Geospatial - how people used location based information after the Christchurch earthquakes

About this virtual field trip

In this virtual field trip you'll:

• discover how GPS, surveying and geodetic information are used to measure land movement and locate places accurately
• discover how geospatial information supported decisions about rebuilding Christchurch, including new housing and building locations
• explore how geospatial information supported the response to and recovery from the Canterbury earthquakes
• explore how maps and location information support emergency planning, infrastructure and safer development
• learn how LiDAR and other technologies help measure changes to the landscape
• learn about topographic maps, map scales, contour lines, grid references and coordinates
• see how geospatial information helps identify earthquake, flooding and land stability risks.

Video series

Introduction to Geospatial

Main themes

• Introduction to the geospatial field trip to Christchurch.
• Technology, such as your phone, can be used to gather geospatial information in the field.

Key takeaways

• How geospatial information is helping with the rebuilding of Christchurch.
• Phones are a tool to be used to gather data.

Mapping land movement

Featured expert: Nick Donnelly, surveyor.

Main themes

• Finding a survey reference point using GPS.
• Using geospatial technology for accurate positioning and measurement of land movement.

Key takeaways

• Survey reference points are used to monitor how much New Zealand is moving each year, and after earthquakes.
• Survey reference points with GPS support more accurate measurement of locations and movement.

Land movement during the Canterbury earthquake of 2010

Featured expert: Nick Donnelly, surveyor.

Main themes

• About the Greendale Fault - a strike slip fault.
• Evidence of land movement caused by the September 2010 Canterbury earthquake.

Key takeaways

• GPS can more precisely measure land movement.
• Land movement below the surface can be greater than what is seen above the surface.

Locating earthquakes

Featured expert: Nick Donnelly, surveyor.

Main themes

• Using instruments to detect seismic waves.
• Understanding how seismic waves help locate earthquakes.
• Applying geospatial information to earthquake monitoring.

Key takeaways

• Earthquake monitoring relies on instruments that detect seismic waves.
• Geospatial information helps people understand the severity of an earthquake.

New housing subdivisions around Christchurch

Featured expert: Steve Bensberg, LINZ.

Main themes

• Using geospatial information to plan new subdivisions around Christchurch.
• Understanding topography when planning development.
• Using different types of information to identify suitable land uses, including safe places to build housing.

Key takeaways

• Geospatial information helps inform the safest place to build subdivisions.
• Geospatial information helps classify land into technical categories (TC), or rules for the use of land.

Nautical charts

Featured expert: Jen Ryan, nautical cartographer, LINZ.

Main themes

• How nautical charts are made and the information they show.
• Navigational aids for mariners.
• How Lyttelton Port kept operating after the Canterbury earthquakes.

Key takeaways

• Nautical charts support safe navigation for mariners.
• Nautical cartography brings together information needed for navigating the marine environment.

Tide gauges

Featured expert: Paula Gentle, Digital Delivery People, LINZ.

Main themes

• How tide gauges work at Lyttelton Port.
• Understanding mean sea level.
• Effects of the Canterbury earthquakes on tide measurements.

Key takeaways

• Tide gauges measure changes in sea level over time.
• Earthquakes and land movement can affect tide gauge measurements and their reference levels.

Surveying and geodetic survey marks

Featured expert: Paula Gentle, Digital Delivery People, LINZ.

Main themes

• How measurements are taken from geodetic survey marks.
• Measuring the height of points on the land.
• Why surveyors use two sets of measurements.

Key takeaways

• Geodetic survey marks provide fixed reference points for accurate surveying.
• Taking two sets of measurements helps support accurate height calculations.

Land elevation and contour lines

Featured expert: Paula Gentle, Digital Delivery People, LINZ.

Main themes

• Measuring elevation and height in the Port Hills of Christchurch.
• Reading and understanding contour lines.
• Effects of the Canterbury earthquakes on land elevation.

Key takeaways

• Contour lines show changes in elevation on a map.
• Earthquakes can change land height, making updated measurements important.

Digital maps and apps

Featured expert:  Richard Freeman, cartographer, LINZ.

Main themes

• How geospatial data supports everyday activities.
• How GPS works.
• Risks of relying on digital devices for navigation.

Key takeaways

• GPS allows digital devices to identify where you are.
• Digital navigation is useful, but it's important not to rely on it completely.

Use of topographic maps in Christchurch

Featured expert:  Richard Freeman, cartographer, LINZ.

Main themes

• How topographic maps supported the response to the Canterbury earthquakes.
• How topographic maps are used around Christchurch.

Key takeaways

• Topographic maps provide useful information about the landscape and terrain.
• Topographic maps helped people understand work that needed to be done after the earthquakes.

Map scales on 1:50,000 and 1:250,000 topographic maps

Featured expert:  Richard Freeman, cartographer, LINZ.

Main themes

• Understanding real world distances using a map.
• Comparing different scale topographic maps.

Key takeaways

• Different map scales provide different levels of detail.
• Map scale shows the relationship between distance on a map and distance on the ground.

Grid references and map orientation

Featured expert:  Richard Freeman, cartographer, LINZ.

Main themes

• How to orientate a map correctly.
• How to orientate a map with a compass.
• Using grid references to identify locations.
• Finding coordinates for a location.

Key takeaways

• Grid references and coordinates help pinpoint locations.
• A compass can be used to orientate a map accurately.

Topographic maps

Featured expert: Richard Freeman, cartographer, LINZ.

Main themes

• Features of a topographic map.
• How geodetic data is used to create topographic maps and map projections
• Latitude and longitude, land elevation, contour lines, legends, grid references and map orientation.

Key takeaway

• Topographic maps represent natural and human made features of the land.

Building consents for the  Christchurch rebuild

Featured expert: Steve Bensberg, LINZ.

Main themes

• The rebuilding of Christchurch after the Canterbury earthquakes.
• Building consents and identifying where new buildings are located.

Key takeaway

• Geospatial information supports demolition, planning and managing the Christchurch rebuild.
• Building locations need to be accurately recorded as the city changes.
• New building codes help make buildings safer.

Lifeline planning for natural disasters

Featured expert: Steve Bensberg, LINZ.

Main themes

• Planning for natural disasters.
• Protecting critical lifelines during emergencies.
• Using maps for emergency planning.

Key takeaway

• Lifeline infrastructure needs special planning for natural disasters.
• Maps help identify risks and support emergency planning.

Land level changes and flooding

Featured expert: Steve Bensberg, LINZ.

Main themes

• Land level changes following the Canterbury earthquakes.
• Flood risks and managing tidal flooding.
• Using LiDAR to measure land elevation.

Key takeaways

• LiDAR provides accurate information about land height.
• Geospatial information can help understand flood risk and assess management options.
• Low lying coastal areas can be particularly vulnerable to tidal flooding.

Testing land strength in Christchurch

Featured expert: Steve Bensberg, LINZ.

Main themes

• Testing land strength after the earthquakes.
• Liquefaction and how it affects decisions about land use.

Key takeaways

• Land testing helps identify the strength and condition of land.
• Testing provides information to support decisions on land use after earthquakes.

Summary of the LEARNZ Geospatial virtual field trip

Main theme

• Reflecting on how mapping and geospatial information were applied to the Christchurch rebuild.

Key takeaway

• Geospatial tools played an important role in responding to the Canterbury earthquakes and rebuilding Christchurch.

Key messages across the video series

1. Geospatial information helps us understand places and how they change

Maps, aerial imagery, surveying, GPS and other location information help us understand the land, identify features and measure changes caused by earthquakes.

2. Accurate location information supports earthquake response and recovery

After the Canterbury earthquakes, geospatial information helped people assess land movement, identify damaged areas and make decisions about rebuilding Christchurch.

3. Maps and location technologies support safer planning

Topographic maps, nautical charts, LiDAR an land information help people identify hazards, understand flood and land stability risks and decide where it is safer to build.

4. Geospatial information supports everyday decisions

Geospatial information is used for navigation, property development, infrastructure, emergency planning and managing the natural and built environments.

Overall LINZ connection

• LINZ provides and maintains topographic maps, nautical charts and geodetic information used for accurate positioning, surveying and navigation.
• LINZ geospatial information helps us measure and understand how the land changes following events such as earthquakes.
• LINZ data supports emergency response, recovery, rebuilding and planning for natural hazards.

More resources

Find resources related to field trips and location information:

Resources for LEARNZ virtual field trips