Usage in Browser
Relevant source files
The following files were used as context for generating this wiki page:
The geo-path-reducer module is designed to simplify complex geographical paths using the Douglas-Peucker algorithm. In a browser environment, this allows developers to optimize the rendering of spatial data (such as GPS tracks or map boundaries) by reducing the number of points while maintaining the path's essential shape.
The implementation is provided as a modern JavaScript module, utilizing ES6 export syntax. It operates on standard JavaScript objects representing geographic coordinates, making it compatible with most front-end mapping libraries.
Sources: README.md:1-5, package.json:11
Integration and Setup
To use the module in a browser project, it must be integrated via a module-aware environment. The package is configured as an ES module, which is the standard for modern browser-side development.
Installation and Import
The library is distributed via npm and can be imported into a project's source code. Because the package.json specifies "type": "module", it is intended for use with build tools like Webpack or Vite, or directly in browsers that support <script type="module">.
import geoPathReducer from 'geo-path-reducer';
Sources: package.json:11, README.md:16
Core Algorithm Logic
The browser-side implementation relies on a recursive application of the Douglas-Peucker algorithm. It evaluates the perpendicular distance of intermediate points from a line segment connecting the start and end points of a path.
Process Flow
The following diagram illustrates the logical flow when geoPathReducer is called:
The algorithm determines which points are significant enough to keep based on the epsilon threshold.
Sources: src/index.js:3-23
Mathematical Components
The reduction relies on two underlying utility modules to perform geographical calculations:
- Great-Circle Distance: Calculated in
distance.jsusing the Earth's radius (6371 km). It computes the distance between two points on a sphere. - Perpendicular Distance: Calculated in
perpendicular-distance.js. It uses the Heron's formula equivalent (via semi-perimetersandarea) to find the distance from a point to the line segment formed by the path's boundaries.
API Reference
The browser-accessible API consists of a single default export function.
Main Function: geoPathReducer(points, epsilon)
| Parameter | Type | Description |
|---|---|---|
points | Array | An array of objects, where each object contains lat and lng properties. |
epsilon | Number | The maximum distance threshold. If a point's distance from the line is less than this, it may be removed. |
Return Value: A new array of simplified point objects { lat, lng }.
Sources: README.md:29-38, src/index.js:3
Data Structures
The library expects and returns points in the following format:
{
"lat": 37.7749,
"lng": -122.4194
}
Sources: README.md:21-25
Sequence of Operations
When a browser application requests a path reduction, the following sequence occurs between the module's internal components:
Summary
Usage in the browser involves importing the geoPathReducer ES module and passing an array of geographical coordinates. The module efficiently reduces path complexity by recursively identifying points that deviate significantly from the path's trajectory, using a Great-Circle distance model for accuracy. This is highly effective for improving the performance of web-based mapping applications.