Image Quality: Standard vs Test Imagery

Planet’s data API provides metadata in regards to image quality. This falls into two categories: standard and test. The vast majority of published imagery falls into the standard category, meaning that it’s passed all Planet’s image quality metrics in the processing pipeline. To qualify for standard image quality an image must meet all of the following criteria:

  • sun altitude greater than or equal to 10 degrees
  • off nadir view angle less than 20 degrees
  • saturated pixels fewer than 20%
  • image has obtained at least 200 ground control points during rectification
  • band alignment threshold (based on across-track registration residuals) of less than 0.3 pixels for all band combinations.

The remaining published imagery falls into the test category. The majority of test-quality images are categorized this way due to no lack of ground lock, or less than 199 ground control points, band alignment of less than 0.5 pixels, or a high volume of no signal pixels.

For use cases that require fine positional accuracy, we recommend using images that have ground_lock: true. Test images are usable images and are appropriate for most use cases.

You can find whether an image is standard or test quality within the scene metadata in Explorer or via the Data API.

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