# Polygon Layer

Polygon Layer can display [GeoJSON](https://tools.ietf.org/html/rfc7946) features. GeoJSON supports the following geometry types: `Point`, `LineString`, `Polygon`, `MultiPoint`, `MultiLineString`, `MultiPolygon`.

Studio supports all the GeoJSON types above. You can pass in either a single [`Feature`](https://tools.ietf.org/html/rfc7946#section-3.2) or a [`FeatureCollection`](https://tools.ietf.org/html/rfc7946#section-3.3)

An example of the Polygon Layer.

A path GeoJSON layer can display data like trip routes or contours. Stroke color can be set with a numerical field.

Polygon Layer, filled and colored

A polygon GeoJSON layer is essentially a [choropleth](https://en.wikipedia.org/wiki/Choropleth_map) layer and works best for rendering geofences. Fill color or height can be set with a numerical field. For example, it can display population by census tracts.

Polygon Layer showing 3D buildings.

To add a Polygon Layer, your dataset must contain geometry data.

# GeoJSON Input

When upload a GeoJSON file contains FeatureCollection, a Polygon Layer will be auto-created.

**Example GeoJSON**

```json
{
  "type": "FeatureCollection",
  "features": [
    {
      "type": "Feature",
      "geometry": {
        "type": "Point",
        "coordinates": [102.0, 0.5]
      },
      "properties": {
        "prop0": "value0"
      }
    },
    {
      "type": "Feature",
      "geometry": {
        "type": "LineString",
        "coordinates": [
          [102.0, 0.0],
          [103.0, 1.0],
          [104.0, 0.0],
          [105.0, 1.0]
        ]
      },
      "properties": {
        "prop0": "value0"
      }
    }
  ]
}
```

Geometries (Polygons, Points, LineStrings etc) can be embedded into CSV as a GeoJSON or WKT formatted string.

1. **GeoJSON string**

```json
id,_geojson
1,"{\"type\":"Polygon\",\"coordinates\":[[[-74.158491,40.835947],[-74.157914,40.83902]]]}"
```

2. **WKT string**

Example data.csv with WKT string The [Well-Known Text (WKT)](https://dev.mysql.com/doc/refman/5.7/en/gis-data-formats.html#gis-wkt-format) representation of geometry values is designed for exchanging geometry data in ASCII form.

```json
id,_geojson
1,"POLYGON((0 0,10 0,10 10,0 10,0 0),(5 5,7 5,7 7,5 7, 5 5))"
```

# CSV Input

Paths can be created by joining a list of points from latitude and longitude, sort by an index field (e.g. timestamp) and group by unique ids.

Layer columns:

- **id:** \- required - A id column is used to group by points. Points with the same id will be joined into a single path.
- **lat:** \- required - The latitude of the point
- **lon:** \- required - The longitude of the point
- **alt:** \- optional - The altitude of the point
- **sort by:** \- optional - A sort by column is used to sort the points, if not specified, points will be sorted by row index.

**Example CSV**

| id | latitude | longitude | sort by |
| --- | --- | --- | --- |
| A | 40.81773 | -74.20986 | 0 |
| A | 40.81765 | -74.20987 | 1 |
| A | 40.81746 | -74.20998 | 2 |
| B | 40.64375 | -74.33242 | 0 |
| B | 40.64353 | -74.20987 | 1 |
| B | 40.64222 | -74.33001 | 2 |

# Filter Polygons

With polygons added to your map, you can select them to create geospatial boundaries that serve as a filter.

_Selecting a neighborhood polygon to filter suitability analysis results._

Learn more in the [geospatial filter documentation](https://docs.foursquare.com/analytics-products/docs/filters-geospatial#select-geometries).

# Settings

The follow sections detail every setting available in the Polygon Layer.

## Basic

Core settings for the Polygon Layer.

| Setting | Description |
| --- | --- |
| Layer Type | Must be Polygon to use the Polygon Layer. |
| Dataset | The dataset to use for the Polygon Layer. |
| Columns | The column(s) containing polygon data. |
| GeoJSON | A GeoJSON FeatureCollection to use for polygon generation. [See above](https://docs.foursquare.com/analytics-products/docs/layer-polygon#geojson-input). |
| Table columns | Tabular input used for polygon generation. [See above](https://docs.foursquare.com/analytics-products/docs/layer-polygon#csv-input). |

## Fill Color

Settings related to the fill color of the polygons.

| Setting | Description |
| --- | --- |
| Fill Color Toggle | Toggle on/off to show/hide fill color. |
| Color Based On | The field to base the fill color on. |
| Color Scale | The [color scale and palette](https://docs.foursquare.com/analytics-products/docs/layers-color-scale-and-palettes) for the fill color. |
| Opacity | The opacity of the fill color. 100 = fully opaque, 0 = fully transparent. |

## Stroke Color

Settings related to the stroke color of the polygons.

| Setting | Description |
| --- | --- |
| Stroke Toggle | Toggle on/off to show/hide stroke. |
| Stroke Color Based On | The field to base the stroke color on. |
| Stroke Color Scale | The [color scale and palette](https://docs.foursquare.com/analytics-products/docs/layers-color-scale-and-palettes) for the stroke color. |

## Stroke Width

Settings related to the stroke widths of the polygons.

| Setting | Description |
| --- | --- |
| Stroke Width | The stroke width in pixels. When based on a column, define a range instead of a static width. |
| Stroke Width Based On | A field to base stroke width on. |

## Height

Height settings for the polygon layer. Height is best viewed with the [3D viewing mode](https://docs.foursquare.com/analytics-products/docs/maps-view-modes).

| Setting | Description |
| --- | --- |
| Height Slider | Increase to raise the height of the layer's polygon. |
| Height Based On | An column to base the height off of. |
| Height Scale | Choose from linear, sqrt, and log. |
| Fixed Height | Applies height without additional modifications. |
| Shows Wireframe | Show the wireframes that define the polygon. |

Polygon Layer visualizing building footprints with fixed heights.

## Label

Label settings for the Polygon Layer. Labels are attached to each polygon.

| Setting | Description |
| --- | --- |
| Label Field | Select a field to display on the label. |
| Font Size | The size of the font to use on the label. |
| Font Color | The color of the label font. |
| Outline Width | The width of the outline in pixels. Set to `0` to disable the outline. |
| Outline Color | The color for the outline label. |
| Background Color | Toggle to enable a background color for the label. Choose a color with the color selector. |
| Text Anchor | Where, relative to the polygons, to anchor the text. Choose from start, middle, or end. |
| Alignment | How to align the text. Choose from top, middle, or bottom. |
| \+ Add More Labels | Add another label to the polygons. |

Polygons with labels.

# JSON Schema

For details on how to programmatically specify layer properties, refer to the [Layer Configuration](https://docs.foursquare.com/developer/docs/studio-layer-reference#geojson) specification.

Updated 5 months ago.