Items & Assets

Items

In the Planet API, an item is an entry in our catalog, and generally represents a single logical observation (or scene) captured by a satellite. Each item is defined by an item_type, which represents the class of spacecraft and/or processing level of the item. Assets (or products, such as visual or analytic) can be derived from the item's source data.

All items have a standard (or shared) set of properties. A few examples of shared properties are:

  • acquired - Date-time at which the imagery was captured.
  • geometry - An item's physical footprint, described as GeoJSON.
  • published - Date-time at which this item was added to the API.

Items also have additional properties that are specific to the item_type of the item. All items of a given item_type share all properties with one another. Whenever possible, properties that are identically named between different item_types will have the same schema and semantics. For example, acquired is an RFC-3339 timestamp in all items where it appears, enabling meaningful comparisons across item_types.

Planet operates the PlanetScope (PS) and RapidEye (RE) Earth-imaging constellations. Imagery is collected and processed in a variety of formats to serve different use cases, be it mapping, deep learning, disaster response, precision agriculture, or simple temporal image analytics to create rich information products.

PlanetScope satellite imagery is captured as a continuous strip of single frame images known as “scenes.” Scenes may be acquired as a single RGB (red, green, blue) frame or a split-frame with a RGB half and a NIR (near-infrared) half depending on the capability of the satellite.

Planet offers three product lines for PlanetScope imagery: a Basic Scene product, an Ortho Scene product, and an Ortho Tile product. The Basic Scene product is a scaled Top of Atmosphere Radiance (at sensor) and sensor-corrected product. The Basic Scene product is designed for users with advanced image processing and geometric correction capabilities. The product is not orthorectified or corrected for terrain distortions.Ortho Scenes represent the single-frame image captures as acquired by a PlanetScope satellite with additional post processing applied. Ortho Tiles are multiple orthorectified scenes in a single strip that have been merged and then divided according to a defined grid.

Item Types

An item_type represents the class of spacecraft and/or processing level of an item. All items have an associated item_type. Each item_type has a specific list of assets_types that can be derived from the item's source data.

All items within an item_type group will have identical schemas with no nullified or optional properties. Items across item_types may also share identical properties, and generally have the same schema and semantics to facilitating cross item_type searching using shared properties. As an example, both REOrthoTile and PSOrthoTile items have acquired, published, and black_fill properties. It can be assumed that these properties have the same meaning across both item_types.

Whenever possible, item data is sliced in a similar manner across item_types. For example, PSOrthoTile items are geometrically segmented along the RapidEye Level 3A grid.

PlanetScope items are exposed under multiple item_types

Individual PlanetScope scenes are exposed under 2 different item_types. All PlanetScope items can be found under both PSScene3Band and PSScene4Band, each exposing different assets_types that can be generated.

Available Item Types Description
PSScene3Band PlanetScope 3 band scenes (red, green, blue) captured by the Dove satellite constellation
PSScene4Band PlanetScope 4 band scenes (red, green, blue, near-infrared) captured by the Dove satellite constellation
PSOrthoTile PlanetScope ortho tiles captured by the Dove satellite constellation
REOrthoTile RapidEye OrthoTiles captured by the RapidEye satellite constellation
REScene Unorthorectified strips captured by the RapidEye satellite constellation
SkySatScene SkySat Scenes captured by the SkySat satellite constellation
SkySatCollect Orthorectified scene composite of a SkySat collection
SkySatVideo Full motion videos collected by a single camera from any of the active SkySats
Landsat8L1G Landsat8 Scenes provided by USGS Landsat8 satellite
Sentinel2L1C Copernicus Sentinel-2 Scenes provided by ESA Sentinel-2 satellite

Assets

An asset describes a product that can be derived from an item's source data, and can be used for various analytic, visual or other purposes. Assets are generally either image data or metadata. items have many assets available for production and download, each a different representation of the same item using different processing steps. As an example, an item may have a visual or an analytic asset. The visual asset is intended for display, while the analytic can be used for further processing.

For a complete listing of asset_types available for each item_type, checkout the item type specifics in this section.

Item Publishing Lifecycle

An item's publishing stage will help you understand when the right time is to download an item, based on whether your pipeline needs to optimize for data latency or data accuracy.

Publishing stage is only available for PlanetScope and SkySat items: PSScene3Band, PSScene4Band, PSOrthoTile, SkySatScene, SkySatCollect, SkySatVideo. It supports the following values, availablilty and prevalence of each varying by item type:

  • preview: Lowest latency, lowest fidelity. Data is unrectified; metadata changes are expected upon subsequent republishing.
  • standard: Standard latency, standard fidelity. Data is stable and rectified, but subject to minimal metadata changes upon republishing.
  • finalized: Highest latency, highest fidelity. Data is stable and rectified, no additional metadata changes are expected (barring any bug fixes or new quality improvements)

This field will be available for all PlanetScope and SkySat items published after June 19, 2020. By mid-July, these fields will be backfilled for the full archive.

Preview Stage

Applicable only to unrectifiable, open water or cloud PSScene3Band items (less than 5% of all PSScene3Band items) and all SkySatScene items.

  • "Preview" PSScene3Band items typically published about an hour before they will be republished as "standard" (if they are rectifiable).
  • "Preview" SkySatScene items (L1A assets) are typically published two hours before they will be rectified and republished as "finalized".

Upon republishing to "standard" or "finalized", significant metadata changes are expected. If the data is unrectifiable, it will remain in "preview" stage.

Standard Stage

Applicable to all PSScene4Band, PSOrthoTile, and rectifiable PSScene3Band items. With the exception of unrectifiable, open water/cloudy PSScene3Band imagery, all of PlanetScope publishing will start in the "standard" stage. Note: this stage is not used for SkySat publishing.

All "Standard" PlanetScope items will be republished to a "finalized" stage and may be subject to minimal change upon republishing as more scenes within a strip are published.

Finalized Stage

Applicable to all PSScene4Band, PSOrthoTile, SkySatCollect, SkySatVideo, and rectifiable PSScene3Band and SkySatScene items. While no further republishing or metadata changes are expected as part of standard publishing for "finalized" items, Planet's catalog is dynamic and we will republish items as bug fixes, new metadata fields, new asset types, and broader quality improvements are released. You can read more on our UpdateFilter feature to learn about ways we support redownloading to filter on these enhancements.

  • For PSScene3Band and PSScene4Band items, "finalized" data will be available approximately 12-24 hours after an item reaches "standard" stage.
  • For PSOrthoTile items, "finalized" data will be available approximately 48 hours after an item reaches "standard" stage. If your workflow leverages PSOrthoTile data products, we recommend downloading PSOrthoTiles only when they are in a "finalized" stage to ensure that the geometry is complete (i.e. all adjacent scenes are available to produce a complete orthotile)
  • For SkySatScene items, "finalized" data wil be available approximately 2 hours after an item is published as "preview"
  • All SkySatCollect and SkySatVideo items will start and end in "finalized" stage