Symbology

From Wiki.GIS.com

Symbology is defined in geographic information systems (GIS) as the set of conventions, rules, or encoding systems that define how geographic information is represented with symbols on a map. A characteristic of a map feature may influence the size, color, and shape of the symbol used.^[1]

Generically, a symbol is something such as an object, picture, written word, sound, or particular mark that represents something else by association, resemblance, or convention. For example, a red octagon may be a symbol for STOP. On maps, crossed sabres may indicate a battlefield. Numerals are symbols for numbers (amounts). All language consists of symbols. Personal names are symbols representing individuals.^[2]

Maps typically include symbols that represent such features as streets, buildings, streams, and vegetation. Features are shown as points, lines, or areas, depending on their size and extent. Many features are shown by lines that may be straight, curved, solid, dashed, dotted, or in any combination. The colors of the lines usually indicate similar classes of information: topographic contours; lakes, streams, irrigation ditches, and other hydrographic features; land grids and important roads; and other roads and trails, railroads, boundaries, and other cultural features.^[3]

The use of symbology is fundamental to mapping, cartography, and GIS. Symbology comes in many different forms on maps. Graduated colors, Graduated symbols, Dot Density, Proportional Symbols, bar and pie charts, and custom symbols are all types of symbology that are common elements in maps.

We use symbology in maps to portray the geographic world in a map, while at the same time giving the reader of that map the information that the reader is looking for. A legend is a good source of map symbology explanation. In a legend, the meanings of the different symbols, colors, lines, etc. are explained in symbol and text allowing the reader to associate the proper symbol with the intended meaning for the map.

Chart Symbology

Color Ramp

Proportional Symbols

Contents 1 Military symbology 2 Emergency Mapping Symbology 3 References 4 Further Reading

[edit] Military symbology

Military symbology is a system of symbols for use in military cartography for the identification of units, equipment, installations, operations and battle dimensions. An example is APP-6A, the NATO standard for military map-making symbols.

[edit] Emergency Mapping Symbology

Emergency Mapping Symbology are specialized sets of symbols used by various organizations when planning for or responding to emergencies. These emergencies can be naturally caused (tsunami, earthquake, tornado, etc.) or human caused (rioting, terrorism, hijacking, etc.). Currently there is no international standard for emergency mapping symbology which has meant that various nations have created their own national symbology set. Recognized and standardized symbol sets help create a Common Operating Picture (COP) for varied organizations that have been brought together during a crisis or emergency. Symbols that are easy to identify with and easy to distribute are seen as key elements in creating maps that can be used to reduce fatalities, injuries or loss of property.

United States HSWG - FGDC

In September of 2005 the Department of Homeland Security released version 2.20 symbol set which was later incorporated into an ANSI Standard (ANSI INCITS 415-2006). This Symbology Standard was developed by the Federal Geographic Data Committee's Homeland Security Working Group (FGDC HSWG). From this group, a Symbology Subgroup with representatives from Federal, State, and local government worked to develop this Symbology standard and its usage. More information can be found at http://www.fgdc.gov/HSWG/. The standard is currently working its way through standards processes of ANSI and the Department of Homeland Security. ^[4]

Canada EMS

The Emergency Mapping Symbology was funded by GeoConnections, a Canadian government program that is national in scope. EMS is designed to support emergency management applications across Canada, including the national Multi-Agency Situation Awareness Systems (MASAS). EMS is part of efforts to create a Common Operational Picture both with emergency management agencies and with the public at large. It targets Web applications, but can also be used with traditional desktop applications.

The symbols are tailored to Canadian requirements for situational awareness reporting, first response, natural hazards assessment, public alerting, and critical infrastructure protection. The symbols are already being used by federal and provincial agencies, and are a valuable resource for Canada's Multi-Agency Situational Awareness System initiative, enabling emergency management organizations to share geospatial incident, event and alert information within the context of a national common operational picture. Although the dataset is designed to meet needs in Canada, very few of the symbols are specific to Canada. Most symbols are applicable globally. As discussed elsewhere, the work has been heavily influenced by similar efforts carried out in other countries. What distinguishes the EMS symbol set is its design, which follows a set of design principles that make it particularly suitable for Web applications by both trained and untrained personnel alike.

The development of EMS was strongly influenced by three primary sources:

HSWG - Homeland Security Working Group (ANSI INCITIS 415-2006 and the related mil spec: MIL-STD 2525C)

CAP-CP - Canadian Profile of the Common Alerting Protocol

NIDM - Canadian National Infrastructure Data Model (which was heavily influenced by the US-Canada Cross-Border Infrastructure Plan)

Thirty-seven organizations contributed to the development of the symbology. These included federal agencies in Canada and the United States, provincial and municipal emergency management organizations, emergency management software vendors, consulting companies, and universities. Further information can be obtained at (http://emsymbology.org).

[edit] References

[edit] Further Reading

• ESRI ArcGIS Desktop Help - An Overview of the Symbology Toolset]
• Military symbology, Military ClipArt Library. Retrieved May 4, 2010, from U.S Army Fort Sill website
• USGS - Topographic Map Symbols]
• The Atlas of Canada - Map Symbology
• Symbols.net - Map Symbols
• The Unofficial ArcInfo/ArcView Symbol Page
• WikiTravel - Common Map Symbols
• Cartographic representations