Fundamental Functional Capabilities

ArcGIS is a very big software system with literally thousands of functional capabilities and tens of millions of lines of software code. It is impossible, and in any case worthless, to try to describe each piece of functionality here. Instead, the approach will be to present some of the core foundational concepts and capabilities.

The best way to understand ArcGIS is to start with the core information (some people use the term data) model since it is this which defines what aspects of the world can be represented in the software and is the push-off point for understanding how things can be manipulated. ArcGIS’s core information model is called the geographic database or geodatabase for short. The geodatabase defines the conceptual and physical model for representing geographic objects and relationships within the system. Geodatabases work with maps, models, globes, data, and metadata. Instantiated geodatabases comprise information describing geographic objects and relationships that are stored in files or DBMS. These are bound together at runtime with software component logic that defines and controls the applicable processes. It is this combination of data (form) and software (process) which makes the geodatabase object oriented and so powerful and useful. For example, a geodatabase can represent a linear network such as an electricity or road network. The data for each link and node in a network is stored as a separate record. Functions (tools or operators), such as tracing and editing that work with networks, access all the data together and organize it into a network data structure prior to manipulation. Geodatabases can represent many types of geographic objects and associated rules and relationships including vector features (points, lines, polygons, annotations [map text], and 3D multipatches), rasters, addresses, CAD entities, topologies, terrains, networks, and surveys. In ArcGIS, geographic objects of the same type (primarily the same spatial base – dimensionality, projection, etc.) are conventionally organized into a data structure called a layer. Several layers can be integrated together using functions such as overlay processing, merge, and map algebra. Geodatabases can be physically stored in both file system files and DBMS tables (e.g., in DB2, Oracle, and SQL Server).

It is convenient to discuss the functional capabilities of ArcGIS in three main categories: geovisualization, geoprocessing, and geodata management.

Geovisualization, as the name suggests, is concerned with the visual portrayal of geographic information. It should come as no surprise that many people frequently want to visualize geographic information in map or chart form. Indeed many people’s primary use for a GIS is to create digital and/or paper maps. ArcGIS has literally hundreds of functions for controlling the cartographic appearance of maps. These include specifying the layout of grids, graticules, legends, scale bars, north arrows, titles, etc., the type of symbolization (classification, color, style, etc.) to be used, and also the data content that will appear on the final map. Once authored, maps can be printed or published in softcopy formats such as PDF or served up over the web as live map services. Additionally, many geographic workflows are best carried out using a map-centric interface. For example, editing object geometries, examining the results of spatial queries, and verifying the results of many spatial analysis operations can only really be performed satisfactorily using a map-based interface. ArcGIS supports multiple dynamic geovisualization display options such as 2D geographic (a continuous view of many geodatabase layers), 2D layout (geodatabase layers presented in “paper” space), 3D local scenes (strictly a 2.5D scene graph view of local and regional data), and 3D global (whole-Earth view with continuous scaling of data).

The term “geoprocessing” is used to describe the spatial analysis and modeling capabilities of ArcGIS. ArcGIS adopts a data transformation framework approach to analysis and modeling: data + operator = data. For example, streets data + buffer operator = streets_with_buffers data. ArcGIS has both a framework for organizing geoprocessing and an extensive set of hundreds of operators that can be used to transform data. The framework is used to organize operators (also called functions or tools) and compile and execute geoprocessing tasks or models (collections of tools and data organized as a workflow) and interfaces to the other parts of ArcGIS that deal with geodata management and geovisualization. The set of operators includes tools for “classic” GIS analysis (overlay, proximity, etc.), projection/coordinate transformation, data management and conversion, domain-specific analysis – 3D, surfaces, network, raster, geostatistics, linear referencing, cartography, etc. – and simulation modeling. Geoprocessing is widely used to automate repetitive tasks (e.g., load 50 CAD files into a geodatabase); integrate data (e.g., join major_streets and minor_streets data layers to create a single complete_streets layer), as part of quality assurance workflows (e.g., find all buildings that overlap); and to create process models (e.g., simulate the spread of fire through a forested landscape).

Geodata management is a very important part of GIS not least because geodata is a very valuable and critical component of the most well-established operational GIS. It is especially important in large enterprise GIS implementations because the data volumes tend to be enormous, and multiple users often want to share access. ArcGIS has responded to these challenges by developing advanced technology to store and manage geodata in databases and files. An efficient storage schema and well-tuned spatial and attribute indexing mechanisms support rapid retrieval of data record sets. Coordinating multiuser updates to continuous geographic databases has been a thorny problem for GIS developers for many years. ArcGIS addresses this using an optimistic concurrency strategy based on versioning. The versioning data management software, data schema, and application business logic are a core part of ArcGIS. The data in ArcGIS can be imported/exported in many standard formats (e.g., dxf and mif) and is accessible via standard-based interfaces (e.g., OGC WMS and WFS) and open APIs (application programming interfaces, e.g., SQL,. Net, and Java), and the key data structure formats are openly published (e.g., shapefile and geodatabase).

Fundamental Design Philosophy

The ArcGIS software has evolved considerably over the two and a half decades of its existence as the underlying computer technologies, and concepts and methods of GIS have advanced. Nevertheless, many of original design philosophies are still cornerstones of each new release. Not surprisingly, the original design goals have been supplemented by more recent additions which today drive the software development process. This section discusses the fundamental design philosophies of ArcGIS in no particular order of significance.

Commercial off-the-shelf (COTS) hardware. ArcGIS has always run on industry standard COTS hardware platforms (including computers and associated peripherals, such as digitizers, scanners, and printers). Today, hardware is insulated by a layer of operating system software (Windows, Linux, Solaris, etc.), and this constitutes much of the underlying “computing platform” on which the GIS software runs. The operating system affords a degree of hardware neutrality. ArcGIS runs on well-established mainstream operating systems and hardware platforms.

Multiple computer architectures. Parts of the ArcGIS software system can run on desktop, server, and mobile hardware. There is also a portion of ArcGIS that is available online for use over the web. The software can be configured to run stand alone on desktop and mobile machines. It can also be configured for workgroup and enterprise use so that it runs as a client-server and/or distributed server-based implementation. This offers considerable flexibility for end-use deployment. The newest release of the software is adept at exploiting the web as a platform for distributed solutions.

GIS professionals. The target user for the core of ArcGIS is the GIS professional (loosely defined as a career GIS staff person). GIS professionals often build and deploy professional GIS applications for end users (e.g., planners, utility engineers, military intelligence analysts, and marketing staff). The software is also frequently incorporated in enterprise IT systems by IT professionals and is increasingly being used by consumers (members of the general public with very limited GIS skills).

Generic toolbox with customization. From the outset ArcGIS was designed as a toolbox of generic GIS tools. This means that functional GIS capabilities are engineered as self-contained software components or tools that can be applied to many different data sets and application workflows. This makes the software very flexible and easily adaptable to many problem domains. The downside to this is that the tools need to be combined into application solutions that solve problems, and this adds a degree of complexity. In recent releases of the software, this issue has been ameliorated by the development of menu-driven applications for key geographic workflows (editing, map production, 3D visualization, business analysis, utility asset management and design, etc.).

Strong release control. ArcGIS is a software product which means that it has well-defined capabilities, extensive online help and printed documentation, and add-on materials (third-party scripts, application plug-ins, etc.), a license agreement that controls usage, and that it is released under carefully managed version control. This means that additions and updates to the product are added only at a new release (about two to three times a year).

Internationalized and localized. The core software is developed in English and is internationalized so that it can be localized into multiple locales (local languages, data types, documentation, data, etc.). The latest release of ArcGIS has been localized into more than 25 local languages including Farsi, French, German, Hebrew, Japanese, Italian, Mandarin, Spanish, and Thai.

Business

Businesses use many types of information – geographic locations, addresses, service boundaries, sales territories, delivery routes, and more that can be viewed and analyzed in map form. ArcGIS software integrated with business, demographic, geographic, and customer data produces applications that can be shared across an entire organization. Typical applications include selecting the best sites, profiling customers, analyzing market areas, updating and managing assets in real time, and providing location-based services (LBSs) to users. These applications are used extensively in banking and financial services, retailing, insurance, media and press, and real estate sectors.

Education

In the education sector, ArcGIS is applied daily in administration, research, and teaching at the primary, secondary, and tertiary levels. In recent years, ArcGIS use has grown tremendously, becoming one of the hottest new research and education tools. At the primary and secondary level, GIS provides a set life skills and a stimulating learning environment. More than 100 higher education academic disciplines have discovered the power of spatial analysis with GIS. Researchers are using GIS to find patterns in drug arrests, study forest rehabilitation, improve crop production, define urban empowerment zones, facilitate historic preservation, develop plans to control toxic waste spills, and much more. GIS is also a useful tool for the business of education. It is used to manage large campuses, plan campus expansion, and provide emergency campus response plans. It is also used by administrators to track graduates and alumni or identify from where potential new students may be recruited.

Government

Government organizations throughout the world are under increasing pressure to improve services and streamline business practices while adhering to complex political or regulatory requirements. To do so, they must digest huge amounts of information, most of which is tied to a very specific geographic location – a street, an address, a park, and a piece of land. As a result, ArcGIS has become indispensable for most large and many small governments. The applications of ArcGIS are very diverse and their implementation extremely extensive. Very many major government organizations at the national, state, regional, and local levels use ArcGIS. Some of the main application areas include economic development, elections, national policy formulation, homeland security, land records and cadastral solutions, law enforcement, public safety, public works, state and local, sustainable development, and urban and regional planning.

Military

Although ArcGIS is deployed as a niche tool in some application domains, there is increasing realization that enterprise ArcGIS implementations are providing defense-wide infrastructures, capable of supporting fighting missions, command and control, installation management, and strategic intelligence. GIS plays a critical role within the defense community in the application areas of command and control (C2), defense mapping organizations, base operations and facility management, force protection and security, environmental security and resource management, health and hygiene intelligence, surveillance and reconnaissance systems, logistics, military engineering, mine clearance and mapping, mission planning, peacekeeping operations, modeling and simulation, training, terrain analysis, visualization, and chemical, biological, radiological, nuclear, and high explosive (CBRNE) incident planning and response.

Natural Resources

Just as ArcGIS is routinely used in managing the built environment, it is also very popular in measuring, mapping, monitoring, and managing the natural environment. Again the application areas are very wide ranging extending from agriculture to archaeology, environmental management, forestry, marine and coast, mining and earth science, petroleum, and water resources. ArcGIS provides a strong set of tools for describing, analyzing, and modeling natural system processes and functions. Interactions and relationships among diverse system components can be explored and visualized using the powerful analytical and visualization tools that GIS software provides.

Utilities

Utilities (electric, gas, pipeline, telco, and water/wastewater) were among the first users of GIS. Today ArcGIS is involved in many of the core activities of utilities including asset information, business for utilities, network design, emergency management, electricity generation and transmission, land management, outage management, pipeline management, and work force productivity. ArcGIS is used to manage the flow of water and wastewater to service homes and businesses, to track the location and condition of water mains, valves, hydrants, meters, storage facilities, sewer mains, and manholes. The same systems make keeping up with regulatory compliance, TV inspection data, and condition ratings easier. Competitive pressure and regulatory constraints are placing increasing demands on pipeline operators to operate in an efficient and responsible manner. Responding to these demands requires accessibility to information regarding geographically distributed assets and operations. ArcGIS is enabling telecommunication professionals to integrate location-based data into analysis and management processes in network planning and operations, marketing and sales, customer care, data management, and many other planning and problem-solving tasks.