@openaip/coordinate-parser NPM

OpenAIP Coordinate Parser

Easily extendable and configurable parser for NodeJS and the browser that extracts coordinates from a variety of formatted lat/lon strings. The main focus is parsing various decimal or DMS format variations. Contributions that add other format parsers are always welcome!

Usage

The parser provides parsing all known formats right out-of-the-box:

import { Parser } from '@openaip/openaip-coordinate-parser';

const coordinateString = '12.5678 45.6789';
const coordinates = parser.parse(coordinateString);
const latitude = coordinates.latitude; // 12.5678
const longitude = coordinates.longitude; // 45.6789

Configuration

For advanced use-cases and to speed up performance, the parser can be configured according to requirements. For example, if only parsing a known number of coordinate formats is required, the used format parsers can be reduced to only the required ones. Each format parser can be configured individually:

import { Parser } from '@openaip/openaip-coordinate-parser';
import { DecimalSignedFormat } from '@openaip/openaip-coordinate-parser/formats/decimal-signed-format.js';
import { DecimalUnsignedFormat } from '@openaip/openaip-coordinate-parser/formats/decimal-unsigned-format.js';

// only parsing two formats is ever required
const decimalParser = new DecimalUnsignedFormat({ precision: 5 });
const decimalSexaParser = new DecimalSignedFormat({ precision: 5 });
// only use two parsers instead of all default ones
const parser = new Parser({ formatParsers: [decimalParser, decimalSexaParser] });

parser.parse(`12.5678 45.6789`);
parser.getLatitude(); // 12.5678
parser.getLongitude(); // 45.6789

const coordinates = parser.parse(`1.234° 5.678°`);
const latitude = coordinates.latitude; // 1.234
const longitude = coordinates.longitude; // 5.678

Extending the parser

The parser can easily be extended with custom parsing logic. Simply provide your own format parser that provides the parse, canParse and reset methods. The canParse method must return true if the parser is able to parse given coordinate string, false if not. The parse method is used to extract decimal longitude and latitude values from the coordinate string. Please note that the ordering of format parsers is crucial if two parsers may be able to parse the same format - first parser identified with canParse wins!

import { Parser } from '@openaip/openaip-coordinate-parser';
import { IFormatParser } from '@openaip/openaip-coordinate-parser/formats/base-format.js';
import { DecimalUnsignedFormat } from '@openaip/openaip-coordinate-parser/formats/decimal-format.js';

// available format parser
const decimalParser = new DecimalUnsignedFormat({ precision: 5 });
// your custom format parser
export class MyCustomFormatParser implements IFormatParser {
    parse(coordinateString: string): Coordinate {
        // custom parser logic
        const { lat, lon} = parseWithCustomLogic(coordinateString);

        return {
            latitude: parseFloat(lat),
            longitude: parseFloat(lon),
        };
    }

    static canParse(coordinateString: string): boolean {
        // verify that the parser can actually parse the string - if true, the parser will be used to parse the coordinates
        return /^.*$/.test(coordinateString);
    }

    reset() {
        // do reset logic
    }
}

// initialize your custom format parser
const customFormatParser = new MyCustomFormatParser();
// extend with your custom format parser
const parser = new Parser({ formatParsers: [customFormatParser, decimalParser] });

Supported Formats

Currently the out-of-the-box format parsers supports the following various formats and also handles their possible variations, i.e. with or without whitespaces and comma, gracefully: