What is an Area of Interest (AOI) in the SkyFi API, and how do I specify it?

The Area of Interest (AOI) defines the geographic area you are interested in for searching or ordering imagery. In the SkyFi API, the AOI must be provided as a polygon in WKT (Well-Known Text) format:

• The polygon should be specified in longitude and latitude coordinates (WGS84).

• Example WKT polygon format:

• Convex polygon required: The AOI should be a simple convex polygon (no self-intersecting or concave shapes). Typically rectangles or gently curved polygons work best.

• Vertex and size limits: There are some constraints on AOIs:

  • Maximum 500 vertices for any AOI polygon.

  • For archive searches and notifications, the area enclosed by the AOI must not exceed 500,000 square kilometers (which is a very large area, bigger than California for reference).

  • For orders, there may be minimum and maximum area limits depending on the provider or product (e.g., some high-resolution satellites have a minimum order size of a few sq km). Each archive metadata includes minSqKm and maxSqKm which indicate the allowable ordering area for that image.

• Calculating AOI area: It’s often useful to calculate the area of your AOI in square kilometers, since pricing and feasibility can depend on area. SkyFi provides a sample Python notebook to help calculate the area of a polygon AOI. By using that notebook or similar GIS methods, you can ensure your AOI meets any area requirements and estimate costs.

• Generating AOI by center point: If you want to create a square AOI around a central point with a specified area, SkyFi provides another sample notebook. You input a center coordinate and desired area (sq km), and it outputs a square polygon WKT for use as your AOI.

In practice, when using the API you will include the AOI WKT string in your JSON payload. Make sure to format it exactly as required (POLYGON keyword, double parentheses, and coordinates). If the AOI is invalid or too large, the API will return a validation error (HTTP 422).