Geographic information system

A geographic information system (GIS) is a powerful combination of computer hardware and software that helps us store, manage, analyze, edit, and visualize information about places on Earth. This information, called geographic data, can include anything from the location of schools and parks to the paths of rivers and mountains.

GIS can also use a special type of database called a spatial database, but this isn't required. In a bigger sense, a GIS includes the people who use it, the ways they work, and all the knowledge about how to understand and use location data properly. There are even whole fields of study, like GIScience, that focus on the science behind these systems.

People use GIS in many different areas, such as city planning, helping ships and trucks find the best routes, studying nature and wildlife, and even in businesses that need to know where their customers live. Because GIS lets us connect information using location as a key piece of information, it helps us understand our world better. By recording where and when things happen — using details like longitude, latitude, and elevation — GIS can link many different pieces of data to real places on Earth. This makes it a valuable tool for scientists, planners, and many others who need to study or manage our planet.

History and development

Digital geographic information systems began in the mid-1960s when Roger Tomlinson first used the term "geographic information system." Many ideas about geography that GIS uses are much older.

E. W. Gilbert's version (1958) of John Snow's 1855 map of the Soho cholera outbreak showing the clusters of cholera cases in the London epidemic of 1854

One early example of using maps to study health happened in 1832, when a map showed where cholera was spreading in Paris. In 1854, John Snow used maps to find the source of a cholera outbreak in London by marking where people who got sick lived and where water came from.

In the early 1900s, maps were made in layers, like vegetation on one layer and water on another. In the 1960s, the first full GIS was created in Ottawa, Canada, to help manage land resources. Later, more tools and software were developed to make GIS easier to use and more powerful.

GIS software

Relationship between general GIS, distributed GIS, Internet GIS, Web GIS, Mobile GIS, Cyber GIS, and computer cartography.

A geographic information system (GIS) is a special type of computer setup used to handle maps and location data. GIS software is the program part of this system. It helps people work with maps and find useful information from them.

One well-known example is Esri's ArcGIS, which includes tools like ArcGIS Pro and older versions such as ArcMap. Other programs include Autodesk, MapInfo Professional, and free options like QGIS, GRASS GIS, MapGuide, and Hadoop-GIS. These programs let users add, change, study, and show geographic data.

With the Internet, GIS has also moved to online services. Now, people can use GIS tools through websites and apps without installing special software on their computers. This is called distributed GIS and includes services like ArcGIS Online. Some computer systems also add map-related features directly into other programs, helping to connect maps with everyday software.

Geospatial data management

Example of hardware for mapping (GPS and laser rangefinder) and data collection (rugged computer). The current trend for geographical information system (GIS) is that accurate mapping and data analysis are completed while in the field. Depicted hardware (field-map technology) is used mainly for forest inventories, monitoring and mapping.

A geographic information system (GIS) is a tool that helps us store, manage, and analyze data about places on Earth. It uses computer programs to handle information linked to locations, like maps and satellite images. This system can show us where things are, how they change over time, and how different pieces of information relate to each other.

GIS works by connecting data to specific spots on the planet. For example, it can tell us the height of mountains, the flow of rivers, or even the number of people living in a city. This helps scientists, planners, and many others understand patterns and solve problems. People use GIS for many things, from making maps to studying climate change and planning new roads.

Spatial analysis

Further information: Spatial analysis

GIS spatial analysis is a fast-changing field. GIS tools now commonly include special analysis features, either built-in, added on, or created by users. These tools help people study and understand places better. They can show useful information in new ways, making it easier to share geographic knowledge.

Geoprocessing is a way GIS changes spatial data. It takes information, does something with it, and shows the result. Common tasks include combining maps, picking out certain areas, and working with shapes and patterns of land. This helps people make better decisions.

Many tasks involve studying the land’s surface, like how water moves or what areas might flood. Tools can show the steepness of hills, which way a slope faces, and where water might flow. These tools help plan for things like building or protecting the environment.

Other tools can measure distance between places, show areas within a certain travel range, and combine different maps to see new patterns. GIS can also help estimate where things might be based on known points, like guessing a rain amount from nearby weather stations. These tools make it easier to understand and plan for many real-world problems.

Data output and cartography

Main articles: Cartographic design and Digital mapping

Cartography is the art of making maps to show geographic information. Today, most maps are made using computers and special software called geographic information systems (GIS). This software helps people change how the information looks on the map.

Maps have two main purposes. First, they show results of studies in a way that helps people make decisions. For example, maps can show what might happen in different situations. Second, maps can give extra details, like a list of addresses near a certain place.

Traditional maps show the world using symbols to represent real objects. For example, topographic maps use lines to show the shape of the land. Modern computers can make maps that show the height of land more clearly, helping people understand the land better.

Today, many people use web maps like Google Maps and Bing Maps, or OpenStreetMap. These maps let everyone see a lot of geographic information easily. During big events, like the COVID-19 pandemic, web maps helped share important information quickly. Some of these maps let people create their own map tools using special instructions called application programming interfaces.

However, anyone can make web maps now, even without special training. This can sometimes lead to maps that are not clear or could confuse people.

Uses

Since the 1960s, geographic information systems (GIS) have been used in many different ways. They help us understand where things are and how they relate to each other. GIS can be used for learning new things, like studying why a business succeeded or failed, or for making decisions, like planning where to build a new park.

GIS is used in many areas, from studying the natural world, like mountains and rivers, to understanding human activities, like cities and transportation. It helps governments, businesses, and even individuals make better choices. For example, it can show the best route to a friend's house or help plan where to send help during a storm.

Other aspects

Main article: Open Geospatial Consortium

OGC standards help GIS tools communicate.

The Open Geospatial Consortium (OGC) is a group of companies, government agencies, and universities that work together to create rules for using geographic information. These rules help different computer programs work together, making it easier to share maps and location data.

GIS can also show how things change over time. For example, scientists can use satellite images to watch how plants grow or shrink over months, helping to find patterns like drought. This lets researchers see how the world changes and plan for the future.

Societal implications

Main articles: Neogeography and Public participation GIS

As GIS becomes more common in decision making, people have started looking at how it affects society and politics. GIS can sometimes be used to change how things look to help certain people or groups. During the COVID-19 pandemic, GIS was very important because it helped health agencies and scientists see and track how the disease was spreading in real time. The Johns Hopkins University COVID-19 Dashboard was one of the most well-known GIS tools, showing how web-based maps can help guide decisions and keep people informed. Using GIS can also help build trust between people and the government. Other topics include copyright, privacy, and censorship. One hopeful way to use GIS is to let more people take part in decisions that affect them.

GIS has become useful in schools, helping students understand geography better by using real data. It can make learning more interesting and help students think about places and spaces in new ways. Many schools now offer courses about GIS to help students learn these skills.

In local government, GIS helps many different jobs work better. For example, it helps with planning where new businesses might go, keeping communities safe, managing parks, and tracking important services like water and electricity. It also helps with planning schools and keeping track of important information like voting records. Sharing this information openly helps people stay informed and involved in their communities.

GIS is also important for studying ancient places and protecting important historical sites. It helps experts keep track of these places and understand how changes might affect them.