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

# PolyBuild

> Create a polygon or polyline from a set of coordinates

export const gemName_0 = "PolyBuild"

export const execution_engine_0 = "the SQL warehouse"

<Info>This gem runs in {execution_engine_0}.</Info>

## Overview

Build spatial shapes from coordinate data by grouping and ordering points into either polygons (closed shapes) or polylines (open lines). Use this gem to convert raw latitude/longitude values into structured spatial geometries for mapping, analysis, or downstream geospatial operations.

<Tip>
  The {gemName_0} gem has a corresponding interactive gem example. See [Interactive gem
  examples](/data-analysis/gems/gems#interactive-gem-examples) to learn how to run sample pipelines
  for this and other gems.
</Tip>

## Prerequisites

* Add `ProphecyDatabricksSqlSpatial` version 0.0.3 or higher to your project.

## Input and Output

The PolyBuild gem accepts the following input and output.

| Port    | Description                                                                                                                                                                       |
| ------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| **in0** | Input dataset containing pairs of columns with latitude and longitude coordinates, along with fields for grouping and ordering coordinates.                                       |
| **out** | Output dataset with one row per group, each containing a generated polygon or polyline in [WKT](https://en.wikipedia.org/wiki/Well-known_text_representation_of_geometry) format. |

## Parameters

Configure the PolyBuild gem using the following parameters.

| **Parameter**         | **Description**                                                                                                                                                                                                                                   |
| --------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| Build Method          | Select the type of spatial geometry to create from your coordinate data:<ul><li>Select **Sequence Polygon** for closed areas, such as boundaries or zones</li><li>Select **Sequence Polyline** for open paths, such as routes or trails</li></ul> |
| Longitude Column Name | Column containing longitude values. Must be in decimal degrees (e.g., `-122.4194`).                                                                                                                                                               |
| Latitude Column Name  | Column containing latitude values. Must be in decimal degrees (e.g., `37.7749`).                                                                                                                                                                  |
| Group Field           | Column used to divide coordinates into distinct shapes. <br />Example: Use the `state_name` column to identify polygons for each state border.<br />*Only one column is supported for grouping.*                                                  |
| Sequence Field        | Column that defines the drawing order of points within each group. <br />This column can be any sortable type (e.g., integers, timestamps, strings). <br />The points will be connected in ascending order.                                       |

<Note>
  * Sequence Polygon: Uses the `POLYGON()` format to create a closed shape.
  * Sequence Polyline: Uses the `LINESTRING()` format to create an open path.
</Note>

## Example

Assume you have the following `routes` table for public transportation routes.

<div class="table-example">
  | route\_id        | stop\_schedule       | latitude | longitude |
  | ---------------- | -------------------- | -------- | --------- |
  | bus\_21\_morning | 2025-07-16T08:00:00Z | 37.7749  | -122.4194 |
  | bus\_21\_morning | 2025-07-16T08:10:00Z | 37.7793  | -122.4192 |
  | bus\_21\_morning | 2025-07-16T08:20:00Z | 37.7796  | -122.4148 |
  | tram\_5\_evening | 2025-07-16T18:00:00Z | 34.0522  | -118.2437 |
  | tram\_5\_evening | 2025-07-16T18:10:00Z | 34.0565  | -118.2470 |
  | tram\_5\_evening | 2025-07-16T18:20:00Z | 34.0580  | -118.2417 |
</div>

To transform each route into a polyline geometry:

1. Add the PolyBuild gem to your pipeline canvas.
2. Connect the `routes` table to the PolyBuild input port.
3. Open the PolyBuild gem configuration.
4. For **Build Method**, select **Sequence Polyline**.
5. For **Longitude Column Name**, select the `longitude` column.
6. For **Latitude Column Name**, select the `latitude` column.
7. For **Group Field**, select the `route_id` column.
8. For **Sequence Field**, select the `stop_schedule` column.
9. Save and run the gem.

### Result

The PolyBuild gem outputs a table including a polyline for each route.

<div class="table-example">
  | route\_id        | wkt                                                                    |
  | ---------------- | ---------------------------------------------------------------------- |
  | bus\_21\_morning | `LINESTRING (-122.4194 37.7749, -122.4192 37.7793, -122.4148 37.7796)` |
  | tram\_5\_evening | `LINESTRING (-118.2437 34.0522, -118.2470 34.0565, -118.2417 34.0580)` |
</div>