During a wildfire season, a map on your phone can show where fires are burning, which way the smoke is blowing and which roads are closed, updated within hours. That map exists because of geospatial technology: tools that collect, store, analyse and display information tied to a place on Earth. Your phone's map app, a farmer's self-steering tractor and a satellite watching sea ice in the Arctic all use it. In this lesson you will see how the three big tools fit together and why the skills behind them lead to so many jobs.
GIS: stacking layers of data
A geographic information system (GIS) is computer software that stores data as layers, each one matched to the same locations: roads, rivers, land use, buildings, population, soil and so on. Every feature can carry attribute data (a road's name and speed limit, a census area's population). The power of GIS is overlay: switching layers on and off and combining them to answer questions no single map can, such as "Which homes are inside the flood zone?" or "Which neighbourhoods are more than 1 km from a grocery store?" Be careful with what an overlay shows: two patterns that line up on a map are related (a correlation), but that alone does not prove one causes the other, so look for evidence of a cause. Cities use GIS to plan bus routes, emergency services use it to dispatch ambulances, and conservation authorities use it to map floodplains.
GPS: finding an exact position
The Global Positioning System (GPS) is a network of about 30 satellites run by the United States. Each satellite sends out a signal saying where it is and the exact time. A receiver, such as your phone, compares the arrival times of signals from at least four satellites to calculate its latitude, longitude and elevation. GPS is one of several global navigation satellite systems (GNSS): Europe runs Galileo, Russia GLONASS and China BeiDou, and most phones use several at once. A phone is usually accurate to within a few metres outdoors; professional survey equipment can reach centimetres. GPS steers tractors to plant straight rows, guides bulldozers on construction sites, helps search-and-rescue teams, and lets wildlife biologists track caribou with GPS collars.
Remote sensing: seeing from above
Remote sensing means collecting information about Earth from a distance, usually from satellites, aircraft or drones. Passive sensors record natural energy: sunlight reflected from the surface, including infrared light our eyes cannot see (healthy plants reflect a lot of near-infrared, so it reveals crop health and forest damage), and heat given off by the surface (thermal infrared). Active sensors send out their own signal and measure what bounces back. Canada is a world leader in radar satellites: RADARSAT-1 (launched 1995), RADARSAT-2 (2007) and the three-satellite RADARSAT Constellation Mission (2019). Radar sees through cloud and works day or night, which matters in a cloudy, dark northern country. It is used to map Arctic sea ice for ships, track floods, spot oil spills and monitor crops. Satellites also detect the heat of wildfires: Natural Resources Canada's Canadian Wildland Fire Information System maps satellite "hotspots" so fire crews and communities can respond quickly.
- Google Earth: free satellite and 3-D views; its historical imagery lets you compare a place across years (for example, a city spreading onto farmland).
- Statistics Canada's Census Program Data Viewer: maps and compares census data such as population, age and language for places across Canada.
- Natural Resources Canada topographic maps and the Canadian Wildland Fire Information System: free national maps and live fire data.
- Ontario GeoHub (run by Geospatial Ontario, formerly Land Information Ontario): free provincial data such as roads, wetlands, parks and watersheds.
- Native Land Digital: a starting point for Indigenous territories, languages and treaties, with its own caveat that it is not an official or legal map.
Skills and careers that use geography
| Career | How it uses geography |
|---|---|
| GIS technician or analyst | Builds and analyses map layers for cities, utilities, governments and companies |
| Land surveyor | Measures and marks property lines and construction sites with GNSS and survey instruments. In Ontario it is a regulated profession: Ontario Land Surveyors are licensed by their association under the Surveyors Act |
| Urban or land-use planner | Decides where homes, parks, roads and businesses should go, using maps, census data and public input |
| Drone pilot | Captures aerial photos and maps for farming, construction, mining and emergencies; needs a Transport Canada drone pilot certificate to fly drones that weigh 250 g or more |
| Forestry technician | Maps forest stands, plans harvests and replanting, and monitors fire and insect damage |
| Conservation officer | Enforces fish, wildlife and environmental laws across large areas using maps and GPS |
| Construction trades (e.g. carpenter, heavy equipment operator) | Read site plans, elevations and grade stakes; many machines now use GPS guidance to dig to the right depth |
| Remote-sensing or environmental scientist | Interprets satellite and drone images to track floods, sea ice, crops and climate change |
You will meet these tools again and again: satellite images of glaciers and wildfires in Unit 2, maps of mines and energy projects in Unit 3, census maps of population and immigration in Unit 4, and land-use maps for planning a liveable community in Unit 5.