https://github.com/maasglobal/seafarer

Taxicab metric on the sphere!
https://github.com/maasglobal/seafarer

distance distance-calculation geospatial manhattan-distance metric taxicab

Last synced: 28 days ago
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Taxicab metric on the sphere!

• Host: GitHub
• URL: https://github.com/maasglobal/seafarer
• Owner: maasglobal
• License: mit
• Created: 2019-12-20T09:02:26.000Z (about 5 years ago)
• Default Branch: master
• Last Pushed: 2022-12-08T03:21:12.000Z (about 2 years ago)
• Last Synced: 2024-07-14T16:58:29.180Z (5 months ago)
• Topics: distance, distance-calculation, geospatial, manhattan-distance, metric, taxicab
• Language: Python
• Size: 80.1 KB
• Stars: 1
• Watchers: 6
• Forks: 2
• Open Issues: 4
• Metadata Files:
  • Readme: README.md
  • License: LICENSE
  • Code of conduct: CODE_OF_CONDUCT.md

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README

        
# Seafarer ⛵

Taxicab metric on the sphere! Install via

```bash

pip install seafarer

```

This library calculates the "seafarer distance" between two points on Earth:

Travel parallel to latitude and longitude instead of "as the crow flies" –

like in the old days...

## Usage

Calculate the distance between Schwerin and Helsinki:

```python

from seafarer import seafarer_metric

schwerin = (53.629722, 11.414722) # (lat, lon)

helsinki = (60.170278, 24.952222)

seafarer_metric(schwerin, helsinki)

# 1474.7398906623202 kilometres

```

You can also obtain the result in different units:

```python

seafarer_metric(schwerin, helsinki, unit="mi")

# 916.3608837507956 miles

seafarer_metric(schwerin, helsinki, unit="ft")

# 4838385.468052049 feet

```

Seafarer is using the [haversine](https://github.com/mapado/haversine) library

under the hood and you can use their `Unit` directly:

```python

from haversine import Unit

seafarer_metric(schwerin, helsinki, unit=Unit.NAUTICAL_MILES)

# 796.2958366185961 nautical miles

```

## What is this? Why Seafarer?

On a 2-dimensional plane, the metric obtained when travelling along the axes

is known as [taxicab](https://en.wikipedia.org/wiki/Taxicab_geometry),

Manhattan, or L1 metric. What is the equivalent on a 3-dimensional sphere?

We calculate the distance when travelling along the grid of longitudinal and

latitudinal lines. When travelling from Schwerin (53°N 11°E) to Helsinki

(60°N 24°E) in the example above, there are two possiblities: travel via

53°N 24°E or 60°N 11°E. Unlike the 2D case, these two distances are

(generally) different, so we use the short one.

Before navigation improved to a sufficient degree, this is how ships were

sailing: parallel to the equator until they hit the target meridian, then

North or South to their final destination. Hence seafarer metric! ⛵