s2-tools/dist/readers/shapefile/mmap.js

A collection of geospatial tools primarily designed for WGS84, Web Mercator, and S2.

import { DataBaseFile } from './dbf';
import { MMapReader } from '../mmap';
import { ShapeFileReader } from './shp';
import { Transformer } from '../../proj4';
import { shapefileFromGzip } from '.';
import { exists, readFile } from 'fs/promises';
export * from './dbf';
export * from './shp';
/**
 * Assumes the input is pointing to a shapefile or name without the extension.
 * The algorithm will find the rest of the paths if they exist.
 * @param input - the path to the .shp file or name without the extension
 * @returns - a Shapefile
 */
export async function shapefileFromPath(input) {
    if (input.endsWith('.zip')) {
        const gzipData = await readFile(input);
        return shapefileFromGzip(gzipData.buffer);
    }
    const path = input.replace('.shp', '');
    const shp = `${path}.shp`;
    const dbf = `${path}.dbf`;
    const prj = `${path}.prj`;
    const cpg = `${path}.cpg`;
    if (!(await exists(shp)))
        throw new Error('Shapefile does not exist');
    const definition = {
        shp,
        dbf: (await exists(dbf)) ? dbf : undefined,
        prj: (await exists(prj)) ? prj : undefined,
        cpg: (await exists(cpg)) ? cpg : undefined,
    };
    return shapefileFromDefinition(definition);
}
/**
 * Build a Shapefile from a Definition
 * @param def - a description of the data to parse
 * @returns - a Shapefile
 */
export async function shapefileFromDefinition(def) {
    const { shp, dbf, prj, cpg } = def;
    const encoding = cpg !== undefined ? await readFile(cpg, { encoding: 'utf8' }) : 'utf8';
    const transform = prj !== undefined ? new Transformer(await readFile(prj, { encoding: 'utf8' })) : undefined;
    const dbfReader = dbf !== undefined ? new MMapReader(dbf) : undefined;
    const databaseFile = dbfReader !== undefined ? new DataBaseFile(dbfReader, encoding) : undefined;
    return new ShapeFileReader(new MMapReader(shp), databaseFile, transform);
}
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