> ## Documentation Index
> Fetch the complete documentation index at: https://docs.less.tech/llms.txt
> Use this file to discover all available pages before exploring further.

# Polygon

> Build polygons/area from coordinates or convert coordinate lists to polygons

The Polygon tool produces **polygons** in two different ways. Pair it with [Point-in-Polygon](/tools/utilities/point-in-polygon) or other workflows that expect a polygon column.

### Modes

1. **From coordinates** — start from a center latitude/longitude per row and call the isochrones service to build an area by **driving distance** or **driving time**.
2. **Convert from JSON** — start from a column of coordinate lists and close the ring to form a polygon without calling the isochrone API.

<Tabs>
  <Tab title="From coordinates">
    <Steps>
      <Step title="Polygon mode">
        Select **From coordinates**.
      </Step>

      <Step title="Latitude / longitude columns">
        Choose numeric columns for the center point of each polygon.
      </Step>

      <Step title="Range type">
        Pick **Distance** (kilometers) or **Time** (minutes) to control how large the polygons will be. For example, an area around a point with a 100 kilometer distance from the center point to the outer ring of the area is fairly. Conversely, a 5 minute drivetime distance from the center to the outer ring of the area is comparatively small.
      </Step>

      <Step title="Range">
        Select range.
        Distance can be between 1–100 kilometers. Time can between 1–180 minutes.
      </Step>

      <Step title="Smoothing">
        Adjust **0–100** to simplify or round the polygon boundary; higher values yield simpler, more rounded areas/polygons.
      </Step>
    </Steps>
  </Tab>

  <Tab title="Convert from JSON">
    <Steps>
      <Step title="Polygon mode">
        Select **Convert from JSON**.
      </Step>

      <Step title="Coordinates column">
        Choose a **List** column where each row is an array of objects with **`lat`** and **`lon`** keys. The tool builds a TopoJSON polygon in the output **`geometry`** column.
      </Step>
    </Steps>
  </Tab>
</Tabs>

### Outputs (summary)

* **From coordinates** — input columns are preserved where applicable; a **`geometry`** column holds the isochrone polygon (TopoJSON). Failed rows may include **`error`** and **`error_message`** fields.
* **Convert from JSON** — same row keys plus a **`geometry`** TopoJSON polygon per successful conversion.