SpatioTemporal Asset Catalog

LINZ Historical Imagery Extension Specification

This is a work in progress and has not been reviewed everything is likely to change

LINZ is currently scanning 550,000 photo negatives from 7,300 aerial surveys flown between 1936 and 2008.

As of July 2020, more than 493,000 photos have been digitised and made available, free of charge, under the Creative Commons Attribution 4.0 International licence.

The survey metadata that is being converted to STAC can be viewed and downloaded from the LINZ Data Service.

For more details see The Crown Aerial Film Archive historical imagery scanning project.

STAC Collections

STAC Collection Fields

Field Name Type Description Internal Field Name
id string REQUIRED. Identifier for the Collection that is unique across the provider. N/A
title string REQUIRED. A short descriptive one-line title for the Collection. survey|alternate_survey_name

STAC Items

STAC Item Fields

Field Name Type Description Internal Field Name
id string REQUIRED. Provider identifier. The ID should be unique within the Collection that contains the Item. sufi
geometry GeoJSON Geometry Object | null REQUIRED. Defines the full footprint of the asset represented by this item, formatted according to RFC 7946, section 3.1. The footprint should be the default GeoJSON geometry, though additional geometries can be included. Coordinates are specified in Longitude/Latitude or Longitude/Latitude/Elevation based on WGS 84. shape
bbox [number] REQUIRED if geometry is not null. Bounding Box of the asset represented by this Item, formatted according to RFC 7946, section 5. shape

STAC Item Properties

Field Name Type Description Internal Field Name
datetime string|null REQUIRED. The searchable date and time of the assets, in UTC. It is formatted according to RFC 3339, section 5.6 and ISO 8601. null is allowed, but requires start_datetime and end_datetime from common metadata to be set. date

Common Metadata

Field Name Type Description Internal Field Name
platform string REQUIRED. Name of the platform to which the instrument is attached. N/A
instruments [string] Name of instrument or sensor used (e.g., MODIS, ASTER, OLI, Canon F-1). camera
mission string REQUIRED. Name of the mission for which data is collected. survey|alternate_survey_name

Projection Extension

Field Name Type Description Internal Field Name
proj:epsg integer|null REQUIRED. EPSG code of the data source. This is required by the STAC Projection Extension. Set to null if there is no suitable EPSG code. N/A
proj:centroid Centroid Object Coordinates representing the centroid of the Item (in lat/long). photocentre_lat|photocentre_lon

Electro-Optical Extension

Field Name Type Description Internal Field Name
eo:bands [Band Object] REQUIRED. The eo:bands array is used to describe the available spectral bands in an Asset. photo_type or image file metadata

Aerial Photography Extension

Field Name Type Description Internal Field Name
aerial-photo:run string REQUIRED. A straight line/pass of sequential imagery flown during a specific survey. run
aerial-photo:altitude integer Altitude in feet at which the plane was flying when the photo was taken. altitude
aerial-photo:scale integer Denominator of the distance on the ground relative to the distance on the physical film negative for a photo. scale
aerial-photo:sequence_number integer REQUIRED. Sequential order of photos taken during a run. photo_no
aerial-photo:anomalies string Comments about unusual things noticed in the image. image_anomalies

Camera Extension

Field Name Type Description Internal Field Name
camera:sequence_number integer Also referred to as veder; the sequential order of photos taken by an individual camera. camera_sequence_no
camera:nominal_focal_length integer Distance in mm from the camera lens centre to the film in the camera at which the image will have the least possible distortion. nominal_focal_length

Film Extension

Field Name Type Description Internal Field Name
film:id string REQUIRED. Identification number assigned by NZAM to each roll of film held in their storage. film
film:negative_sequence integer REQUIRED. Sequential order of each negative within a roll of film. film_sequence_no
film:physical_condition string Comments field about unusual film condition. physical_film_condition
film:physical_size string Physical size of the negatives on a roll of film. format

Scanning Extension

Field Name Type Description Internal Field Name
scan:is_original boolean Whether the scan is of an original negative (true) or a copy (false). source
scan:scanned string Date and time the corresponding data was scanned. For LINZ data, this will be the start datetime for the calendar year quarter in which the data was scanned. MUST be formatted according to RFC 3339, section 5.6. when_scanned