utilities.md

Utilities

Coordinate conversion functions for GPS and local coordinates.

Import

from unetpy import to_gps, to_local

Coordinate conversion utilities for GPS and local coordinates.

This module provides functions to convert between GPS (latitude/longitude) coordinates and local Cartesian coordinates (meters). These functions mirror the coordinate math from unet.js.

Example:

    >>> from unetpy import to_gps, to_local
    >>> origin = (1.34286, 103.84109)  # lat, lon
    >>> lat, lon = to_gps(origin, x=100, y=100)
    >>> x, y = to_local(origin, lat, lon)

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to_gps

to_gps(origin: 'Sequence[float]', x: 'float', y: 'float') -> 'Tuple[float, float]'

Convert local coordinates (meters) to GPS coordinates.

Converts a point specified in meters from an origin point to GPS latitude/longitude coordinates.

Parameters:

Parameter	Description
origin	Origin point as (latitude, longitude) in degrees.
x	East-west displacement in meters (positive = east).
y	North-south displacement in meters (positive = north).

Returns:

Tuple of (latitude, longitude) in degrees. 

Example:

    >>> origin = (1.34286, 103.84109)
    >>> lat, lon = to_gps(origin, x=100, y=100)
    >>> print(f"{lat:.6f}, {lon:.6f}")
    1.343764, 103.841988

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to_local

to_local(origin: 'Sequence[float]', lat: 'float', lon: 'float') -> 'Tuple[float, float]'

Convert GPS coordinates to local coordinates (meters).

Converts a GPS point to meters displacement from an origin point.

Parameters:

Parameter	Description
origin	Origin point as (latitude, longitude) in degrees.
lat	Latitude of the point to convert in degrees.
lon	Longitude of the point to convert in degrees.

Returns:

Tuple of (x, y) displacement in meters from the origin.     x is east-west (positive = east), y is north-south (positive = north). 

Example:

    >>> origin = (1.34286, 103.84109)
    >>> x, y = to_local(origin, lat=1.343764, lon=103.841988)
    >>> print(f"{x:.1f}, {y:.1f}")
    99.9, 100.0

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