What is Geographic Information Systems (GIS) ?

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What is GIS?

Geographic Information Systems (GIS) store, examine, and picture information for geographic situations on Earth’s surface.

GIS represents Geographic Information Systems and is a PC based device that looks at spatial connections, examples, and patterns in geology.

It was involved back in 1854 (without PCs obviously!) to plan an illness flare-up in the City of London. Generally, we actually utilize this kind of spatial examination today yet in a more complex manner.


Information without spatial reference doesn’t give geographic setting. What’s more, without geographic setting, you can’t completely comprehend the world that we live in today.

That is the reason we really want Geographic Information Systems (GIS) and why it’s having a significant effect in our regular routines (that you may not take note).

READ MORE: The Power of Spatial Analysis: Patterns in Geography

What is GIS Mapping?

GIS Layers

GIS mapping produces visualizations of geospatial information. The 4 main ideas of Geographic Information Systems (GIS) are:

  • Create geographic data.
  • Manage it in a database.
  • Analyze and find patterns.
  • Display it on a map.

Because viewing and analyzing data on maps impacts our understanding of data, we can make better decisions using GIS.

It helps us understand what is where. The analysis becomes simple. Answers become clear.

Because you don’t fully understand your data until you see how it relates to other things in a geographic context.

What are the Use Cases of GIS?

Every day, GIS powers millions of decisions around the world. It makes a big impact on our lives and you might not even realize it. For example, we use GIS for:

  • Pinpointing new store locations
  • Reporting power outages
  • Analyzing crime patterns
  • Routing in car navigation
  • Forecasting and predicting weather

These 1000 GIS applications illustrate all the potential use cases of Geographic Information Systems.

How To Visualize Geography with Maps

I think you’ll agree:

It’s REALLY hard to visualize latitude and longitude coordinates from a spreadsheet.

City Latitude Longitude
Seattle 47.5° -122.3°
New York 40.7 -73.9°
Miami 25.8° -80.2°
Los Angeles 33.9° -118.2°

But when you add these positions on a map, suddenly spreadsheets come to life.

Locations Map

That’s because maps make geographic information easier to understand.

When you have geographic context, you don’t only see where they are on a map. But you can:

  • Calculate how far points are from each other
  • Check if points are clustered for patterns and trends
  • Find the optimal route between cities

Components of Geographic Information Systems

The 3 main components of Geographic Information Systems are:

1. Data

GIS stores location data as thematic layers. Each data set has an attribute table that stores information about the feature. The two main types of GIS data are raster and vector:

Raster Pixels


Raster data look like grids because they store data in rows and columns. They can be discrete or continuous. For example, we often represent land cover, temperature data, and imagery as raster data.

Editing Trace


Vectors are points, lines, and polygons with vertices. For example, fire hydrants, contours, and administrative boundaries are often vectors.

2. Hardware

Hardware runs GIS software. It could be anything from powerful servers, mobile phones, or a personal GIS workstation. The CPU is your workhorse and data processing is the name of the game. Dual monitors, extra storage, and crisp graphic processing cards are must-haves too in GIS.

3. Software

ArcGIS and QGIS are the leaders in GIS software. GIS software specializes in spatial analysis by using math in maps. It blends geography with modern technology to measure, quantify and understand our world.

Drive Decisions with Spatial Analysis

Never before have we had more pressing issues in need of a geospatial perspective. For example, climate change, natural disasters, and population are all geographic in nature. These global issues need location-based knowledge that can only come from a GIS.

Most people think GIS is only about “making maps”. But we harness the power of GIS because of the insights of spatial analysis. We use spatial analysis through math in maps. Spatial analysis is difficult with paper maps so that’s why we need GIS. Here are examples of spatial analysis:


The buffer tool generates a polygon around features at a set distance. By creating buffers, you can find the surrounding features that are within buffers.


Hot Spot

Hot spots highlight areas that have clusters of points. Whereas cold spots have a small density of points.

IDW Power 2

Build Your Career in Geomatics

GIS Percent 80% 20%

This quote means that if you take 80% of all government data, 80% has a geographic context. This quote originated from Robert Williams in his paper “Selling a geographical information system to government policymakers.”[1]

But recently, researchers have cut this percentage to 60% in 2012.[2] Either way, geography is a big component of data.

From planning a pipeline to navigating ships, spatial problems need spatial thinkers. This is why Geographic Information Systems has expanded into countless disciplines. GIS careers are booming for:

  • CARTOGRAPHERS create maps. In fact, the origin of “cartographer” comes from charta which means “tablet or leaf of paper” and graph “to draw”
  • DATABASE MANAGERS store and extract information from structured sets into spatial databases.
  • PROGRAMMERS write code and automate redundant GIS processes. For example, GIS programming languages include Python, SQL, C++, Visual Basic, and JavaScript.
  • REMOTE SENSING SPECIALISTS use aerial, satellite imagery, and remote sensing software.
  • SPATIAL ANALYSTS use geoprocessing tools to manipulate, extract, locate and analyze geographic data.
  • LAND SURVEYORS measure the 3-dimensional coordinates on the land.

READ MORE: GIS Salary Expectations: Climb the GIS Career Ladder

80% of the informational needs of local government are related to geographic location.

GIS All Started by Mapping Cholera

Cholera Map

In 1854, cholera hit the city of London, England. No one knew where the disease started. So, British physician John Snow started mapping the outbreak.

It wasn’t just the disease. But he also mapped out roads, property boundaries, and water lines.

When he added these features to a map, something interesting happened. He noticed that cholera cases were only along one water line. This was a breakthrough that connected geography to public health safety. But it wasn’t only the beginning of spatial analysis. It also marked the start of epidemiology, the study of the spread of disease.

In 1968, a man by the name of Roger Tomlinson started piecing together modern computing with maps. In fact, he first coined the term “GIS” in his paper “A Geographic Information System for Regional Planning“.[3] At this moment, GIS truly became a computer-based tool for storing map data. In 2014, Roger Tomlinson later passed away and will always be remembered as the “father of GIS”.

Source gisgeography.com
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