Planet STAC Extension

• Title: Planet Labs
• Identifier: https://planetlabs.github.io/stac-extension/{{version}}/schema.json (see the releases page for a list of published versions)
• Field Name Prefix: pl
• Scope: Item
• Extension Maturity Classification: Proposal
• Owner: @cholmes @tschaub @m-mohr

This document describes the Planet Labs Extension to the SpatioTemporal Asset Catalog (STAC) specification. The extension defines fields specific to the products offered by Planet Labs.

The fields defined here are mostly mapped directly from the Item Properties defined in the Planet API. If possible the fields are mapped to commonly used fields in STAC, including a variety of extensions (e.g. eo, view). See Field mapping and scope for a table that maps between Planet Item Properties and STAC fields. Sometimes fields don't map 1:1 and need a slight conversion, which will be mentioned in the description for each field here. It also gives an overview over the fields that are available for the individual item types.

The following item types are covered by this extension:

• PlanetScope:
  • PSOrthoTile
  • PSScene
• RapidEye:
  • REOrthoTile
  • REScene
• SkySat:
  • SkySatCollect
  • SkySatScene
  • SkySatVideo
• Landsat
  • Landsat8L1G
• MODIS
  • MOD09GA, MYD09GA, MOD09GQ, MYD09GQ
• Sentinel
  • Sentinel1
  • Sentinel2L1C

The deprecated item types PSScene3Band and PSScene4Band are not supported and will not be validated.

Important links for this extension:

• Examples:
  • Browse in STAC Browser
  • PlanetScope:
    • PSScene Item
    • PSOrthoTile Item
  • RapidEye:
    • REOrthoTile Item
    • REScene Item
  • SkySat:
    • SkySatCollect Item
    • SkySatScene Item
  • Others:
    • Landsat8L1G Item
    • MOD09GA Item
    • MOD09GQ Item
    • MYD09GA Item
    • MYD09GQ Item
    • Sentinel1 Item
    • Sentinel2L1C Item
• JSON Schema

Item Properties Fields

The fields in the tables below can be used in these parts of STAC documents:

• Catalogs
• Collections
• Item Properties (including Summaries in Collections)
• Assets (for both Collections and Items, including Item Asset Definitions in Collections)
• Links

Planet-specific

Field Name	Type	Description
pl:black_fill	number	The percentage of the item containing black fill in the range 0 - 100 (inclusive).
pl:clear_percent	number	Percent of clear values in dataset. Percentages must be provided in the range 0 - 100 (inclusive).
pl:grid_cell	string	The grid cell identifier of the gridded item.
pl:ground_control	boolean	Positional accuracy of the item. If the item has uncertain positional accuracy, this value will be false.
pl:ground_control_ratio	number	Ratio of individual scenes that are successfully rectified, in the range 0 - 1 (inclusive). Only applies to SkySatCollect.
pl:item_type	string	REQUIRED. Name of the item type. Allowed values: see below
pl:pixel_resolution	number	The spatial resolution, in meters. (This is meant to be deprecated in favor of spatial_resolution.)
pl:publishing_stage	string	Stage of publishing for an item. Allowed values: preview, standard, finalized.
pl:quality_category	string	Metric for image quality. Allowed values: standard, test.
pl:strip_id	string	The unique identifier of the image stripe that the item came from.

Additional REQUIRED fields per pl:item_type:

Field Name	PSOrthoTile	PSScene	REOrthoTile	REScene	SkySatCollect	SkySatScene	SkySatVideo	Landsat8L1G	M(O/Y)D09G(A/Q)	Sentinel1	Sentinel2L1C
pl:black_fill	✓		✓	✓					✓	✓	✓
pl:clear_percent	✓	✓			✓	✓
pl:grid_cell	✓		✓
pl:ground_control	✓	✓	✓			✓
pl:ground_control_ratio					✓
pl:pixel_resolution	✓	✓	✓		✓	✓		✓	✓		✓
pl:publishing_stage	✓	✓			✓	✓	✓
pl:quality_category	✓	✓			✓	✓	✓	✓	✓	✓	✓
pl:strip_id	✓	✓	✓	✓	✓	✓	✓

pl:item_type

The following values exist for the Planet Labs satellites:

• PlanetScope:
  • PSOrthoTile
  • PSScene
• RapidEye:
  • REOrthoTile
  • REScene
• SkySat:
  • SkySatCollect
  • SkySatScene
  • SkySatVideo

The following item types don't come from Planet satellites, but have some support in Planet APIs:

• Landsat8L1G
• MOD09GA, MYD09GA, MOD09GQ, MYD09GQ
• Sentinel1
• Sentinel2L1C

Other Extensions and Specifications

This extension uses and requires additional fields from other specifications/extensions.

The following specifications are relevant here:

• STAC Common Metadata
• STAC EO Extension (v1.1.0 or later)
• STAC Viewing Angles Extension (v1.0.0 or later)

Field Name	Type	Description
constellation	string	REQUIRED. As defined in common metadata, but restricted to one of the constellations below.
platform	string	REQUIRED. Globally unique satellite identifier as defined in common metadata, but restricted to the patterns listed below.
instruments	[string]	The instrument identifier as defined in common metadata, but restricted to those listed below.
datetime	string	REQUIRED. The acquisition time As defined in common metadata and STAC.
gsd	number	Ground sample distance as defined in common metadata.
eo:cloud_cover	number	Cloud cover as defined in the EO extension.
eo:snow_cover	number	Snow/ice cover as defined in the EO extension.
view:azimuth	number	Viewing azimuth angle (0 - 360) as defined in the Viewing Angles extension.
view:off_nadir	number	REQUIRED. The satellite's across-track, off-nadir viewing angle (0 - 90).
view:sun_azimuth	number	REQUIRED. Sun azimuth angle as defined in the Viewing Angles extension (0 - 360).
view:sun_elevation	number	REQUIRED. Sun elevation angle as defined in the Viewing Angles extension (-90 - 90).

Additional REQUIRED fields per pl:item_type:

Field Name	PSOrthoTile	PSScene	REOrthoTile	REScene	SkySatCollect	SkySatScene	SkySatVideo	Landsat8L1G	M(O/Y)D09G(A/Q)	Sentinel1	Sentinel2L1C
instruments	✓	✓						✓	✓		✓
gsd	✓	✓	✓	✓	✓	✓		✓	✓	✓	✓
eo:cloud_cover	✓	✓	✓	✓	✓	✓		✓	✓		✓
eo:snow_cover		✓			✓	✓
view:azimuth	✓	✓			✓	✓	✓
view:sun_azimuth	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓
view:sun_elevation	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓
sar:frequency_band										✓
sar:instrument_mode										✓
sar:observation_direction										✓
sar:polarizations										✓
sar:product_type										✓

constellation

The following values exist for the Planet Labs satellites:

• PlanetScope: planetscope
• RapidEye: rapideye
• SkySat: skysat

For non Planet Satellites:

• Landsat8/MODIS: usgs
• Sentinel: esa

platform

The following patterns are allowed for the Planet Labs satellites:

• PlanetScope: [0-9a-f]{2,} (e.g. 0c08, 227c, etc.)
• RapidEye: RapidEye-\d+ (e.g. RapidEye-1, RapidEye-2, etc.)
• SkySat: SS(C\\d+|01|02) (e.g. SS01, SSC1, SSC19, etc.)

For non Planet Satellites:

• Landsat8: Landsat8
• MODIS: Terra or Aqua
• Sentinel: Sentinel\w+

instruments

The following values exist for the Planet Labs satellites:

• PlanetScope: PS2 (Dove Classic), PS2.SD (Dove-R), PSB.SD (SuperDove)
• RapidEye: n/a
• SkySat: n/a

For non Planet Satellites:

• Landsat8: OLI_TIRS
• MODIS: MODIS
• Sentinel1: n/a
• Sentinel2: MSI

Please note that the instruments field is always specified as an array.

view:off_nadir

This field is basically the view_angle field in the Planet API. The values are equal for SkySat and Planetscope, but for RapidEye they can also be negative (positive numbers denote east, negative numbers denote west). So the view_angle as defined by the Planet API maps 1:1 to view:off_nadir, but for RapidEye you have to use the absolute value of view_angle.

Asset Fields

Planet-specific

The fields in the tables below can be used in these parts of STAC documents:

• Catalogs
• Collections
• Item Properties (incl. Summaries in Collections)
• Assets (for both Collections and Items, incl. Item Asset Definitions in Collections)
• Links

Field Name	Type	Description
pl:asset_type	string	The type of asset.
pl:bundle_type	string	The type of bundle the asset belongs to.

pl:asset_type

These asset types are specific to Planet and may lead to additional requirements in the future.

The allowed asset types can be found here per item type:

• PlanetScope:
  • PSOrthoTile
  • PSScene
• RapidEye:
  • REOrthoTile
  • REScene
• SkySat:
  • SkySatCollect
  • SkySatScene
  • SkySatVideo
• Landsat, Sentinel, MODIS
  • These asset types aren't documented as much on the Planet side, but can be explored here or in the schema

The JSON Schema also provides a full list of all allowed values.

Other Extensions and Specifications

Additionally, this extension uses and partially requires additional fields from other specifications/ extensions. The following specifications are relevant here:

• STAC Common Metadata
• STAC Projection Extension (v1.1.0 or later)
• STAC Raster Extension (v1.0.0 or later)
• STAC Timestamps Extension (v1.1.0 or later)

For Sentinel1

• STAC SAR Extension (v1.0.0 or later)

Field Name	Type	Description
published	string	REQUIRED. Time of data publication as defined in the STAC Timestamps Extension.
updated	string	REQUIRED. Time of most recent data update as defined in STAC Common Metadata.
proj:espg	integer	The EPSG code as defined in the Projection extension.
proj:shape	[integer]	The number of rows and cols in the image as defined in the Projection extension.
raster:bands	[Raster Band Object]	The bands of the file with a spatial_resolution.

These fields should only be provided for actual data files (e.g. COG), not for metadata (e.g. XML). Currently, the JSON Schema does not fully validate these fields.

The fields defined in the Projection extension can either be used at the Asset-level or go into the Item Properties. To avoid ambiguities it is recommended to have them at the Asset-level, but both is allowed.

Additional REQUIRED fields per pl:item_type:

Field Name	PSOrthoTile	PSScene	REOrthoTile	REScene	SkySatCollect	SkySatScene	SkySatVideo	Landsat8L1G	M(O/Y)D09G(A/Q)	Sentinel1	Sentinel2L1C
proj:epsg	✓		✓					✓		✓	✓
proj.shape	✓	✓	✓	✓				✓		✓	✓
raster:bands[*].spatial_resolution	✓	✓	✓		✓	✓		✓			✓

Note: These requirements are not enforced in the JSON Schema yet.

Providers

For the providers field in a STAC Collection (or in the STAC Item Properties), it is recommended to provide the following details for Planet:

• Name: Planet Labs PBC
• Roles: at least producer and licensor