@deck.gl/carto/dist/layers/cluster-utils.js

CARTO official integration with Deck.gl. Build geospatial applications using CARTO and Deck.gl.

// deck.gl
// SPDX-License-Identifier: MIT
// Copyright (c) vis.gl contributors
import { cellToParent } from 'quadbin';
import { cellToParent as h3CellToParent, getResolution as getH3Resolution } from 'h3-js';
import { log } from '@deck.gl/core';
import { createBinaryPointFeature, createEmptyBinary } from "../utils.js";
/**
 * Aggregates tile by specified properties, caching result in tile.userData
 *
 * @returns true if data was aggregated, false if cache used
 */
export function aggregateTile(tile, tileAggregationCache, aggregationLevels, properties = [], getPosition, getWeight, scheme = 'quadbin') {
    if (!tile.content)
        return false;
    // Aggregate on demand and cache result
    if (!tile.userData)
        tile.userData = {};
    const cell0 = tileAggregationCache.get(aggregationLevels)?.[0];
    if (cell0) {
        // Have already aggregated this tile
        if (properties.every(property => property.name in cell0)) {
            // Use cached result
            return false;
        }
        // Aggregated properties have changed, re-aggregate
        tileAggregationCache.clear();
    }
    const out = {};
    for (const cell of tile.content) {
        let id = cell.id;
        const position = typeof getPosition === 'function' ? getPosition(cell, {}) : getPosition;
        // Aggregate by parent rid
        for (let i = 0; i < aggregationLevels - 1; i++) {
            if (scheme === 'h3') {
                const currentResolution = getH3Resolution(id);
                id = h3CellToParent(id, Math.max(0, currentResolution - 1));
            }
            else {
                id = cellToParent(id);
            }
        }
        // Use string key for both H3 and Quadbin to avoid TypeScript Record<bigint, any> issues
        // https://github.com/microsoft/TypeScript/issues/46395
        const parentId = String(id);
        if (!(parentId in out)) {
            out[parentId] = { id, count: 0, position: [0, 0] };
            for (const { name, aggregation } of properties) {
                if (aggregation === 'any') {
                    // Just pick first value for ANY
                    out[parentId][name] = cell.properties[name];
                }
                else {
                    out[parentId][name] = 0;
                }
            }
        }
        // Layout props
        const prevTotalW = out[parentId].count;
        out[parentId].count += typeof getWeight === 'function' ? getWeight(cell, {}) : getWeight;
        const totalW = out[parentId].count;
        const W = totalW - prevTotalW;
        out[parentId].position[0] = (prevTotalW * out[parentId].position[0] + W * position[0]) / totalW;
        out[parentId].position[1] = (prevTotalW * out[parentId].position[1] + W * position[1]) / totalW;
        // Re-aggregate other properties so clusters can be styled
        for (const { name, aggregation } of properties) {
            const prevValue = out[parentId][name];
            const value = cell.properties[name];
            if (aggregation === 'average') {
                out[parentId][name] = (prevTotalW * prevValue + W * value) / totalW;
            }
            else if (aggregation === 'count' || aggregation === 'sum') {
                out[parentId][name] = prevValue + value;
            }
            else if (aggregation === 'max') {
                out[parentId][name] = Math.max(prevValue, value);
            }
            else if (aggregation === 'min') {
                out[parentId][name] = Math.min(prevValue, value);
            }
        }
    }
    tileAggregationCache.set(aggregationLevels, Object.values(out));
    return true;
}
export function extractAggregationProperties(tile) {
    const properties = [];
    const validAggregations = ['any', 'average', 'count', 'min', 'max', 'sum'];
    for (const name of Object.keys(tile.content[0].properties)) {
        let aggregation = name.split('_').pop().toLowerCase();
        if (!validAggregations.includes(aggregation)) {
            log.warn(`No valid aggregation present in ${name} property`)();
            aggregation = 'any';
        }
        properties.push({ name: name, aggregation });
    }
    return properties;
}
export function computeAggregationStats(data, properties) {
    const stats = {};
    for (const { name, aggregation } of properties) {
        stats[name] = { min: Infinity, max: -Infinity };
        if (aggregation !== 'any') {
            for (const d of data) {
                stats[name].min = Math.min(stats[name].min, d[name]);
                stats[name].max = Math.max(stats[name].max, d[name]);
            }
        }
    }
    return stats;
}
export function clustersToBinary(data) {
    const positions = new Float32Array(data.length * 2);
    const featureIds = new Uint16Array(data.length);
    for (let i = 0; i < data.length; i++) {
        positions.set(data[i].position, 2 * i);
        featureIds[i] = i;
    }
    return {
        ...createEmptyBinary(),
        points: createBinaryPointFeature(positions, featureIds, featureIds, {}, data)
    };
}
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