simplification 0.2.11

Fast linestring simplification using RDP or Visvalingam-Whyatt and a Rust binary

[](https://travis-ci.org/urschrei/simplification) [](https://ci.appveyor.com/project/urschrei/simplification/branch/master) [](https://coveralls.io/github/urschrei/simplification?branch=master)

# Simplification
Simplify a LineString using the [Ramer–Douglas–Peucker](https://en.wikipedia.org/wiki/Ramer–Douglas–Peucker_algorithm) or [Visvalingam-Whyatt](https://bost.ocks.org/mike/simplify/) algorithms


## Installation
`pip install simplification`
Please use a recent (>= 8.1.2) version of `pip`.

### Supported Python Versions
- Python 2.7
- Python 3.4
- Python 3.5
- Python 3.6

### Supported Platforms
- Linux (`manylinux1`-compatible)
- OS X
- Windows 32-bit / 64-bit

## Usage
```python
import numpy as np
from simplification.cutil import simplify_coords, simplify_coords_vw

# Using Ramer–Douglas–Peucker
coords = [
[0.0, 0.0],
[5.0, 4.0],
[11.0, 5.5],
[17.3, 3.2],
[27.8, 0.1]
]

# For RDP, Try an epsilon of 1.0 to start with. Other sensible values include 0.01, 0.001
simplified = simplify_coords(coords, 1.0)

# simplified is [[0.0, 0.0], [5.0, 4.0], [11.0, 5.5], [27.8, 0.1]]

# Using Visvalingam-Whyatt
# You can also pass numpy arrays, in which case you'll get numpy arrays back
coords_vw = np.array([
[5.0, 2.0],
[3.0, 8.0],
[6.0, 20.0],
[7.0, 25.0],
[10.0, 10.0]
])
simplified_vw = simplify_coords_vw(coords, 30.0)

# simplified_vw is [[5.0, 2.0], [7.0, 25.0], [10.0, 10.0]]
```

Passing empty and/or 1-element lists will return them unaltered.

## But I Want to Simplify Polylines
No problem; [Decode them to LineStrings](https://github.com/urschrei/pypolyline) first.

``` python
# pip install pypolyline before you do this
from pypolyline.cutil import decode_polyline
# an iterable of Google-encoded Polylines, so precision is 5. For OSRM &c., it's 6
decoded = (decode_polyline(line, 5) for line in polylines)
simplified = [simplify_coords(line, 1.0) for line in decoded]
```

## How it Works
FFI and a [Rust binary](https://github.com/urschrei/rdp)

## Is It Fast
I should think so.

## License
[MIT](license.txt)