Natural Footprint

Overview

Umbra's standard 5km x 5km Spotlight product ensures consistent high-quality imaging across the entire imaged area. However, for customers prioritizing larger ground coverage, Umbra offers Natural Footprint (NFP), which provides larger, geometry-driven scene sizes—commonly in the range of between 7.5 × 11 km up to 16 × 10 km without a fixed maximum. This comes with a trade-off, as the product quality diminishes outside the standard 5 x 5km area, with factors like increased file size, variable range resolution, decreased terrain-to-noise ratio, beam roll-off, and ambiguity artifacts. These artifacts include visible antenna patterns, decreased brightness towards the edges, and the appearance of fuzzy objects.

Usage

Our Natural Footprint (NFP) option offers a larger scene size compared to our 5×5 km scenes, though the exact size varies with collection geometry—grazing angle being the most significant driver. We recommend using the same default grazing angles for NFP as for 5 × 5 km scenes to maintain more consistent image quality. Advanced users can push these limits using Advanced Parameters: lowering the grazing angle typically increases the footprint, but may result in less uniform quality toward the edges.

NFP is ideal for customers who:

Prioritize maximum area coverage (e.g., urgent maritime or mobilization operations), where the advantages of larger scene sizes can outweigh the costs in time-sensitive scenarios.
Require regular monitoring of areas larger than 5 × 5 km. We can work with you to plan optimal geometries for your outcomes—please reach out for help.

To create a Task with a Natural Footprint, set Task.spotlightConstraints.sceneSize to NATURAL_FOOTPRINT. See Create Feasibility and Create Task.

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The Extended Scene Size product is not enabled by default for Canopy accounts. This product utilizes a low grazing angle in order to generate the large footprint. This is great for certain use cases (especially ship detection), but not for all use cases. If you would like to activate this product for your Canopy account, please contact us at [email protected] so that we may advise on it's utility for your needs.

Trade-Offs

File Size

Extended area data products are up to 10x larger than the standard 5km x 5km product.

Variable Range Resolution

Outside the standard 5km x 5km area, the range resolution may degrade and become coarser.

Decreased Terrain-to-Noise Ratio

Outside the standard 5km x 5km area, the noise floor raises resulting in a decrease in terrain-to-noise ratio (TNR). At the extreme, parts of the image may be completely black.

Beam Roll-Off

For very large processing, a visible antenna pattern could be present within the image. The tell-tale sign of this artifact is vignetting, a reduction of an image's brightness away from the center of the image.

Ambiguity Artifacts

In an extended area product, large, squarish fuzzy objects might appear at the edges of the scene.

Examples

Natural Footprint imagery is shown below. Artifacts outlined above are present:

Ambiguities can be seen on the scene edges
Beam Roll-Off is present as the brightness decreases away from the scene center.
The terrain-to-noise ratio decreases as a result of the beam roll-off.

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The square footprint in each example shows the coverage of a standard 5x5 km scene size for reference.

Santiago, Chile, 1 m x 1-look, NFP scene size 7.5x11 km

Miami, FL, USA, 1 m x 4 Looks, NFP scene size 12x8.5 km

Mexico City, Mexico, 1 m x 4 looks, NFP Scene Size 16x10 km

Toronto, Canada, 0.5 m x 3 looks, NFP Scene Size 12x8.5 km