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

# /vts

```
URL: http://<db.host>:<db.port>/vts
```

## Overview

*Kinetica* provides a *Vector Tile Service* (*VTS*) to generate Vector Tiles and
support client-side visualization of the geospatial data contained within the
tiles. The Vector Tile format generated follows the open standard *Mapbox*
[Vector Tile specification](https://github.com/mapbox/vector-tile-spec/tree/master/2.1).
The *Kinetica VTS* feeds a client-side Vector Tile renderer, such as
*Mapbox GL*, by adding the *VTS* URL to the renderer's style configuration as a
map layer source. Any *Kinetica* table or view that is defined with at least one
*WKT*-[type](/content/concepts/types) (geometry) column can be used as the
data source for the `layer` parameter. The data source, geographical
position, and zoom level of each Vector Tile are specified in a *VTS* request.
The requested Vector Tile is then returned in the response.

The VTS offers a couple advantages over server-side WMS calls:

* VTS supports client-side control of styling like image fill
* When using vector tiles, the browser only requests new information as needed
  and caches data along the way; WMS output must be re-rendered on every
  pan/zoom

<a id="vts-config" />

## Configuration

VTS is configured via the <Badge color="gray">gpudb.conf</Badge> configuration file.

Settings:

| Name                         | Default    | Description                                                                                                                                                                                                                                                                                      | Allowable Values |
| ---------------------------- | ---------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | ---------------- |
| `vts.max_vertices_per_chunk` | `20000000` | The maximum number of vertices within a chunk when rendering VTS tiles. If a chunk has more vertices than this limit, the VTS request will return an error.                                                                                                                                      | Minimum is `0`   |
| `vts.max_features_per_tile`  | `200000`   | The maximum number of features that will be returned in a VTS tile. This limit is applied at the chunk level, so the actual returned tile may have more features. If there are more features within the given tile within a chunk, the additional features will not be returned within the tile. | Minimum is `0`   |

<a id="vts-usage" />

## Usage

Base *VTS* URI:

```
http://<db.host>:<db.port>/vts/<layer>/<z>/<x>/<y>?attributes=<columns>
```

<Note>
  The *VTS* URL needs to be specified in the client-side visualizer's
  configuration.
</Note>

URI parameters:

| Name         | Description                             | Allowable Values                                                                                                                                                    |
| ------------ | --------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| `layer`      | Name of data source table or view.      | A valid table name, in `[schema_name.]table_name` format, using standard [name resolution rules](/content/concepts/tables#table-name-resolution)                    |
| `attributes` | List of column names.                   | A comma separated list of column names from the `layer` source table / view. Must include a single geometry column and may include additional non-geometry columns. |
| `z`          | Zoom level of the requested tile.       | Non-negative integer. The maximum value is 30. Provide the parameter as `{z}` to have the client-side renderer dynamically set the value.                           |
| `x`          | Horizontal index of the requested tile. | Non-negative integer. Provide the parameter as `{x}` to have the client-side renderer dynamically set the value.                                                    |
| `y`          | Vertical index of the requested tile.   | Non-negative integer. Provide the parameter as `{y}` to have the client-side renderer dynamically set the value.                                                    |

<a id="vts-example" />

## Example

Below is a snippet of a Javascript *Mapbox style specification* using Kinetica's
*VTS* URL as a source:

```
// Config
var tableName = "nyc_neighborhood";
var wktColumn = "geom";
var kineticaUrl = "http://localhost:9191/vts/";

// Mapbox GL
map.on('load', function () {
  map.addLayer({
    "id": tableName + "_layer",
    "version": 8,
    "type" : "fill",
    "source": {
      "type": "vector",
      "tiles": [kineticaUrl + tableName + "/{z}/{x}/{y}?attributes=" + wktColumn], // Note Mapbox uses the params in curly braces as dynamic values. Don't change those.
      "maxzoom": 20
    },
    "source-layer": tableName,
    "paint": {
      "fill-color": "#EDF00F",
      "fill-outline-color": "#000000"
    }
  });
});
```

<a id="vts-limitations" />

## Limitations and Cautions

* Since VTS sends feature information for each table row to the browser, the
  client can get overwhelmed with data; performance is dependent upon client
  hardware