What is Geographic Information Systems (GIS)?

What is GIS?
What is GIS?

Geographic Information Systems (GIS) Connects Geography with Data

Every day, millions of decisions are being powered by Geographic Information Systems (GIS)…

From pinpointing new store locations… to predicting climate change… to reporting power outages… to analyzing crime patterns.

You might be wondering: But why use GIS?

Because geographic problems require spatial thinking.

In a GIS, you connect data with geography. You understand what belongs where. Because you don’t fully understand your data until you see how it relates to other things.

What is the definition for GIS?

Geographic Information Systems is a computer-based tool that analyzes, stores, manipulates and visualizes geographic information on a map.

Never in the history of mankind have we had more pressing issues in need of a geospatial perspective. These global issues require pervasive, complex, location-based knowledge that can only come from a GIS.

Long story short:

Geographic Information Systems really comes down to just 4 simple ideas: Create geographic data. Manage it. Analyze it and… Display it on a map. These are the primordial functions of a GIS.

Visualize Data by Making Spreadsheets Come to Life

I think you’ll agree:

It’s REALLY hard to visualize the locations of latitudes and longitudes coordinates from a spreadsheet.

Latitude and longitude table
Attribute table

But when you add these positions on a map, it’s like magic to the reader.

Latitude and Longitude on a Map
Latitude and Longitude on a Map

Everyone knows that maps make geographic information easier to understand.

So what exactly do you need to make your spreadsheets (and other spatial information) come to life?

1. Hardware – Hardware ranges from powerful servers to mobile phones. The CPU is your workhorse. Data processing is the name of the game. GIS analysts often need dual monitors, boatloads of storage and crisp graphic processing cards.

2. Software – The GIS software options out there seem endless. From ArcGIS, QGIS, GRASS GIS, SuperGIS, SAGA GIS to JUMP GIS… The range of GIS products to choose from can get a bit “ridiculous” at times. Here’s a quick guide to get you started:

READ MORE: Your GIS Workstation – What to Upgrade? | Mapping Out the GIS Software Landscape

Drive Decision-Making in Real World Applications




Most people think GIS is all about mapping data. But governments, businesses and people are attracted to GIS like magnets because of the power of spatial analysis.

It’s been a gradual shift away from paper maps. Instead, they pay close attention to computer-based spatial data.

The more you think of it:

Some of the largest problems of our planet are best understood spatially – climate change, natural disasters and population dynamics.

How do you solve problems in a GIS? The answer is through spatial analysis. Spatial analysis gives perspective in understanding relationships between spatial and attribute data.

READ MORE: 1000 GIS Applications & Uses – How GIS Is Changing the World

Spatial analysis examples:

Q: How much forest is in a city boundary or study area?
A: Run a clip on land cover classification. Sum the area of forest grid cells.
Clip Tool
Clip Tool
Q: How many endangered species are within a 1 mile proximity of a proposed mine?
A: Run a buffer. Calculate the number of species in the buffer.
Buffer Tool
Buffer Tool

READ MORE: 7 Basic GIS Processing Tools Every GIS Analyst Should Know

Manage Geospatial Data for Cost-Efficiency

There’s nothing more painful than drawing by-hand thousands of features on paper maps. But this is how it use to be.




Spatial analysis is impossible, querying is unimaginable and don’t even think about turning off a layer on a paper map.

In GIS, information about the real world is stored and collected as thematic layers. These layers are all linked by geography. We save cost because of greater efficiency in record-keeping. We are able to pull data in and out and make powerful decisions with relative ease.

How does Geographic Information Systems capture real world features? GIS data is rasters (grids) and vectors.

Rasters often look pixellated because they are stored in rows and columns (grid). Rasters are divided into discrete and continuous.

Continuous rasters are grid cells with gradual changing data. Examples are digital elevation models (DEM) and temperature data.
Continuous raster
Continuous raster
Discrete rasters have distinct themes or categories. For example, land cover has discrete classes with clear boundaries. One grid cell represents a land cover class.
Discrete raster
Discrete raster

Vectors represent points, lines and polygons. Cities, fire hydrants, contours, roads, railways and administrative boundaries are often represented as vectors. Vectors are generally smooth, rounded features.

Vectors
Vectors

READ MORE: 10 Free GIS Data Sources: Best Global Raster and Vector Datasets

Build Your Career in Geomatics

GIS Data Layers - Geographic Information Systems
GIS Data Layers

If you thought a career in GIS meant only making maps, you’d be wrong.

From planning a pipeline, navigating ships to fighting wildfires… Spatial problems require spatial thinking. This is why Geographic Information Systems has expanded into countless disciplines.

Tech-savvy employers expect the complete package of GIS skills. From programming, remote sensing, surveying, database management to web development… The most successful GIS professionals build their careers with multiple skill sets.

  • Cartographers create maps. The origin comes from charta – “tablet or leaf of paper” and graph-”to draw”
  • Database managers store and extract information from structured sets of geographic data.
  • Programmers write code and to automate redundant GIS processes. Typical programming languages in GIS are Python, SQL, C++, Visual Basic and Java.
  • Remote sensing analysts use satellite or aerial imagery to map the Earth. Remote sensing is the study of attaining data without physically being there.
  • Spatial analysts uses techniques to manipulate, extract, locate and analyze geographic data. Spatial analysis examples include buffering, clipping and exploring the relationships between map feature.
  • Land Surveyors measure the physical and geometric characteristics of Earth. Surveyors accurately measure three-dimensional points on the land.

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

GIS All Started by Mapping Cholera

When you look at an old map, it’s like you are traveling back in time.

A map not only shows geography, but paints a story of importance or struggle.

Geographic Information Systems all started in 1854. Cholera hit the city of London, England. British physician John Snow began mapping outbreak locations, roads, property boundaries and water lines.

When he added these features to a map, something interesting happened:

He saw that Cholera cases were commonly found along the water line.

Cholera Map
John Snow’s Cholera Map

It was a major event connecting geography and public health safety. Not only was this the beginning of spatial analysis, it also marked the start of a whole field of study: Epidemiology – the study of the spread of disease.

It wasn’t until 1968, GIS evolved to using computers:

Roger Tomlinson first used the term “Geographic Information System” in his paper “A Geographic Information System for Regional Planning”. GIS became computer-based tools for storing and manipulating map-based land data.

Roger Tomlinson later passed away in 2014. He will always be remembered as the “father of GIS”.

READ MORE: The Remarkable History of GIS

80% of Data is Geographic

It had been estimated that 80% of the informational needs of local government policy makers are related to geographic location.Robert Williams

80% of Data is Geographic

So it turns out 80% might’ve been a bit of an exaggeration. Although it’s often used in publications and presentations, there’s really no evidence that 80% of data is location-based.

Using a quick list of professions, GIS finds a home in 100% of them (in one form or another):

Agriculture: Crop type mapping, precision farming, soil types
Archaeology: Ancient civilization discovery with remote sensing, depositional patterns
Architecture and design: Land planning, value-added tabular information
Business: Site selection, locational analytics, supply chain
Education: Visualizing data, decision support, record keeping
Engineering: Infrastructure data maintenance, CAD interoperability
Environmental studies: Environmental assessments, climate change analysis, groundwater contamination
Family and consumer science: Consumer profiling, data analytics
Forestry: Timber management, deforestation analysis, forest resource inventory
Human physical performance and recreation: GPS tracking, trail and park planning
Media and communication: Communicating stories with maps, targeting advertising campaigns
Law and crime: Investigative analysis, in-vehicle mobile mapping, predictive policing
Medicine and public safety: Disease mapping, disaster response, public health informatics
Military sciences: Locational intelligence, logistics management, spy satellites
Public administration: Public communication, urban and regional planning
Public policy: Decision support, socio-economic information
Real estate: Comparative real-estate analysis, market analysis
Social work: Public transportation availability, showing impacts and needs of services
Transportation: Optimal route selection, noise modelling, future travel modelling
Water resources: Watershed delineation and management, determining flow direction, assessing water quality

From A to Z, you’re looking at 20 professions who have adopted GIS technologies.

GIS and Remote Sensing in Wildfire Response

A wildfire hit Yosemite National Park in California in August 2013. All said and done, the extent of the fire was estimated to be 15 times the size of Manhattan island. This makes it the fourth largest wildfire in California history.

How is GIS used to respond to wildfires?
How do you use Geographic Information Systems? What are the steps to follow when solving a GIS problem?

Step 1. Question:
In this step, you ask a high-level question. This high-level question will guide you to obtaining the correct data, performing the analysis and examining the results.

As a land manager in Yosemite during a wildfire, how can we monitor the severity and effects of the wildfire? How can we monitor the recovery of the land?

Yosemite, California
Yosemite, California
Step 2. Capture:
You can acquire satellite remote sensing imagery to inspect real-time wildfire extents. Acquiring pre- and post- images to monitor wildfire damage. What ancillary data could be used such as roads, infrastructure and trails?
Yosemite National Park Pre-Wildfire
Yosemite National Park Pre-Wildfire (Landsat imagery courtesy of USGS/NASA Landsat)
Step 3. Analyze:
Satellite data provides vegetation (and fire fuel) information that is used to model fire behavior. Real-time satellite data is used to map potential risks to communities and determine post-fire effects.
Yosemite National Park Wildfire
Post-wildfire satellite image false-colored. Fire appears bright red, vegetation is green, smoke is blue, clouds are white, and bare ground is tan-colored. (Landsat imagery courtesy of USGS/NASA Landsat)
Step 4. Respond:
Communicate plans to wildfire responders saving time, money and lives. Plan future emergency by providing timely, accurate and relevant geospatial information as a data portal. Serve webmaps to fire managers with real-time fire perimeter data.
GIS Fire Perimeters
GIS Fire Perimeters

What Can GIS Do For You?

Geographic Information Systems has been designed to answer important questions about location, patterns, trends and conditions such as:

  • Where are features found? Points, lines and polygons. If you need to find the closest gas station, GIS can hold your hand there. Searching for an optimum location requires information on traffic volumes, zoning information and demographics over multiple sites.
  • What geographical patterns exist? Ecologists who want to know suitable habitat for elk can gain a better understanding by using GPS collars and forest inventory.
  • What changes have occurred over a given period of time? Never have we’ve been able to understand climate change before thanks to GIS and remote sensing technology. Safety concerns can be better evaluated using GIS such as understanding terrain slope and the probability an avalanche can occur.
  • What are the spatial implications? If an electricity company wants to build a transmission line, how will this affect nearby homes, the environment and safety. Most environmental assessments use GIS to understand the landscape.

You might ask yourself:

Haven’t geographers been answering these questions for centuries?

Yes, they have. But in the most part, geographers have not been able to answer these questions very well because of the lack of computing available and the volumes of data required to understand features geographically.

Mapping the Future with Geographic Information Science

GIS Science

Paper maps will be completely obsolete in 10 years.

Bold statement? Definitely.

But take a step back and ask yourself:

How will GIS grow in upcoming years?

This is a question that can only be answered with Geographic Information Science.

Geographic Information Science provides all the building blocks for Geographic Information Systems. It draws from computer science, mathematics, geography, statistics, cartography, and geodesy. GIScience incorporates the knowledge from these fields into Geographical Information Systems.

  • Geographic Information Systems connects what with the where.
  • Geographic Information Science discovers how.

Geography Information Science defines how concepts are used in Geographic Information Systems. It conceptualizes how spatial data is being stored, collected and analyzed.

Why GIS is not Going Away Anytime Soon

What Is GIS
Click to expand GIS infographic

Geographic Information Systems allows us to make better decisions using geography.

Analysis becomes simple.

Answers become clear.

Everyday GIS makes an impact on your life and you might not even realize: GPS navigation, weather maps, ambulance dispatch. GIS is used because it helps us understand the world around us.

Cartographers, spatial analysts, surveyors, webmap programmers and remote sensing analysts are GIS-based professions. 80% of data may or may not be location-based. But there’s no arguing that GIS is being integrated into more and more professions.

When the natural resources community first started manually interpreting aerial photos recording inventories on paper maps…to say the least: it was a tedious process.

What did it really need?

A spatial database to manipulate location data. Where are the forests, mines and cities? A table to store attributes about the data. What types of forests are they? When was city settlement? Who owns the mines?

What’s the bottom line?
Viewing and analyzing data geographically impacts our understanding of data.

A geographic information system (GIS) lets us visualize, question, analyze, and interpret data to understand relationships, patterns, and trends.

References:
Williams, Robert (1987), Selling a geographical information system to government policy makers. Papers from the 1987 Annual Conference of the Urban and Regional Information Systems Association

5 Comments on What is Geographic Information Systems (GIS)?

  1. I described it all and lost it before it was posted. What I said was I hope to integrate GIS with Surveying since these should be two complementary tools. Maybe it’s just that those surveyors are “Out standing in their fields”. After 4 weeks, I’ve found that there is a lot more to it. “Gee. I thought it was going to be Simple” (GIS)

  2. Yes the infographic was created here. Please feel free to reuse if you’d like. If you can cite us somehow, that would be good… but you don’t have to

  3. This is so informative. I never felt sleepy reading. Everything is well stated. Thanks! I could use it in our capstone.

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