Your GIS database is an abstraction of reality—a model of the real world that needs to serve its intended purpose while still being of a manageable size. So how do you build your database to insure it fully supports the needs of your organization without burdening the system with superfluous information? With a well-designed data model.
A GIS data model describes the thematic layers used in the application (for example, building locations, roads, and political boundaries); their spatial representation (for example, point, line, or polygon); their attributes; their integrity rules and relationships (for example, in the U.S., counties must nest within states); their cartographic portrayal; and their metadata requirements. A good GIS data model needs to do all of these things while maintaining the difficult balance between the compromises of abstraction and the heavy burden of completeness.
To support our user community, ESRI has established a set of best practices geodatabase designs for various industry and application domains. These database design models are intended to help GIS users rapidly become productive with the geodatabase and to share what really works among users and our developer communities. ESRI strives to build essential data models; not comprehensive models, but generalized templates focused on common data elements that can benefit a wide variety of users in an industry or application area. Because data models are designed in close partnership with our user community, the resulting models are based on real business needs and are tested and refined in real-world workflows.
The content of the data models available for free download from ESRI can vary, but can include:
- A case study implementation that includes a small sample database.
- A geodatabase template for importing the data model as a template on which to base a system.
- A white paper explaining the design.
- A data model poster.
- Tips and tricks on how to utilize the data model from the case study and how to use it in your work.
Some of the ArcGIS data models also have important community-based Web links for particular domains to allow collaboration in developing designs and concepts.
ESRI ensures that ArcGIS data models implement relevant standards as they evolve. For example, the land records and the ArcHydro data models are based on proven standards over the past decade. ESRI also monitors and participates in many standards-based efforts at ISO, OGC, FGDC, Geospatial One-Stop, and ANSI. All appropriate standards are incorporated into data models.
Each ArcGIS data model uses commonly adopted spatial representations (e.g., points, lines, and polygons), classifications, and map layer specifications that can be implemented in any GIS. Each data model specifies the commonly used integrity rules for key data layers and feature classes. ArcGIS data models can be widely adopted regardless of the system architecture.
Academic and industry leaders collaborate with ESRI to create and design data model templates that can be used with ArcGIS. ESRI’s vision is to build many industry-specific data models in order to simplify the process of implementing projects, and to promote and support standards that exist in our user communities.
ArcGIS data models available today for free download include Address, Agriculture, Atmospheric, Basemap, Biodiversity, Building Interior Space, Carbon Footprint, Census-Administrative Boundaries, Defense-Intel, Energy Utilities, Environmental Regulated Facilities, Fire Service, Forestry , Geology , GIS for the Nation, Groundwater, Health, Historic Preservation and Archaeology, Homeland Security, Hydrology, Land Parcels, Local Government, Marine National Cadastre, Petroleum, Pipeline, Raster, Telecommunications, Transportation, Water Utilities, and more.
For more information or to get started with one of these data models today, please visit the on the Downloads for Data Models page ESRI Support Center. You can read about the goals and process in the Introduction to ArcGIS Data Models, and visit the Data Model tips and tricks page to learn common methods and best practices. You can also visit the ESRI data model discussion forum to share your ideas, thoughts, and questions with other users.