What is a Geodatabase? Importance of a Geodatabase?
What is a Geodatabase? Importance of a Geodatabase?
What is Geodatabase?
A geodatabase is a collection of data that is organized to facilitate the sharing and use of geographic information.
A geodatabase can be used to store information about natural or man-made features on the Earth’s surface, including addresses, road networks, and park boundaries.
A geodatabase is a type of relational database that stores geographic information.
It is a container for storing spatial and attribute data, as well as the relationships that exist between them.
Using rules, relationships, and topological associations, features and their associated attributes in a geodatabase, a vector data format, can be structured to work together as an integrated system.
In other words, the geodatabase enables you to model the real world as simply or as complexly as your requirements require.
Geodatabases are created, edited, and managed in ArcCatalog and ArcMap using the standard menus and tools.
History of Geodatabase
Geodatabase databases hold information about features and the topological relationships between features that make up a geographic or spatial data model.
These databases are built upon the foundation of relational database management systems (RDBMS).
It is this RDBMS model that provides today’s geodatabases with the wide range of capabilities to efficiently manage complex, changing, and large datasets. This same RDBMS model also inspired earlier database models that were used to store geographic information.
The world’s first attempt at storing geographic information occurred in the mid-1800s. A geographic database was developed to manage the information collected from the U.S. Coast Survey (a unit of the U.S. Treasury Department).
The project was called the Coast and Geodetic Survey, and its primary purpose was to use triangulation methods to accurately map and measure coastlines, harbors, and rivers throughout the nation.
In the early 1980s, the U.S. military used its Remote Sensing Station Modeling Environment (RSSME) project to create a geodatabase to manage remote sensing data and create a relational topological model of its battlefield.
By the end of the decade, this same geodatabase was extended further so that other agencies could share its data over a network. In other words, the geodatabase became the foundation of a new concept in storage and data management—a fault-tolerant, collaborative distributed environment.
With the explosion of geographic information systems (GIS) and the introduction of machines that are increasingly able to process spatial data, it’s clear that there is a need for geodatabase management tools with user-friendly interfaces and powerful tools.
Types of Geodatabases
Personal Geodatabase
Personal geodatabases are used for storing and managing personal data, such as personal contacts, family trees, and other types of information.
Enterprise Geodatabase
Are also known as ArcSDE® geodatabases).
Enterprise geodatabases are more powerful than personal geodatabases and are used to manage large collections of spatial data such as those found in cities.
Enterprise geodatabases include: ArcGIS Enterprise–The enterprise version of ArcGIS is geared specifically toward government clients.
It offers advanced spatial and image analysis capabilities. ArcGIS Server–This version of ArcGIS is used to manage the geoprocessing created by the enterprise users and to deliver their data to end users.
ArcGIS Desktop–This version of ArcGIS is usable by individuals in addition to government clients.
Geodatabase Design Steps
The steps are:
- Identify the feature types to be stored: point, polygon, line, and area features.
- Determine how each of these feature types will be used to organize your data in terms of:
- Attributes (properties or characteristics) specific to each feature type (e.g. name of a street, city population)
- Relationships between different types of features (e.g., all cities are within a state or congressional districts are polygons within states)
- Organize your spatial data into a rectangular grid by assigning geographic coordinates to each part of the grid:
- x and y coordinates – used for point features (longitude, latitude)
- x, y, and z coordinates – used for attributes (elevation)
- x, y, and a third coordinate – used for 3D geodata (height above sea level)
- Organize your attribute data into columns and rows.
- Organize your data within tables, sets, and subsets.
- Identify the rules, or physical relationships (i.e., topological relations), for each feature type.
- Determine if relationships are one-to-many, many-to-one or one-to-one.
- Create a design that is flexible enough to accommodate future changes and additions to your data.
- Test the integrity of your design using validation tools.
- Create the geodatabase.
Geodatabase geospatial relationship data structures
In a geodatabase, the most prevalent forms of geographic relationship data structures are:
Topology
This is the transversal data structure that defines how a feature is associated with another. The topology can store relationships across any number of levels, such as:
- Direct-to-feature connections
- Part-to-part connections
- Feature to subset or sub country
- Subset to region
- Some of these are static and some are dynamic or temporal (e.g., a static parent-child relationship can be changed to a dynamic one).
Topology is created using the 3D Analyst extension of ArcGIS.
Geometric Network
A set of linked edges and junctions (line and point characteristics) that are used to describe and mimic the behavior of a common network architecture in the actual world, together with connection rules.
Water distribution, electricity lines, gas pipelines, telephone services, and stream water flow are all resource flows that may be modeled and studied using a geometric network.
Network Dataset
A network dataset is a collection of linked edges and junctions, as well as turn attributes and connectivity rules, that depict and simulate the behavior of transportation network systems. Undirected network flows that may be represented using a network dataset include city highways, roads, and streets, as well as rail lines and bus routes.
Terrain
A data structure created from a large number of elevation measurement points, often derived from remote-sensing data sources.
It is a data format based on triangulated irregular networks (TIN) with many degrees of resolution that is used to depict surface morphology. A terrain is a type of surface model that is used in 3D surface modeling applications.
Cadastral Fabric
A continuous surface of connected parcel characteristics that displays a land’s survey record.
This data format facilitates the integration of GIS data with survey data in order to maintain a consistent and accurate survey record.
Importance of Geodatabase in GIS
Cities and other large geographic regions have been the primary target of GIS.
In a geographic information system, a geodatabase is an essential tool for storing, manipulating, and displaying spatial data. It is used for the management of spatial data to support a number of important tasks including:
- Geodatabase enables the creation of intelligent maps that accurately reflect complex relationships between locations and attributes such as shape, size, elevation, and position.
- Geodatabase increases the accuracy of spatially referenced data.
- Geodatabase improves the quality of spatial analysis and offers users additional ways to view and analyze data.
- Geodatabase provides faster and easier access to spatial data.
Difference between database and Geodatabase
Geodatabase or spatial database is a technology used to store and manage spatial data, whereas a database is a technology that supports the management of data.
A geodatabase encompasses the features of a database, but also includes additional features such as support for coordinate reference systems and coordinate transformation.
Geodatabase is a collection of spatial databases. A geodatabase is the parent and the spatial database is the child, where each geodatabase can contain one or more spatial databases, and each spatial database can be associated with only one geodatabase.
Geodatabases reside on a file system, while spatial databases reside on a computer’s memory.
A geodatabase or spatial database is used to store and manage vector data as well as raster data. The database can be used to store, retrieve, manage and edit both vector and raster data. Some database management systems do not provide support for both types of data, while others do.
Geodatabase or spatial database is a collection of objects that has the following characteristics:
It also contains the following three types of objects:
- Data definition objects – these are used to describe how the other geodatabase or spatial database objects are stored (in terms of their definition).
- Datastore objects – these are used to store the actual data.
- Spatial reference system objects – these are used to hold the information describing what coordinate system is used (the spatial reference system).
Examples of geodatabase applications
- The Military Geographic Reference System is an example of a geodatabase that stores geographic information on military installations and targets, across all branches of the armed forces in the United States and its territories.
The system, known as the Military Geographic Reference System, is the authoritative source for all geographic information pertaining to military assets and their locations. The main objective of this system is to serve as a repository for military geographic data.
- The Federal Emergency Management Agency’s Geodatabase (FEMA) provides a flexible and user-friendly method of storing geospatial information about building, structures and land use.
This information includes location description as well as other geographic data attributes such as elevation and length. The database contains a geographic reference system which allows you to store various geographic data components in a structured manner along with spatial objects.
The system is currently used by the federal government and several state agencies as well as by the private sector.
- The Trademark Data Base (TDB) interacts with the U.S. Patent and Trademark Office that stores trademark data that is vital to the economic and legal health of most American industries.
The TDB supports all trademark owners by providing tools to help in the management of their trademarks. The system creates a geodatabase which contains information pertaining to thousands of trademarks and other information.
- The U.S. Department of Homeland Security Geodatabase (US-DHS) is an authoritative repository for data collected for the purpose of facilitating border enforcement, building secure boundaries, preventing terrorism and administering homeland security grants to state and local governments.
- The USGS Geodatabase (USGS) is a comprehensive national-scale repository of geographic data that includes virtually all geospatial information collected by the U.S. Geological Survey (USGS).
It contains over 2.5 billion points and is the largest single repository for Earth science data in the United States, spanning more than 200 years of collection.
- The Wyoming Geological Survey Geodatabase (WyGEO) is a database of measurements and profiles of terrain in the state of Wyoming. The database is managed by the Wyoming Geological Survey Geodatabase Management Office, a unit within the Econometric Center.
It contains thousands of points with an accuracy to about two inches and employs an encoding for geographic coordinates called North American Datum 1983 that has been adopted by the U.S. Department of Agriculture and several state agencies.
- The USGS National Streamflow Data System Geodatabase (NSSD) stores and manages streamflow data for the United States. NSSD is a comprehensive national-scale geodatabase of streamflow monitoring data from 7,500 to 8,500 streams.
- The USGS National Water-Quality Assessment Database (NAQAD) Geodatabase contains the most comprehensive and detailed water quality information available in the United States. NAQAD is an authoritative repository for water quality information on streams, lakes, and groundwater.
- The USGS National Hydro-Ecological Assessment Geodatabase (NAHED) is an authoritative repository of hydrologic and ecological information related to surface water bodies. NAHED contains geodatabase information that has been collected through a national program administered by the U.S. Geological Survey (USGS).
FAQs
What is the difference between a geodatabase and a spatial database?
Geodatabase is parent and spatial database is child, where each geodatabase can have one or more spatial databases, while each spatial database can be associated with only one geodatabase.
What is geodatabase in GIS?
A geodatabase is a file that stores geographic information, GIS vector and raster data.
What is geodatabase creation?
Geodatabase creation is the process of creating a geodatabase from scratch in ArcGIS. The data is then stored in the geodatabase.
What is a Geodatabase?
A Geodatabase is defined as an object-oriented system that allows storage, retrieval, and display of tabular data with one or more layers on a geographic coordinate system.
GeoBase is an open-source application for managing spatial databases, developed in Java and released under the GNU General Public License (GPL).
What are the types of geodatabases?
A geodatabase is defined as an object-oriented system that allows storage, retrieval, and display of tabular data with one or more layers on a geographic coordinate system.
The geodatabase stores the geographic data in the form of tables which can be opened with a GUI.
What is the difference between geodatabase and raster database?
Raster databases hold images, sometimes called rasters, that are in a grid with cells at regular intervals.
Geometric data storage is what the geodatabase does. Geometric data is stored as vectors or points, with distance each point has from other points taken into account.
What is a spatial database?
A spatial database is a non-tabular geodatabase, which stores the data in the form of raster and/or vector data.
What are the advantages of using a geodatabase over an existing RDBMS?
The advantages of using a geodatabase over existing RDBMS is that it is an object-oriented system. This means you can create more tables, query more information, and more easily manage your databases and data than you can with existing relational databases.
Advanced features of a geodatabase allow you to interact with your data in several different ways. For example, you can create a variety of maps and make them available to users on the Internet without having extensive programming knowledge.
What are the disadvantages of using a geodatabase over an existing RDBMS?
The disadvantage of using a geodatabase over an existing RDBMS is that it’s not as fast as relational database systems. In terms of speed, there are cases where you will not be able to get the speed and performance you want.
The geodatabase is also more difficult to learn than it is to learn an RDBMS. People who have used an RDBMS, they may find the geodatabase too restricting or too complex.
What are some applications of a geodatabase?
Some applications of a geodatabase include creating maps and mapping features, storing information about earthquakes, hurricane paths, and much more.
How does a geodatabase differ from a relational database?
A Relational database is an RDBMS that has an explicit concept of tables and columns. Tables in these databases contain rows and columns. Each row contains a set of related data with each column holding a specific type of data.
How do you create a geodatabase?
To create a geodatabase, you need to have ArcGIS Desktop v9. Also, you need to have the necessary data and other supporting files to create the geodatabase.
GeoBase is an open-source application for managing spatial databases, developed in Java and released under the GNU General Public License (GPL).
What are the types of geodatabases?
Personal geodatabases—All datasets are saved in a Microsoft Access data file that is restricted to 2 GB in size.
Enterprise geodatabases—Also known as multiuser geodatabases, they can be of any size and have an infinite number of users.
Do you have to create your own geodatabase?
No, most of the major GIS systems support geodatabases. The ArcGIS software supports those GIS applications that use the Open Geospatial Consortium’s (OGC) Standards for the Exchange of Spatial Data (ST_PROJ).
What is a multiuser geodatabase?
A multiuser geodatabase is defined as a geodatabase that has a system of individual tables and fields, where each table and field can have multiple users. A user can create tables and fields, whereas the GIS system’s database manager can create new users.
How many features do you need to store in a geodatabase?
The number of features you need to store in a geodatabase depends on the application’s requirements. For example, if your application requires all data to be stored on a particular map, then you should store all the data of that map in a geodatabase.
If your application wants to find the distance from one point to another point, you will require many features.
What is GIS?
GIS stands for geographic information system. GIS combines different types of data about a subset of the earth’s surface for analysis and visualization.
What are geodatabases in ArcGIS?
Enterprise geodatabases, also known as multiuser geodatabases, may be almost limitless in terms of capacity and number of users (The limits differ depending on the DBMS vendor). They are kept in a relational database like Oracle, Microsoft SQL Server, IBM DB2, PostgreSQL, or SAP HANA.
