The CARTO Maps API allows you to generate maps based on data hosted in your CARTO account.

MapConfig Aggregation Extension

1. Purpose

This specification describes an extension for MapConfig 1.7.0 version.

2. Changes over specification

This extension introduces a new layer options for aggregated data tile generation.

2.1 Aggregation options

The layer options attribute is extended with a new optional aggregation attribute. The value of this attribute can be false to explicitly disable aggregation for the layer.

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{
    aggregation: {

        // OPTIONAL
        // string, defines the placement of aggregated geometries. Can be one of:
        // * "point-sample", the default places geometries at a sample point (one of the aggregated geometries)
        // * "point-grid" places geometries at the center of the aggregation grid cells
        // * "centroid" places geometriea at the average position of the aggregated points
        // See https://github.com/CartoDB/Windshaft-cartodb/blob/master/docs/aggregation.md#placement for more details
        placement: "point-sample",

        // OPTIONAL
        // object, defines the columns of the aggregated datasets. Each property corresponds to a columns name and
        // should contain an object with two properties: "aggregate_function" (one of "sum", "max", "min", "avg", "mode" or "count"),
        // and "aggregated_column" (the name of a column of the original layer query or "*")
        // A column defined as `"_cdb_feature_count": {"aggregate_function": "count", aggregated_column: "*"}`
        // is always generated in addition to the defined columns.
        // The column names `cartodb_id`, `the_geom`, `the_geom_webmercator` and `_cdb_feature_count` cannot be used
        // for aggregated columns, as they correspond to columns always present in the result.
        // See https://github.com/CartoDB/Windshaft-cartodb/blob/master/docs/aggregation.md#columns for more details
        columns: {
            "aggregated_column_1": {
                "aggregate_function": "sum",
                "aggregated_column": "original_column_1"
            }
        },

        // OPTIONAL
        // Number, defines the cell-size of the spatial aggregation grid as a pixel resolution power of two (1/4, 1/2,... 2, 4, 16)
        // to scale from 256x256 pixels; the default is 1 corresponding to 256x256 cells per tile.
        // See https://github.com/CartoDB/Windshaft-cartodb/blob/master/docs/aggregation.md#resolution for more details
        resolution: 1,

        // OPTIONAL
        // Number, the minimum number of (estimated) rows in the dataset (query results) for aggregation to be applied.
        // See https://github.com/CartoDB/Windshaft-cartodb/blob/master/docs/aggregation.md#threshold for more details
        threshold: 500000
    }
}

History

1.0.0

  • Initial version