[−][src]Crate flexpolyline
Flexible Polyline encoding
The flexible polyline encoding is a lossy compressed representation of a list of coordinate pairs or coordinate triples. It achieves that by:
- Reducing the decimal digits of each value.
- Encoding only the offset from the previous point.
- Using variable length for each coordinate delta.
- Using 64 URL-safe characters to display the result.
The encoding is a variant of Encoded Polyline Algorithm Format. The advantage of this encoding over the original are the following:
- Output string is composed by only URL-safe characters, i.e. may be used without URL encoding as query parameters.
- Floating point precision is configurable: This allows to represent coordinates with precision up to microns (5 decimal places allow meter precision only).
- It allows to encode a 3rd dimension with a given precision, which may be a level, altitude, elevation or some other custom value.
Specification
See Specification.
Example
use flexpolyline::{Polyline, Precision}; // encode let coordinates = vec![ (50.1022829, 8.6982122), (50.1020076, 8.6956695), (50.1006313, 8.6914960), (50.0987800, 8.6875156), ]; let polyline = Polyline::Data2d { coordinates, precision2d: Precision::Digits5, }; let encoded = polyline.encode().unwrap(); assert_eq!(encoded, "BFoz5xJ67i1B1B7PzIhaxL7Y"); // decode let decoded = Polyline::decode("BFoz5xJ67i1B1B7PzIhaxL7Y").unwrap(); assert_eq!( decoded, Polyline::Data2d { coordinates: vec![ (50.10228, 8.69821), (50.10201, 8.69567), (50.10063, 8.69150), (50.09878, 8.68752) ], precision2d: Precision::Digits5 } );Run
Enums
Error | Error reported when encoding or decoding polylines |
Polyline | 2- or 3-dimensional polyline |
Precision | Coordinate precision in the polyline |
Type3d | Informs about the type of the 3rd dimension of a 3D coordinate vector |