Crate locat 

locat

A blazing fast, zero-copy ISO 6709 geographic coordinate parser and writer in Rust.

Features

• Zero-copy: CRS identifiers borrow directly from the input string
• no_std compatible: works without the standard library
• All ISO 6709 notation forms: decimal degrees, degrees+minutes, DMS
• Altitude & CRS: optional altitude (meters) and coordinate reference system identifier
• Round-trip: Display impls produce valid ISO 6709 output
• DFA-powered lexer: logos-based tokenizer classifies components in a single pass

Installation

[dependencies]
locat = "0.1"

Quick Start

use locat::parse;

// Decimal degrees (New York City)
let coord = parse("+40.7128-074.0060/").unwrap();
let (lat, lon): (f64, f64) = coord.to_decimal_degrees();
assert!((lat - 40.7128).abs() < 1e-10);
assert!((lon - (-74.006)).abs() < 1e-10);

// Degrees, minutes, seconds
let coord = parse("+404243-0740002/").unwrap();

// With altitude and CRS (Mount Everest)
let coord = parse("+27.5916+086.5640+8848CRSepsg4326/").unwrap();
assert!(coord.altitude().is_some());
assert_eq!(coord.crs().unwrap().as_str(), "epsg4326");

// Round-trip
let input = "+40.7128-074.0060/";
let coord = parse(input).unwrap();
assert_eq!(coord.to_string(), input);

Supported Formats

Form	Latitude	Longitude	Example
Degrees	±DD[.D+]	±DDD[.D+]	+40.7128-074.0060/
Deg+Min	±DDMM[.M+]	±DDDMM[.M+]	+4042.77-07400.36/
DMS	±DDMMSS[.S+]	±DDDMMSS[.S+]	+404243.0-0740002.0/

Optional trailing components: [±Altitude][CRS<id>]/

Benchmarks

Measured on Apple Silicon with cargo bench (Criterion). All times are per-operation.

Parse (single coordinate)

Format	Time	Throughput
Minimal (+00+000/)	~18 ns	424 MiB/s
DMS integer (+404243-0740002/)	~22 ns	704 MiB/s
Decimal degrees (+40.7128-074.0060/)	~27 ns	634 MiB/s
Deg+Min (+4042.7700-07400.3600/)	~30 ns	708 MiB/s
DMS decimal (+404243.123000-0740002.456000/)	~34 ns	840 MiB/s
With altitude (+27.5916+086.5640+8848/)	~32 ns	680 MiB/s
With altitude+CRS (+27.5916+086.5640+8848CRSepsg4326/)	~37 ns	884 MiB/s

Round-trip (parse + Display)

Format	Time
DMS integer	~184 ns
Minimal	~180 ns
DMS decimal	~339 ns
Decimal degrees	~489 ns
Deg+Min	~497 ns
With altitude	~556 ns
With altitude+CRS	~622 ns

Conversion

to_decimal_degrees() completes in ~1 ns regardless of input format.

Batch throughput

Parsing 1,000 mixed-format coordinates: ~48 µs (~430 MiB/s).

Run benchmarks yourself:

cargo bench

License

locat is under the terms of both the MIT license and the Apache License (Version 2.0).

See LICENSE-APACHE, LICENSE-MIT for details.

Copyright (c) 2026 Al Liu.

Structs

Altitude

Altitude in meters.

Coordinate

A parsed ISO 6709 geographic coordinate.

CrsId

CRS (Coordinate Reference System) identifier.

LatDMS

Degrees, minutes, and decimal seconds latitude: ±DDMMSS.SSS.

LatDeg

Decimal degrees latitude: ±DD.DDD (0.0–90.0).

LatDegMin

Degrees and decimal minutes latitude: ±DDMM.MMM.

LonDMS

Degrees, minutes, and decimal seconds longitude: ±DDDMMSS.SSS.

LonDeg

Decimal degrees longitude: ±DDD.DDD (0.0–180.0).

LonDegMin

Degrees and decimal minutes longitude: ±DDDMM.MMM.

Enums

Component

Which coordinate component caused a range error.

Latitude

Latitude component of an ISO 6709 coordinate.

Longitude

Longitude component of an ISO 6709 coordinate.

ParseError

Errors that can occur when parsing an ISO 6709 coordinate string.

Sign

Sign of a coordinate component.

Functions

parse

Parses an ISO 6709 coordinate string.