If you have ever used Google Maps or GPS when traveling, then you've experienced the power of a geographic information system (GIS).

A GIS is a computer system for capturing, storing, checking and displaying data related to positions on Earth.

It can use any information that includes location. The location can be expressed in many different ways, such as latitude and longitude or address.

Many different types of information can be compared and contrasted using GIS, and we can find out how that information relates to each other. It tells us about the landscape and people around us. GIS is an important tool for many different jobs.

However, there are challenges that come with GIS technology. Though communities can save money by storing GIS data on a cloud service, GIS is still expensive to set up and maintain. Some communities cannot access GIS because of the cost. It is also hard to learn how to use these systems. People have to be trained in how to create GIS maps and use them properly. Old or inaccurate data can also cause problems in GIS.

There are benefits and challenges when citizens use GIS. Citizen users provide on-the-ground data to these systems. These users are not technology experts and are sometimes called citizen geographers. Information provided by these users can help solve problems quickly. For example, people can report damage to buildings or injuries to others during a natural disaster. This can help rescue workers assist the public faster. Social justice organizations can use GIS in certain neighborhoods to gather data and better serve their communities. But there is concern over data privacy and security. People could access the data and use the information for harmful purposes. Someone could, for example, track another individual’s movements.

But data policies created by the government have the potential to overreach. For instance, GIS data could be used to enforce harmful stereotypes about people from marginalized communities. This could lead to more discrimination for these communities. While GIS can be used to fight racism and achieve social justice goals, the people who have access to GIS data must have proper data protections to create buy-in and trust with everyone in the community.

Data Capture

Data Formats

GIS data comes in many forms.

One example is cartographic data, or map data. This might include such information as the location of rivers, roads, hills and valleys. Cartographic data might also include survey data, or mapping information, which can be directly entered into a GIS.

Interpreting photographs is a major part of GIS. Photo interpretation involves analyzing photographs from above and assessing the features that appear.

Digital data can also be entered into a GIS. For example, computer data collected by satellites can show how land is used, plus the location of farms, towns and forests. Satellites can also use a GIS to capture images in a tool called remote sensing.

Finally, GIS data can also be collected from tables or spreadsheets. One example of this is population demographics. This is when people are grouped into certain categories. Some examples are age, income and ethnic background, or even internet browsing history.

GIS technology allows all these different types of information to be overlaid on top of one another on a single map. Location is the key data point that connects seemingly unrelated information.

Spatial Relationships

GIS technology can be used to display spatial relationships and linear networks.Spatial relationships may display topography, such as farmland and streams. They may also show patterns of how land is used, such as the location of parks and neighborhoods.

Examples of linear networks are roads and rivers. A line on a map might indicate a road or highway. With GIS layers, however, that road may indicate the boundary of a school district, public park or other land-use area.

GIS must make the information from all the various maps and sources fit together on the same scale. A scale is the relationship between the distance on a map and the actual distance on Earth.

Often, GIS must manipulate and move data because different maps have different projections. A projection is a way of moving information from Earth's curved surface to a flat piece of paper or computer screen. Different types of projections accomplish this task in different ways. Whenever this happens, there is some distortion. You can't put a curved, three-dimensional shape onto a flat surface without stretching some parts and shrinking others.

There is an example of this in the Cartographer's Dilemma video. The Mercator map, made in 1569, makes Western Europe look bigger than it actually is. This reflects the mapmaker’s bias that Europe was the most important continent. Though mapmakers are working on more accurate maps, there will always be some distortion.

GIS takes data from maps that were made using different projections. It combines them so all the information can be displayed using one common projection.

GIS Map

GIS maps are used for many purposes in different fields. Local and federal governments use them to learn more about the communities they represent. Federal governments can use a GIS to track the effects of different policies and laws. GIS maps can also help government agencies by displaying what artificial features are near certain natural features. For example, they can show which homes and businesses are in areas prone to flooding. This can help local governments prepare for natural disasters.

GIS maps are also useful in science. With GIS technology, researchers can study changes over time. They can use satellite data to study topics such as the movement and disappearance of ice cover in the North Pole. GIS can produce three-dimensional images. This is helpful to geologists studying earthquake faults. Additionally, engineers use GIS technology to support the design, implementation and management of communication networks for cell phones. They also use it to create the infrastructure necessary for internet connectivity.

GIS can even be beneficial outside of government and science purposes. Many retail businesses use GIS to help them determine where to locate a new store. Museums use GIS to gather information about where their visitors are coming from. They also use GIS to create maps of the museum and its interactive exhibits.

There are many opportunities for governments, businesses and individuals to use GIS to make life easier. But there are also challenges with privacy and data misuse. The key to the future of GIS is to earn trust and buy-in from users who are sharing their data.