@seasketch/geoprocessing/dist/src/dataproviders/getFeaturesForSketchBBoxes.js

Geoprocessing and reporting framework for SeaSketch 2.0

import { loadFgb } from "./flatgeobuf.js";
import { toSketchArray } from "../helpers/index.js";
import md5 from "spark-md5";
import { bbox } from "@turf/turf";
import { splitBBoxAntimeridian } from "../toolbox/antimeridian.js";
/**
 * Loads features from a FlatGeobuf referenced by URL, which intersect the
 * bounding boxes of each individual sketch in a SketchCollection, or a single
 * Sketch.
 *
 * In the case of a SketchCollection, it is possible that duplicate features may
 * be fetched in the case of overlapping bounding boxes or very large features
 * that span multiple bounding boxes. This function will de-dupe those features.
 * The caller can
 * provide a uniqueIdProperty to de-dupe features (faster), otherwise a hash of
 * the feature coordinates will be used (slower).
 *
 * If uniqueIdProperty is not provided, there is the potential for elimination
 * of features that are geometrically identical but have different properties.
 *
 * @param sketch Sketch or SketchCollection
 * @param fgbUrl FlatGeobuf location
 * @param options.uniqueIdProperty name of unique ID property to de-dupe
 * features
 * @returns array of Features
 */
export async function getFeaturesForSketchBBoxes(sketch, fgbUrl, options = {}) {
    const sketchBoxes = toSketchArray(sketch).map((sketch) => bbox(sketch));
    const features = await getFeaturesForBBoxes(sketchBoxes, fgbUrl, options);
    return features;
}
/**
 * Loads features from a FlatGeobuf referenced by URL, which intersect the
 * bounding boxes. Deduplicates features given uniqueIdProperty (faster) or
 * using md5 hash of feature coordinates (slower).
 *
 * It is possible that duplicate features may be fetched in the case of
 * overlapping bounding boxes. This function will de-dupe those features. The caller can
 * provide a uniqueIdProperty to de-dupe features (faster), otherwise a hash of
 * the feature coordinates will be used (slower).
 *
 * If uniqueIdProperty is not provided, there is the potential for elimination
 * of features that are geometrically identical but have different properties.
 *
 * @param bboxes the bounding boxes to fetch features for
 * @param fgbUrl the URL of the FlatGeobuf file
 * @param options.uniqueIdProperty name of unique ID property to de-dupe
 * features
 * @returns array of Features
 */
export async function getFeaturesForBBoxes(bboxes, fgbUrl, options = {}) {
    const { uniqueIdProperty } = options;
    const features = [];
    const addedIdentifiers = new Set();
    await Promise.all(bboxes.map(async (box) => {
        const splitBoxes = splitBBoxAntimeridian(box);
        const results = (await Promise.all(splitBoxes.map(async (box) => {
            return await loadFgb(fgbUrl, box);
        }))).flat();
        for (const feature of results) {
            // feature.id is not supported in flatgeobuf format on creation, but we can look for user-defined
            let id;
            if (!id) {
                if (uniqueIdProperty) {
                    if (feature.properties?.[uniqueIdProperty] === undefined) {
                        throw new Error(`uniqueIdProperty ${uniqueIdProperty} not found in feature properties`);
                    }
                    id = feature.properties?.[uniqueIdProperty];
                }
                else {
                    id = md5.hash(JSON.stringify(feature.geometry.coordinates));
                }
            }
            if (id && !addedIdentifiers.has(id)) {
                addedIdentifiers.add(id);
                features.push(feature);
            }
        }
    }));
    return features;
}
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