git:20261008.c9d8874 to git:20261011.1a28fac

20 added, 9 removed. Audit A to A.

---

name: nz-stac

- description: "Find LINZ elevation and aerial imagery collections and COG tiles from public NZ STAC catalogues. Use for DEM/DSM, RGB/infrared footprints, bbox tile searches and elevation point sampling guidance."

+ description: "Find LINZ elevation, coastal LiDAR, and aerial imagery collections and COG tiles from public NZ STAC catalogues. Use for DEM/DSM, coastal elevation footprints, RGB/infrared footprints, bbox tile searches and elevation point sampling guidance."

license: MIT

compatibility: "Requires Python 3.10+ and network access for live data"

metadata:

thecolab.category: "geospatial"

thecolab.source_owner: "Toitū Te Whenua Land Information New Zealand"

thecolab.source_type: "official"

thecolab.auth: "none"

thecolab.access_mode: "public-STAC-HTTPS"

thecolab.data_class: "public"

thecolab.writes: "false"

thecolab.browser: "false"

thecolab.risk: "low"

thecolab.cache_ttl: "none"

thecolab.schema_version: "1"

thecolab.skill_type: "public-api"

thecolab.pack: "nz-public-data"

thecolab.source_url: "https://nz-elevation.s3.ap-southeast-2.amazonaws.com/catalog.json"

- thecolab.allowed_domains: "nz-elevation.s3.ap-southeast-2.amazonaws.com,nz-imagery.s3.ap-southeast-2.amazonaws.com"

- thecolab.last_verified: "2026-10-08"

+ thecolab.allowed_domains: "nz-elevation.s3.ap-southeast-2.amazonaws.com,nz-imagery.s3.ap-southeast-2.amazonaws.com,nz-coastal.s3.ap-southeast-2.amazonaws.com"

+ thecolab.last_verified: "2026-10-12"

thecolab.health: "healthy"

thecolab.maintainer: "@adam91holt"

---

# NZ STAC

Find datasets and Cloud Optimised GeoTIFF (COG) tile URLs in LINZ's public

- `nz-elevation` and `nz-imagery` AWS buckets, hosted in `ap-southeast-2`.

- Python 3.10+, stdlib only; no AWS credentials, boto3, or LINZ Data Service key.

+ `nz-elevation`, `nz-imagery`, and `nz-coastal` AWS buckets, hosted in

+ `ap-southeast-2`. Python 3.10+, stdlib only; no AWS credentials, boto3, or

+ LINZ Data Service key. Coastal commands return collection metadata and COG

+ hrefs only. They do not download DEM or DSM rasters.

## Workflow

1. Run `collections` with the bucket kind and optional region. Copy the returned

`collection` selector (kind plus published path), or use its HTTPS

`collection.json` URL. `info` returns the upstream STAC id and full metadata.

2. Check capture interval, product and resolution with `info`. DEM represents

terrain; DSM includes surface features. Use the source capture dates for

freshness, rather than its processing/update date.

3. Use a small WGS84 bbox to find tiles. `--format geojson` emits a

FeatureCollection of the actual STAC footprints. Assets are public HTTPS COG

URLs. The helper fetches bounded JSON metadata only, never raster files.

- 4. For a terrain point, use a DEM collection with `point`. It returns

+ 4. For a terrain point, use an elevation DEM collection with `point`. Coastal

+ collections are not accepted there. It returns

`sampling_status=sampling_required`, `elevation=null`, the tile URL and a

`gdallocationinfo` one-liner. Run that command with GDAL installed to sample

remotely by HTTP range reads. Check nodata and the source vertical datum.

The stdlib helper does not decode compressed GeoTIFFs or report an invented

elevation. A tile footprint may contain nodata.

## Commands

Run from the repository root, or use an absolute path to `scripts/cli.py`.

```bash

python3 skills/nz-stac/scripts/cli.py collections --kind elevation --region auckland --json

python3 skills/nz-stac/scripts/cli.py collections --kind imagery --region auckland --json

+ python3 skills/nz-stac/scripts/cli.py collections --kind coastal --region auckland --limit 20 --json

+ python3 skills/nz-stac/scripts/cli.py info coastal:auckland/mangawhai-to-snells_2025/dem_1m/2193 --json

+ python3 skills/nz-stac/scripts/cli.py tiles coastal:auckland/mangawhai-to-snells_2025/dem_1m/2193 --bbox 174.59,-36.01,174.60,-36.00 --limit 5 --json

python3 skills/nz-stac/scripts/cli.py info elevation:auckland/auckland-part-1_2024/dem_1m/2193 --json

python3 skills/nz-stac/scripts/cli.py tiles elevation:auckland/auckland-part-1_2024/dsm_1m/2193 --bbox 174.715,-36.905,174.725,-36.895 --json

python3 skills/nz-stac/scripts/cli.py tiles elevation:auckland/auckland-north_2016-2018/dem_1m/2193 --bbox 174.715,-36.905,174.725,-36.895 --format geojson

python3 skills/nz-stac/scripts/cli.py tiles imagery:auckland/auckland_2024_0.075m/rgb/2193 --bbox 174.715,-36.905,174.725,-36.895 --format geojson

python3 skills/nz-stac/scripts/cli.py tiles imagery:auckland/auckland_2024_0.075m/rgbnir/2193 --bbox 174.715,-36.905,174.725,-36.895 --limit 5 --json

python3 skills/nz-stac/scripts/cli.py point --lon 174.72 --lat -36.9 --collection elevation:auckland/auckland-part-1_2024/dem_1m/2193 --json

```

Every data command supports `--json`; `tiles` and `point` also support

`--format geojson`. Human output is the default.

## Bounds and interpretation

- `--bbox` is `minLon,minLat,maxLon,maxLat`. Longitude comes first. Tile search

supports mainland NZ Topo50 tile names in EPSG:2193; unsupported grids fail

clearly. Chatham Islands need a different CRS.

- Collections default to 100 records, capped at 200 per request. Use `--offset`

and `--limit` for another slice. `matched` is the catalogue count after region

- filtering. Listings derive year, resolution and product from published names

- and paths; licence is null until `info` or tile metadata supplies it.

+ filtering. The coastal catalogue has more collections than the default page,

+ so an unfiltered coastal listing is truncated. Listings derive year, resolution

+ and product from published names and paths; licence is null until `info` or

+ tile metadata supplies it. Hillshade paths stay `unknown` rather than DEM or DSM.

+ - `point` accepts elevation DEM and DSM collections only. A coastal selector is

+ rejected. Use `tiles` for coastal COG hrefs. OpenAerialMap and Copernicus GFM

+ are different publishers and are not kinds of this skill.

- Tile results default to 20, capped at 50. At most 100 nearby item JSON files

are candidates; a larger bbox fails with a request to narrow it. `truncated`

means at least one additional matching footprint exists. Results include

`candidates` and `items_inspected`; there is no unbounded item crawl.

- JSON envelopes and records carry `source_url`, `publisher`, `licence`,

`retrieved_at` (UTC) and `latest_data` (capture end, or the catalogue title's

stated year range). Unknown metadata stays null.

- `point` returns all discovered touching tiles up to four, with an explicit

truncation flag. `no_tile` means no intersecting tile in that collection.

It does not mean the location has no elevation in other collections.

Read [references/source-notes.md](references/source-notes.md) for the static

STAC schema, tile-grid method, exact Auckland selectors and source limits.

Verify the skill with `scripts/test_contract.py` (deterministic fixtures) and

- `scripts/smoke_test.py` (bounded live Auckland probes and one 16-byte COG range).

+ `scripts/smoke_test.py` (bounded live Auckland probes and 16-byte COG ranges).