Deep Dive Into the Composite Tool

The composite Tool is designed to simplify the process of merging multiple image inputs into a single composite, optimizing quota usage by eliminating unnecessary overlap between scenes and reduce the file size, and it is compatible with various item and bundle types. Its use is straightforward, with two current options available: Full Composite and Stripped Per Image Strip.

{
  "name": "composite_example",
  "products": [
    {
      "item_ids": [
        "20200710_172116_0e19",
        "20200710_172117_0e19"
      ],
      "item_type": "PSScene",
      "product_bundle": "analytic_udm2"
    }
  ],
  "tools": [
    {
      "composite": {}  // or "composite": {"group_by": "strip_id"}
    }
  ]
}

However, users should understand its functionality and purpose in order to create effective composites. Its constraints are more strategic and may affect its applicability in certain scenarios.

Key Tips for Using the Composite Tool:

1. Select Assets Carefully:
   Before making a selection, please ensure you specify the time interval and review the asset history. When creating compositions that involve time aspects, it's crucial to establish a consistent time range. This consistency will ensure that your data is meaningful, especially if other composites are used in the analysis.
   
   On the flip side, remove redundant scenes that completely overlap each other or are unnecessary. For instance, in the case below, there is a PlanetScope's scene footprint and an AOI. It's evident that there's no need to use the composite too
   
   
   
   Please keep in mind that the more scenes included in a composite, the longer it may take to process, bundle, and deliver. Additionally, incorporating extra scenes can result in the aggregation of unnecessary metadata into the final deliverable, as demonstrated in the example below:
   
   
   All metadata for each scene is added to the compressed delivered file, which is a side effect of merging scenes.  

2. Verify Instrument Compatibility: Ensure that all assets come from the same family and generation of instruments to maintain consistency.

3. Coordinate System and Band Configuration: All input products must share the same coordinate system (i.e., EPSG code), band configuration, and pixel type. While the input products can have different resolutions, the output composite will match the resolution of the first product file. The composite tool processes images in the order they are added, with later images overlaying earlier ones. The final output reflects the order in which products are included.

4. Composite is no data Cube: When downloading a collection of images, you can order them all at once, but note that the Composite tool cannot be used. Using this tool will instruct our system to combine all assets into one.

Important Notes:

Products like SkySatCollect are pre-composited and cannot be further combined. Bundles with non-orthorectified images (e.g., basic_* bundles) are unsuitable for compositing due to the need for rectification to ensure accurate alignment.
A single composite image will be provided for each set of product bundles, and Universal Data Models (UDMs) will also be combined into one file, with "_composite" added to the filenames.
The tool processes these files using RPC and XML files for guidance.

Understanding these guidelines will help you effectively utilize the composite tool and produce accurate and meaningful image composites. To learn more about our toolschain, please, refer to our developer center page.