STAC Asset Reader Parameters

Connection

Select either a predefined STAC API or the type of STAC object that URL will point to.

The table below lists predefined STAC APIs and their root endpoints. Selecting one of these STAC APIs means that you do not need to pass in a URL.

Copernicus Sentinel Hub

  • Under Use Authentication, a Copernicus Sentinel Hub web connection must be specified to access a Copernicus Sentinel Hub dataset.
  • Accessing a Copernicus Sentinel Hub dataset requires both a temporal and spatial filter.
  • Copernicus Sentinel Hub Authentication guide

Microsoft Planetary Computer (default)

Sentinel Hub

  • Under Use Authentication, a Sentinel Hub web connection must be specified to access a Sentinel Hub dataset.
  • Accessing a Sentinel Hub dataset requires both a temporal and spatial filter.
  • Sentinel Hub Authentication guide

WeatherLayers

  • Under Use Authentication, a WeatherLayers web connection must be specified to access a WeatherLayers dataset.
  • Accessing a WeatherLayers dataset requires a temporal filter.

  • In the WeatherLayers web connection, the Origin value must be specified as an Allowed Origin in the WeatherLayers web interface. By default, the Origin value is https://safe.com. Allowed Origins can be modified in the WeatherLayers project settings.

  • WeatherLayers site

Rather than a predefined STAC API, you can also select one of: API, Catalog, Collection, FeatureCollection, or Item. This represents the type of STAC object that URL points to.

Note  When requesting a STAC API, the root Catalog will be returned.

Specify the STAC API, Catalog, Collection, Item, or FeatureCollection to read.

Note  This option is not available if STAC Type is set to Copernicus Sentinel Hub, Microsoft Planetary Computer, Sentinel Hub, or WeatherLayers.

Use Authentication

Specify the web connection required for browsing the specified data. Only one web connection is allowed.

Note  To add a web connection, select Add Web Connection from the dropdown menu. You can also add web connections from the Workbench Tools menu: select FME Options > Web Connections, then click the + button.

Specify or add a Copernicus Sentinel Hub web connection to access Copernicus Sentinel Hub datasets.

Specify or add a Sentinel Hub web connection to access Sentinel Hub datasets.

Specify or add a WeatherLayers web connection to access WeatherLayers datasets.

Filter

If a child Catalog or Collection is available, you can select which to fetch by clicking the browse [...] button to view any Catalogs or Collections contained by the STAC object passed into the URL.

Note  This option is not available if STAC Type is set to Item or FeatureCollection.
Note  The order of Catalogs and Collections listed in the web select is based on its order in the links field of its parent, and is therefore not guaranteed to be in alphabetical order.
Note  This option is not available if STAC Type is set to Item.

After specifying the STAC dataset, apply a date filter to narrow down results. Note that filters are most effective when a STAC API is passed in. Using a filter on a STAC Catalog, Collection, or FeatureCollection may result in significant wait times.

By default, this option is turned off.

Date Filter Type

Choose between Latest (default) and Date Range.

  • Start Date: If the Date Filter Type is Date Range, select from the calendar, or enter a DateTime in the format YYYY-MM-DD 00:00:00.
  • End Date: If the Date Filter Type is Date Range, select from the calendar, or enter a DateTime in the format YYYY-MM-DD 00:00:00.
Note  This option is not available if STAC Type is set to Item.

After specifying the STAC dataset, apply a spatial filter to narrow down results. Coordinates are expected to be in WGS84.

Minimum Longitude

The minimum longitude coordinate for the dataset bounds.

Minimum Latitude

The minimum latitude coordinate for the dataset bounds.

Maximum Longitude

The maximum longitude coordinate for the dataset bounds.

Maximum Latitude

The maximum longitude coordinate for the dataset bounds.
Note  
  • Filters are most effective when a STAC API is passed in. Using a filter on a STAC Catalog, Collection, or FeatureCollection may result in significant wait times.
  • Spatial filters are handled differently between a STAC API and non-API STAC object. When applied with a STAC API, spatial filtering is done by checking that each Item geometry intersects with the user-specified bounding box. When applied with a STAC Catalog, Collection, or FeatureCollection, spatial filtering is done by checking that each Item bounding box overlaps with the user-specified bounding box.

By default, this option is disabled.

Note  This option is not available if STAC Type is set to Item.

Select the STAC Item by clicking the browse [...] button to open the Select File From dialog.

The list of STAC Items available for reading is determined by the dataset selected and the filters applied.

Note  If STAC Type is set to API and the selected Catalog/Collection for Catalog or Collection is missing the type field in its metadata, a default type of Collection will be assumed. This may lead to incorrect Items being listed. This can be resolved by using a direct link to the desired Catalog/Collection and setting STAC Type to Catalog or Collection.
Note  The order of Items listed in the web select is based on its order in the links field of its parent, and is therefore not guaranteed to be in alphabetical order.

Dataset

Select the STAC Asset(s) to read by clicking the browse [...] button. Note that this list refers to the list of possible feature types.

Note  Although most STAC Assets will result in a single feature type, it is possible that a STAC Asset may involve multiple feature types and will be listed as such. The list available for reading is determined by the dataset selected.

The reader currently supports reading raster assets, (Geo)JSON assets, GeoPackages, and text files. Here is a list of supported MIME types:

  • application/geo+json
  • application/geopackage+sqlite3
  • application/json
  • application/xml
  • image/jpeg
  • image/jp2
  • image/png
  • image/tiff; application=geotiff
  • image/tiff; application=geotiff; profile=cloud-optimized
  • text/plain
  • text/xml

Use Asset Authentication

Specify the web connection required for reading the STAC Assets. The STAC Asset reader only supports authentication of assets stored in S3.

  • Web Connection – Specify or add an Amazon S3 Compatible Storage or Amazon Web Service web connection to access assets stored in S3.

Schema Attributes

Use this parameter to expose Format Attributes in FME Workbench when you create a workspace:

  • In a dynamic scenario, it means these attributes can be passed to the output dataset at runtime.
  • In a non-dynamic scenario, this parameter allows you to expose additional attributes on multiple feature types. Click the browse button to view the available format attributes (which are different for each format) for the reader.
 
 

Use Search Envelope

A search envelope (also known as a bounding box) is a rectangular area that defines a geographic area. In FME, the easiest way to define a search envelope is to use search envelope parameters.

Defining a search envelope is the most efficient method of selecting an area of interest because FME will read only the data that is necessary – it does not have to read an entire dataset. Search Envelope parameters apply to both vector and raster datasets and can be particularly efficient if the source format has a spatial index.

Most FME readers have parameters to define the search envelope of data that is being read:

Screenshot with blank search envelope min and max x and y parameters

The parameters include the x and y coordinates of the bounding box as well as a parameter that defines the coordinate system.

How to Define the Bounding Box

Using the minimum and maximum x and y parameters, define a bounding box that will be used to filter the input features. Only features that intersect with the bounding box are returned. Note that the bounding box intersection is not a full geometry intersection (based on spatial relationships) that would be returned by a transformer like the SpatialFilter.

Note  If all four coordinates of the search envelope are left at 0, the search envelope will be disabled even if this option is checked.

Search Envelope Coordinate System

Specifies the coordinate system of the search envelope if it is different than the coordinate system of the data. The coordinate system associated with the data to be read must always be set if this parameter is set.

If this parameter is set, the minimum and maximum points of the search envelope are reprojected from the Search Envelope Coordinate System to the reader’s coordinate system prior to applying the envelope.

Clip to Search Envelope

The underlying function for Use Search Envelope is an intersection; however, when Clip to Search Envelope is checked, a clipping operation is also performed.

  • When left unchecked (set to No), features that overlap the boundary will be included in their full (unclipped) form.
  • When checked (set to Yes), this option instructs FME to clip features to the exact envelope boundary. FME removes any portions of imported features being read that are outside the search envelope.

Clip to Search Envelope: No

Clip to Search Envelope: Yes

Any features that cross the search envelope boundary will be read, including the portion that lies outside of the boundary.

Any features that cross the search envelope boundary will be clipped at the boundary, and only the portion that lies inside the boundary will be read.

The search envelope includes the bounding box and the extent of the raster.

The search envelope includes only the area within the bounding box.

The raster size will still match the bounding box, but the area without data will be filled with Nodata values to represent the absence of data, if the source raster has them.

Raster Nodata may be a single value across all bands, a single value per band, or a separate alpha or transparency band that indicates the lack of data values (this is more common in images than other types of rasters).

Advanced

HTTPS certificate verification behavior is enabled (set to Yes) or disabled (set to No) by this parameter. By default, this parameter is set to Yes.

This parameter only applies to requests made in the Filter section of this reader (includes browsing for Catalogs/Collections/Items). However, if a web connection is specified under Use Authentication, this parameter is ignored and the certificate verification behavior will follow the web connection settings.

This parameter is always ignored when requesting assets. If a web connection is specified under Use Asset Authentication, certificate verification behavior for asset requests will follow the web connection settings. If a web connection is not specified, FME will not verify certificates when requesting assets.