English:Geographic Information Systems
Geographic Information Systems
Introduction
A Geographic Information System (GIS) is a computer-based system for working with information that is connected to places on Earth. A GIS can collect, store, check, organize, analyze, and display geographic data. Instead of showing only where things are, it can help you investigate questions such as: Where are the safest walking routes to school? Which neighborhoods are farthest from parks? Where has a river changed course? Which places are most at risk during a flood?
You probably already meet GIS ideas in everyday life. Digital maps, route planners, weather maps, delivery tracking, public-transport maps, wildlife maps, and emergency maps all combine locations with information. In this aiMOOC you will learn how GIS turns location data into useful evidence and how to use maps responsibly.
Learning goals for Grades 7–8: By the end of the course, you should be able to explain what GIS does, distinguish vector and raster data, describe map layers and attributes, use coordinates to locate features, interpret simple thematic maps, plan a small GIS investigation, evaluate data quality, and discuss privacy and fairness when geographic data are collected or shared.
The image above shows a central GIS idea: separate kinds of information can be organized as layers and viewed together.
What Makes GIS Different from an Ordinary Map?
A paper map is a useful representation of places and features. A GIS goes further because the map is connected to data. You can turn layers on and off, search for features, compare locations, calculate distances or areas, select places that match conditions, and create new maps from the results.
A GIS usually works with two connected parts of a feature:
- Spatial data: Information about where something is and what shape it has.
- Attribute data: Information that describes the feature, such as a road name, tree species, population, or opening time.
Imagine a school map. The location of each drinking fountain is spatial data. A table could store attributes such as whether the fountain works, when it was checked, and whether it is accessible. Linking the map and the table allows you to ask more useful questions than either source could answer alone.
Layers: Organizing Geographic Information
GIS data are often arranged in layers. One layer might show roads, another rivers, another buildings, another population, and another elevation. Because the layers refer to the same geographic area, they can be compared or combined.
For example, a town planning a new bicycle route could compare layers for roads, schools, steep slopes, traffic volume, parks, and existing bicycle paths. The goal is not simply to put many things on one map. The goal is to choose relevant data and use it to answer a clear geographic question.
A basemap provides background reference information such as streets, place names, land, and water. Thematic layers are then added to show the information that matters for a particular investigation.
A GIS Workflow
A simple GIS investigation can be organized as a repeating cycle:
- Geographic question: Ask a question that depends on location, pattern, distance, direction, or area.
- Data collection: Find or collect information that can help answer the question.
- Data preparation: Check names, units, locations, dates, missing values, and errors.
- Spatial analysis: Compare or process locations and attributes.
- Map design: Choose symbols, labels, colors, scale, title, legend, and other elements that communicate the result.
- Evaluation: Check whether the result is supported by the data and explain limitations.
Geographic Data
GIS works with geospatial data: data connected to a position on or near Earth. Some data are created directly in the field. Other data come from government surveys, satellites, aerial photographs, sensors, scientific studies, or community mapping projects.
Before using a dataset, ask four questions: Who created it? When was it created or updated? What exactly does each value mean? How accurate and complete is it for your purpose?
Coordinates and Location
A coordinate system gives a consistent way to describe position. Latitude and longitude are commonly used to identify positions on Earth. Latitude measures position north or south of the Equator, while longitude measures position east or west of the Prime Meridian.
A GIS may also use a projected coordinate system, which represents the curved Earth on a flat map. Every flat map projection changes some combination of shape, area, distance, or direction. This is why choosing a suitable projection matters when measurements are important.
Do not confuse coordinates with addresses. An address is a human-readable description of a place; coordinates are numerical positions. Geocoding is the process of turning an address or other place description into a geographic location that can be mapped.
GPS and Field Data
A GPS receiver uses signals from satellites to estimate its position. Phones, tablets, watches, vehicles, and dedicated receivers can use satellite navigation. In a school GIS project, a mobile device might be used to record the coordinates of trees, bicycle racks, litter bins, or accessibility features.
Location measurements are never automatically perfect. Buildings, trees, signal conditions, device quality, and the way data are collected can affect accuracy. For a careful investigation, record when and how you collected each point and avoid claiming more precision than your method supports.
Safety and privacy rule: Do not publish a classmate's home location, daily route, precise meeting place, or other sensitive location data. Collect only the information needed for the learning task, get appropriate permission, and share results at a safe level of detail.
Remote Sensing
Remote sensing means gathering information about an object or area from a distance, often using sensors on satellites, aircraft, or drones. Satellite imagery can show patterns in vegetation, water, land cover, ice, fires, cities, and many other features. When imagery is georeferenced, it can be used as raster data in GIS.
Remote-sensing images do not always look exactly like photographs taken by the human eye. Sensors can measure different parts of the electromagnetic spectrum, and images can be processed to emphasize particular features. Interpretation therefore depends on knowing what the image represents and when it was collected.
Vector and Raster Data
Two important ways to represent geographic information are vector and raster data.
Vector Data
Vector data represent features with geometry.
- Point: A single location, such as a bus stop, tree, well, or weather station.
- Line: A path or narrow feature, such as a road, river, trail, or railway.
- Polygon: An area with a boundary, such as a lake, park, school site, neighborhood, or country.
Each vector feature can have attributes. A park polygon might have attributes for name, area, opening hours, sports facilities, or tree cover. A road line might have attributes for road name, speed limit, surface, or traffic count.
Vector data are especially useful when features have clear locations or boundaries and when individual objects need to be selected or described.
Raster Data
Raster data divide space into a grid of cells, also called pixels. Each cell stores a value. The value might represent elevation, temperature, rainfall, land cover, or the brightness recorded by a satellite sensor.
Raster data are useful for phenomena that vary continuously across an area. Cell size affects detail: smaller cells can represent finer spatial variation, while larger cells summarize larger areas. Higher detail does not automatically mean better information; the data still need to be accurate, relevant, and suitable for the question.
Choosing Between Vector and Raster
Suppose you are mapping a school campus. Building footprints and paths are naturally represented as vectors. A continuous surface such as elevation or temperature is often represented as raster data. Some information can be represented either way, but the best choice depends on what you want to analyze.
A strong GIS user does not ask, "Which format is always better?" Instead, ask, "Which representation best matches this geographic phenomenon and this investigation?"
Attribute Tables and Data Quality
A GIS layer often has an attribute table. Each row usually represents a feature, and each column stores a field such as a name, category, count, date, or measurement.
For example, a layer of school trees might include fields for species, trunk size, health condition, survey date, and whether the tree provides shade over a path. You could filter the table to find trees in poor condition or select all trees surveyed on a certain day and immediately see those features on the map.
Good analysis depends on good data. Watch for missing values, duplicated features, wrong coordinates, inconsistent spelling, outdated information, mixed measurement units, and unclear categories. A beautiful map can still be misleading if its data are weak.
Metadata
Metadata are information about data. Useful metadata can explain who created a dataset, when it was collected, how it was measured, which coordinate system it uses, what each field means, and what limitations are known.
Treat metadata like the label on a science experiment. Without it, another person may not know how the result was produced or whether the data are suitable for a new purpose.
Spatial Analysis: Asking Where
Spatial analysis examines locations, attributes, patterns, and relationships. The exact tools can be complex, but the core questions are understandable:
- Proximity analysis: What is near something else?
- Overlay analysis: Where do two or more conditions occur in the same place?
- Network analysis: What route connects places through a network such as streets?
- Density analysis: Where are events or features concentrated?
- Change detection: How has a mapped pattern changed over time?
For example, imagine a town wants to choose locations for new shade shelters. A class could compare where students wait for buses, where there are few trees, where sidewalks are wide enough, and where shelters would not block intersections. GIS helps organize the evidence, but people still need to decide which factors matter and how much weight to give each one.
Overlay: Combining Layers
Overlay means comparing layers that cover the same geographic area. You might overlay a flood-risk layer with a building layer to identify structures that could be exposed to flooding, or combine habitat, roads, and protected areas to study possible wildlife corridors.
The output of an overlay is not automatically a final answer. It is evidence created from particular datasets and rules. Always explain which layers were used and what limitations they have.
Buffering and Proximity
A buffer is an area drawn at a chosen distance around a map feature. A buffer around a river might represent a protection zone. A buffer around a school could help explore which homes or bus stops are within a certain distance.
Distance alone may not describe real travel. A place that is close "as the crow flies" can be difficult to reach if a river, fence, motorway, or steep slope blocks the route. For travel questions, network data may be more useful than a simple straight-line buffer.
Map Design and Communication
GIS is not only about analysis; it is also about communicating evidence. A clear map should help readers understand what is being shown, where it is, and how to interpret the symbols.
Useful map elements can include a descriptive title, legend, scale information, source note, labels, and orientation. Not every map needs every possible element, but every design choice should support the map's purpose.
Thematic Maps
A thematic map emphasizes a particular subject. A choropleth map uses different shades or colors to represent numerical values for areas, such as population density by district.
When using a choropleth map, check what the colors represent. Total counts and rates are not the same. For example, coloring districts by total number of people can produce a very different pattern from coloring them by people per square kilometer. The classification method and data ranges can also influence how a pattern looks.
Symbols, Scale, and Generalization
Point symbols, line styles, and area colors should be easy to distinguish. A legend should explain unfamiliar symbols. Labels should be readable without covering important data.
Map scale describes the relationship between distances on the map and distances on the ground. When you zoom out, a GIS often simplifies detail so the map remains readable. This process is called generalization. A street that matters on a neighborhood map may disappear on a map of the whole country.
Web Maps and Collaborative Mapping
Many GIS products are shared as interactive web maps. A web map can allow users to zoom, search, switch layers, click features, or view updated data. Some platforms also allow groups to collect or edit geographic information together.
OpenStreetMap is an example of a collaborative geographic database created by contributors. Community mapping can fill gaps and provide detailed local knowledge, but contributors must follow project rules, respect evidence, and avoid adding private information.
GIS in Everyday Life and Society
GIS supports decisions in many fields. Emergency services can map hazards and response routes. Ecologists can study habitats. Transport planners can examine traffic and public transit. Archaeologists can record sites. Public-health teams can investigate spatial patterns while protecting personal information. Businesses can study service areas. Utilities can manage networks such as water pipes and power lines.
In school, GIS can connect Geography, Earth science, Environmental science, Mathematics, Computer science, Civics, and Data literacy. It turns maps into questions that can be tested with evidence.
GIS and Environmental Questions
Environmental problems are often spatial. Flooding, heat, pollution, habitat loss, soil erosion, and access to green space all vary from place to place. GIS can help you compare those patterns with natural and human features.
A useful school question might be: "Which parts of our school grounds become hottest on sunny days, and how is that related to shade?" You could map measurement points, add tree-cover or building layers, compare temperatures, and propose locations where added shade might have the greatest benefit.
GIS and Communities
GIS can reveal differences in access to services such as parks, libraries, clinics, public transport, or safe walking routes. These analyses can support community discussions, but the map does not decide what is fair. People need to examine how the data were collected, who may be missing, what measure of access is being used, and whose needs are being considered.
This is an important lesson in data ethics: geographic data can support good decisions, but it can also expose private information, repeat bias, or create false confidence if used carelessly.
Reading GIS Critically
A map is an argument made with selected data and design choices. Before trusting a GIS map, ask:
- Source evaluation: Who created the map and for what purpose?
- Data date: When were the data collected or updated?
- Completeness: Which places or people might be missing?
- Measurement: What exactly is being counted or calculated?
- Scale: Is the map detailed enough for the claim?
- Uncertainty: How precise are the locations and values?
- Design choices: Could colors, categories, symbols, or boundaries change how the pattern appears?
A responsible GIS user explains limitations rather than hiding them.
Mini Investigation: Mapping a School Question
You can carry out a simple GIS-style investigation even without advanced software. Choose a question that depends on location, such as where litter collects, where bicycle parking is most needed, where shade is available, or where noise levels are highest.
First, define what you will measure and how. Create a simple base map of the school grounds. Mark observation points using non-sensitive locations. Record attributes in a table. Use the same units and categories at every point. Then symbolize the results on your map and look for patterns. Finally, write a conclusion that answers the question and names at least two limitations.
If your school permits digital tools, you can use a spreadsheet with coordinates, a web-mapping platform, or a desktop GIS such as QGIS. The investigation process matters more than the software: ask a clear question, collect suitable data, analyze carefully, and communicate responsibly.
Key Vocabulary
- Geographic Information System: A computer-based system for collecting, managing, analyzing, and displaying data connected to locations.
- Geospatial data: Information linked to positions on or near Earth.
- Layer: A set of related geographic features or values displayed together.
- Attribute: A descriptive value connected to a geographic feature.
- Vector data: Geographic data represented with points, lines, and polygons.
- Raster data: Geographic data represented as a grid of cells.
- Coordinate: A value or set of values used to identify a position.
- Geocoding: Converting a place description such as an address into a geographic location.
- Remote sensing: Collecting information from a distance using sensors.
- Spatial analysis: Examining locations, patterns, attributes, and relationships to answer geographic questions.
- Metadata: Information that describes how a dataset was created, organized, and limited.
- Map projection: A method for representing Earth's curved surface on a flat map.
Interactive Tasks
Quiz: Test Your Knowledge
What makes GIS different from a simple static map? (It connects mapped locations with data that can be analyzed) (!It can only show satellite photographs) (!It never uses tables) (!It works without geographic locations)
Which vector geometry is most suitable for representing a bus stop? (Point) (!Line) (!Polygon) (!Raster)
Which kind of data is made of a grid of cells? (Raster data) (!Vector data) (!Attribute names) (!Metadata only)
What is an attribute in GIS? (Information that describes a geographic feature) (!A satellite that provides location signals) (!A line showing north on every map) (!A rule that removes map layers)
Why are GIS layers useful? (They allow related kinds of geographic information to be compared) (!They guarantee that all data are correct) (!They remove the need for a geographic question) (!They make every map use the same scale)
What does geocoding do? (It converts a place description into a geographic location) (!It converts a raster into a photograph) (!It measures the age of a dataset) (!It hides all map labels)
Which example is a suitable use of a buffer? (Showing an area within a chosen distance of a river) (!Correcting every error in an attribute table) (!Changing a satellite into a GPS receiver) (!Turning a paper map into a globe)
Why should you check metadata before using a dataset? (It can explain the source date method and limitations) (!It proves that every map conclusion is correct) (!It replaces the need to inspect the data) (!It makes all coordinates perfectly accurate)
What is a responsible rule for sensitive location data? (Collect and share only the detail needed for the task) (!Publish exact home locations for better precision) (!Ignore permission when a map is educational) (!Store personal routes without explaining the purpose)
Which question is an example of spatial analysis? (Which school entrances are closest to bus stops) (!How do you spell the word geography) (!What is the title of a textbook) (!Which keyboard has the largest space bar)
Memory Game
| Layer | A related set of geographic information that can be displayed together |
| Attribute | Descriptive information connected to a mapped feature |
| Vector | A data model using points lines and polygons |
| Raster | A data model using a grid of cells |
| Metadata | Information that explains the source method date and limitations of data |
| Buffer | An area created at a chosen distance around a feature |
Drag and Drop
| Match the correct terms. | Topic |
|---|---|
| Point feature | A drinking fountain on a school map |
| Line feature | A bicycle path through a park |
| Polygon feature | The boundary of a school playground |
| Raster surface | A grid showing temperature across a town |
| Attribute field | The condition rating stored for each tree |
...
Crossword Puzzle
| Layer | What GIS structure organizes one related set of geographic information? |
| Raster | What data model represents space as a grid of cells? |
| Vector | What data model uses points lines and polygons? |
| Attribute | What word means descriptive information connected to a feature? |
| Coordinate | What identifies a position using location values? |
| Projection | What method represents the curved Earth on a flat map? |
LearningApps
Cloze Text
Open-Ended Tasks
Easy
- Map Layer Hunt: Find a digital map that lets you switch layers on and off. Identify four layers and explain what question each layer could help answer.
- Point Line Polygon Sketch: Draw a simple map of an imaginary school area and represent at least three point features, three line features, and three polygon features. Add a legend.
- Map Critic: Choose one thematic map from a textbook, newspaper, or trusted website. Write a short paragraph explaining its purpose, data, symbols, and one limitation.
- GPS Interview: Interview an adult about one way they use location technology in daily life. Summarize the benefit and one privacy or accuracy concern without recording private locations.
Standard
- School Shade Survey: Measure or observe shade at several safe public points on school grounds, map the points, create an attribute table, and explain the spatial pattern you find.
- Open Data Comparison: Find two public maps of the same area from trustworthy sources. Compare their dates, layers, detail, and purpose, then explain which source better answers one question you choose.
- Neighborhood Map Story: Create a short illustrated map story about access to a non-sensitive public feature such as parks, libraries, or bus stops. Include a map, captions, and a source note.
- GIS Explainer Video: Produce a two-minute video that teaches younger students the difference between vector and raster data using examples you create yourself.
Advanced
- Site Selection Challenge: Design a GIS-style method for choosing a location for a new bicycle rack, shade shelter, or recycling station. Define at least four criteria, explain the layers needed, and justify your final choice.
- Community Mapping Interview: Interview a local planner, environmental worker, surveyor, emergency manager, or map user about how geographic data support decisions. Turn the interview into a one-page report and identify one data-quality challenge.
- Remote Sensing Change Study: Compare two openly licensed or public-domain satellite images of the same place from different dates. Mark visible changes, propose explanations, and distinguish observation from inference.
- Field Mapping Project: With school permission, visit a safe public place such as a park or town center, collect non-sensitive observations using a consistent method, create a digital or paper GIS-style map, and present a recommendation supported by your mapped evidence.
Learning Assessment
- GIS Investigation Design: Given a question about improving safe bicycle access to school, identify the layers and attributes you would need, explain how you would analyze them, and justify which data should not be collected for privacy reasons.
- Vector Raster Reasoning: For a map of trees, roads, elevation, and surface temperature, decide which features are best represented as vector or raster data and explain why each choice matches the phenomenon.
- Map Reliability Evaluation: Compare two maps that make different claims about the same area. Evaluate source, date, scale, classification, completeness, and uncertainty before deciding which claim is better supported.
- Spatial Analysis Transfer: Explain how overlay or proximity analysis could be used in a new context such as flood planning, wildlife protection, public transport, or emergency response. State what extra information decision-makers would still need.
- Ethical Mapping Scenario: A class wants to publish a map of students' travel routes. Identify the risks, redesign the project to protect privacy, and explain how the safer version can still answer a useful geographic question.
- Evidence Based Map Communication: Create a thematic map from a small dataset, include appropriate map elements, and write a conclusion that separates what the data show from what you infer.
Evidence of Learning
- Knowledge: You can explain GIS, layers, coordinates, attributes, vector and raster data, remote sensing, spatial analysis, metadata, map scale, and projection at a Grades 7–8 level.
- Skills: You can formulate a geographic question, organize location data, choose suitable representations, read attribute information, compare layers, interpret patterns, and evaluate data quality.
- Products: You can produce a clear map, a simple attribute table, a short GIS investigation report, and a presentation or media product that communicates mapped evidence.
- Transfer: You can apply GIS thinking to unfamiliar questions in environmental science, communities, transport, safety, or public services and explain why particular layers or analyses are useful.
- Responsibility: You can recognize privacy, bias, uncertainty, and data-quality issues and make safer, fairer choices when collecting or sharing geographic information.
OERs on the Topic
The following open resources can help you explore GIS further. The English Wikipedia article provides an overview of geographic information systems. Wikimedia Commons hosts freely licensed GIS diagrams, maps, GPS images, and remote-sensing media. QGIS provides free and open-source GIS software and documentation, while public agencies and educational organizations provide geographic datasets and learning materials.
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