@maplat/tin NPM

Maplat Tin

A JavaScript library that defines and executes homeomorphic conversion between two plane coordinate systems based on control points.
This is part of the Maplat project.

日本語のREADMEはこちら

Key Features

Generate Transformation Definitions: Create coordinate transformation definitions based on control points and edge constraints
Bidirectional Coordinate Transformation: Convert coordinates between two planes in both directions
Topology Preservation: Maintains homeomorphic properties during transformation
Flexible Configuration:
- Vertex handling modes (normal/bird's-eye view)
- Topology check modes (strict/auto/loose)
- Y-axis direction control
Edge Constraints: Ability to specify constrained edges for more accurate transformation
State Management: Save and restore transformation definitions

Installation

npm

# Install the main package
npm install @maplat/tin

# Install required dependency
npm install delaunator

Browser

<!-- Required dependency -->
<script src="https://unpkg.com/delaunator/delaunator.min.js"></script>

<!-- Maplat Tin -->
<script src="https://unpkg.com/@maplat/tin/dist/maplat_tin.umd.js"></script>

Basic Usage

// Create a new instance with basic configuration
const tin = new Tin({
    wh: [500, 500],          // Width and height of the source plane
    yaxisMode: Tin.YAXIS_FOLLOW  // Y-axis direction handling
});

// Set control points: Array of [source, target] coordinates
tin.setPoints([
    [[100,100], [200, 200]], // Point 1
    [[200,200], [400, 400]], // Point 2
    [[150,150], [320, 350]], // Point 3
    [[200,100], [420, 220]]  // Point 4
]);

// Initialize the TIN network
tin.updateTin();

// Check topology status
if (tin.strict_status === Tin.STATUS_STRICT) {
    console.log('Topology OK: Roundtrip transform is guaranteed');
} else if (tin.strict_status === Tin.STATUS_LOOSE) {
    console.log('Topology warning: Roundtrip transform is not guaranteed');
}

// Forward transform: source to target
const transformed = tin.transform([160, 160], false);

// Backward transform: target to source
const restored = tin.transform(transformed, true);

Configuration

Constructor Options

Option	Type	Description	Default
`bounds`	`Position[]`	Boundary polygon vertices	`-`
`wh`	`number[]`	Width and height w, h	`-`
`vertexMode`	`"plain"｜"birdeye"`	Vertex handling mode	`"plain"`
`strictMode`	`"strict"｜"auto"｜"loose"`	Topology check mode	`"auto"`
`yaxisMode`	`"follow"｜"invert"`	Y-axis direction	`"invert"`
`importance`	`number`	Map importance	`0`
`priority`	`number`	Map priority	`0`

Either bounds or wh must be specified.

Methods

Method	Description
`setPoints(points)`	Set control points
`setEdges(edges)`	Set constrained edges
`updateTin()`	Initialize/update TIN network
`transform(coords, inverse)`	Execute coordinate transformation
`getCompiled()`	Get serializable state
`setCompiled(state)`	Restore from serialized state