for example:
- It has a persistent and very large data storage capability.
- It can implement automated procedures to receive, screen, and store data from GPS telemetry devices.
- GPS data can be linked to complex spatial and non-spatial data in a common data structure.
- Multiple users can simultaneously access data with different permissions.
- It has the ability to manage different time and spatial reference systems in the same framework.
- It has fast data search and retrieval capabilities.
- It supports controls on data consistency and reduce errors.
- In the modular structure, many software applications can be connected to the database to perform specific tasks while data are kept into the database, avoiding data replication.
- Specific user-friendly interfaces for data visualization and analysis.
- Flexibility to add new modules and develop new tools.
- Web-based tools to disseminate data and results.
The open source option
The EURODEER software platform is based on open source software. The database is developed on PostgreSQL/PostGIS with R functionalities embedded through Pl/R. This choice is based on several reasons, particularly:
- A wide variety of free and powerful software are available, including RDBMS, SRDBMS, GIS packages and statistical softwares to implement GPS telemetry applications
- Adaptation to personal needs are possible with low entry barrier
- The free software licenses help the diffusion of the system in the scientific community
- Open source GIS software packages commonly use international standards for spatial formats and data exchange protocols ensuring compatibility among different GIS software packages and in heterogeneous work groups
- Open source software tools are free: money can be used to customize the platform and to acquire data
Each researcher can then connect with the database using his/her favourite tool, including proprietary software.