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Papakāinga and housing GIS

GIS cannot decide whether papakāinga should proceed, but it can make a complicated whenua question much easier to see. One map can bring together the land block, cadastral context, existing buildings, access, terrain, hazards, infrastructure and planning information so that questions become specific rather than abstract.

This page is about spatial investigation, not legal or planning advice.

Begin with the whenua question

Examples include:

  • Where are the flatter parts of the whenua?
  • Which areas are outside a modelled flood extent?
  • How far are possible building areas from existing access?
  • Where are water, wastewater or electricity constraints likely to matter?
  • Does the legal parcel pattern match the Māori land block being discussed?
  • What has already been built and how has the whenua changed over time?

Start with Māori land, Māori land blocks versus parcels and Whenua mapping.

Useful layers

QuestionUseful GIS layerWhat it contributes
What whenua are we looking at?Māori land block and cadastral parcelstwo different administrative/legal views of the land
What is already there?current aerial imagery, buildings, roadsvisible existing pattern
How steep is it?DEM, contours, derived slopeterrain screening
What hazards are mapped?council flood, coastal, landslide or other hazard layerspublished model context
How do we get there?roads, legal access, tracks, easements where availableaccess investigation
What services are nearby?water, wastewater, stormwater, electricity or transport layers where publishedinfrastructure context
What rules may matter?district or regional planning layersplanning context, not a substitute for reading the plan
What was there before?Retrolens and historic imageryland-use and access change over time

The LINZ Data Service provides national parcels, imagery, elevation, roads and other useful base information. Councils are usually the better source for local hazards, planning and infrastructure layers.

A useful QGIS project structure

Group the map by question rather than provider:

01 Whenua
02 Existing buildings and access
03 Terrain
04 Hazards
05 Infrastructure
06 Planning
07 Taiao
08 Historical imagery
09 Working analysis
10 Map outputs

This makes a hui map easier to understand than a layer panel organised as LINZ, Council, MfE, DOC and Other.

Derive slope

A DEM can be converted to slope in QGIS. Slope is useful for screening, but it is not a geotechnical assessment.

A simple workflow is:

  1. add the best available DEM for the area
  2. clip it to a reasonable buffer around the whenua
  3. calculate slope
  4. classify the slope into a few understandable bands
  5. compare those bands with existing buildings, access and hazards

The purpose is to identify questions worth investigating, not to declare a site buildable from a desktop map.

Compare candidate areas

Rather than creating a mysterious weighted suitability score, start with transparent overlays. A candidate area might be described as:

  • relatively gentle terrain
  • outside the current published flood layer
  • within a practical distance of existing access
  • close to existing services
  • not overlapping a feature that the project wants to avoid

Keep the individual layers visible so people can see why an area looks more or less practical.

Access can dominate the map

For some whenua, the critical GIS question is not the building platform but getting to it. Use Landlocked Māori land for a deeper access workflow. Distinguish visible tracks, road parcels, legal access and practical vehicle access rather than drawing one line called road.

Hazards need their model context

A flood polygon is not simply flooded or not flooded. Record the council, model or scenario, publication date and any return period or climate assumptions available. See Disaster and hazard mapping and Climate change.

Worked example

The Papakāinga investigation worked example uses synthetic candidate areas with public-style layers to show how to assemble a transparent screening map without pretending GIS has made the development decision. The layer register, candidate comparison and unresolved-question structure now live directly on that page rather than in a separate placeholder download.

Last reviewed: 3 September 2026