𝗖𝗮𝗻 𝗜 𝗳𝗶𝗹𝘁𝗲𝗿 𝘀𝗲𝗮𝗿𝗰𝗵 𝗿𝗲𝘀𝘂𝗹𝘁𝘀 𝗯𝘆 𝗰𝗹𝗼𝘂𝗱 𝗰𝗼𝘃𝗲𝗿 𝗼𝗿 𝘃𝗶𝗲𝘄𝗶𝗻𝗴 𝗮𝗻𝗴𝗹𝗲?

You can fine-tune your archive search on SkyFi to get better image results. Here’s how filters like cloud cover, viewing angle, and overlap ratio work when using the POST /archives endpoint.

𝘾𝙡𝙤𝙪𝙙 𝘾𝙤𝙫𝙚𝙧𝙖𝙜𝙚 𝙁𝙞𝙡𝙩𝙚𝙧: Use the “maxCloudCoveragePercent” parameter. For example, if you set “maxCloudCoveragePercent”: 10, the API will only return images where the reported cloud cover is 10% or less. This is especially useful for optical imagery where clouds can obscure the ground. If you want any images regardless of clouds, you can set this to 100 (or simply omit it, as 100% is effectively the default maximum).

𝙊𝙛𝙛-𝙉𝙖𝙙𝙞𝙧 𝘼𝙣𝙜𝙡𝙚 𝙁𝙞𝙡𝙩𝙚𝙧: Use the “maxOffNadirAngle” parameter. This limits the camera angle of the satellite relative to directly overhead (nadir). A smaller angle (close to 0°) means the satellite was almost directly above the target, which generally yields less distortion and better image quality. If you set, say, “maxOffNadirAngle”: 20, you will get images taken from fairly overhead views (within 20 degrees of vertical). Higher angles (oblique shots) can cover your area but with more perspective distortion and possibly lower resolution on the ground.

𝙈𝙞𝙣𝙞𝙢𝙪𝙢 𝙊𝙫𝙚𝙧𝙡𝙖𝙥: Another related filter is “minOverlapRatio”. This ensures that the image at least covers a certain fraction of your AOI. For example, “minOverlapRatio”: 0.5 would only return images where at least 50% of your AOI is within the image footprint. This helps avoid cases where an image marginally intersects your area.

𝙎𝙤𝙧𝙩𝙞𝙣𝙜 (𝙞𝙢𝙥𝙡𝙞𝙘𝙞𝙩) : The API does not explicitly let you sort results by these criteria in the request, but you can retrieve all matches (up to the page size) and then client-side choose images with the best cloud/angle if multiple are available. Often, archive search results will include these fields so you can pick the best image for your needs.

By using these filters, you can fine-tune your search to get only high-quality imagery (clear and near-nadir). Keep in mind that stricter filters may result in fewer or even zero results if the criteria are hard to meet in the given time range and area. It may be useful to start with looser criteria (e.g., 50% clouds, 30° off-nadir) and then narrow down if too many results are returned.