CARTO for deck.gl

CARTO for deck.gl

Using the CartoLayer

Introduction

The CartoLayer is a deck.gl CompositeLayer used to visualize geospatial data from the CARTO platform.

It is compatible with the different versions of the CARTO Maps API (v1, v2, and v3) and is responsible for connecting to the platform in order to retrieve the data for visualization.

Connecting to CARTO 3

  1. Go to the Workspace and create a new connection:

  1. Create a token using our token API with access to the required table.

     1
     2
     3
     4
     5
     6
     7
     8
     9
    10
    11
    
    curl --location -g --request POST 'https://gcp-us-east1.api.carto.com/v3/tokens?access_token=eyJhb...' \
     --header 'Content-Type: application/json' \
     --data-raw '{
         "grants": [
             {
                 "connection_name": "bqconn",
                 "source": "cartobq.public_account.populated_places"
             }
         ],
          
     }'
    
  2. Set connection parameters

    A function setDefaultCredentials is provided to define the connection parameters to CARTO:

    1
    2
    3
    4
    5
    
    setDefaultCredentials({
      apiBaseUrl: 'https://gcp-us-east1.api.carto.com',
      apiVersion: API_VERSIONS.V3,
      accessToken: 'eyJhbGciOiJIUzI1NiJ9.eyJhIjoiYWNfbHFlM3p3Z3UiLCJqdGkiOiI1YjI0OWE2ZCJ9.Y7zB30NJFzq5fPv8W5nkoH5lPXFWQP0uywDtqUg8y8c'
    });
    

    For more info about the parameters of this function, check the reference.

  3. Create a layer using the previously created connection:

    1
    2
    3
    4
    5
    6
    7
    8
    
    new CartoLayer({
      id: 'places',
      connection: 'bqconn',
      type: MAP_TYPES.TABLE,
      data: 'cartobq.public_account.populated_places',
      pointRadiusMinPixels: 2,
      getFillColor: [200, 0, 80],
    }),
    

    View the complete example here


Geometry column

By default, the data source you specify in the data property must contain a column named “geom” with the geometry. If the column containing the geometry has a different name, you can still use it but you need to do the following:

  • If the type is MAP_TYPES.QUERY, you need to alias the geometry column to geom

  • If the type is MAP_TYPES.TABLE, you need to specify the name of the column containing the geometry using the geoColumn property.

Support for other deck.gl layers

The CartoLayer uses the GeoJsonLayer for rendering but you can also use any other deck.gl layer for rendering using the getData function from the CARTO module. This works for datasets with less than 200k rows but not for bigger datasets where you need to use a tileset.

This function receives an object with the following properties:

If the format is not explicitly specified, getData will pick a format automatically, depending on what is available from the CARTO API. The getData function returns an Object with the following properties:

  • format: the format of the returned data
  • data: the actual data response
 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
import { getData, FORMATS } from '@deck.gl/carto';
import { H3HexagonLayer } from '@deck.gl/geo-layers/';

const result =  await getData({
  type: MAP_TYPES.QUERY,
  source: `SELECT `carto-un`.h3.ST_ASH3(internal_point_geom, 4) as h3, count(*) as count
              FROM bigquery-public-data.geo_us_census_places.us_national_places 
            GROUP BY h3`,
  connection: 'connection_name',
  format: FORMATS.JSON
});
const data = result.data;

new H3HexagonLayer({
  data,
  filled: true,
  getHexagon: d => d.h3,
  getFillColor: d => [0, (1 - d.count / 10) * 255, 0],
  getLineColor: [0, 0, 0, 200],
});