@nsc-earth-2/measure

@nsc-earth-2/measure is a measurement tool based on Cesium, which supports distance and area measurement and is easy to use. 中文 Readme

Installation

Install via npm:

npm install @nsc-earth-2/measure --save

Usage

Import the @nsc-earth-2/measure module in your project, then instantiate the corresponding measuring class for measurement.

AreaMeasure

Used for non-ground area measurement.

import { Viewer } from "cesium";
import { AreaMeasure } from "@nsc-earth-2/measure";

const viewer = new Viewer("cesiumContainer");
const areaMeasure = new AreaMeasure(viewer, {
  onEnd: (entity) => {
    console.log(entity); // The callback function when the measurement is completed, returning the measurement result
  },
});

// Start drawing
areaMeasure.start();

AreaSurfaceMeasure

Used for ground area measurement.

import { Viewer } from "cesium";
import { AreaSurfaceMeasure } from "@nsc-earth-2/measure";

const viewer = new Viewer("cesiumContainer");
const areaSurfaceMeasure = new AreaSurfaceMeasure(viewer, {
  onEnd: (entity) => {
    console.log(entity); // The callback function when the measurement is completed, returning the measurement result
  },
});

// Start drawing
areaSurfaceMeasure.start();

DistanceMeasure

Used for non-ground distance measurement.

import { Viewer } from "cesium";
import { DistanceMeasure } from "@nsc-earth-2/measure";

const viewer = new Viewer("cesiumContainer");
const distanceMeasure = new DistanceMeasure(viewer, {
  onEnd: (entity) => {
    console.log(entity); // The callback function when the measurement is completed, returning the measurement result
  },
});

// Start drawing
distanceMeasure.start();

DistanceSurfaceMeasure

Used for ground distance measurement.

import { Viewer } from "cesium";
import { DistanceSurfaceMeasure } from "@nsc-earth-2/measure";

const viewer = new Viewer("cesiumContainer");
const distanceSurfaceMeasure = new DistanceSurfaceMeasure(viewer, {
  onEnd: (entity) => {
    console.log(entity); // The callback function when the measurement is completed, returning the measurement result
  },
});

// Start drawing
distanceSurfaceMeasure.start();

API

MeasureOptions

| Parameter | Type | Description | | ------------- | -------- | --------------------------------------------------- | | labelStyle | object | Label style | | units | string | Unit of measure, default is 'kilometers' | | locale | object | Custom locale | | onEnd | function | Callback function when the measurement is completed | | drawerOptions | object | Drawing tool options |

Measure

The base class for measurement. Other measuring classes inherit from this class.

Constructor

constructor(viewer: Viewer, options?: MeasureOptions)

Create a measurement tool instance.

Parameters:

• viewer: Cesium.Viewer object.
• options (optional): Configuration item with type MeasureOptions.

Properties

destroyed: boolean

Returns whether the current measurement tool has been destroyed.

mouseTooltip: MouseTooltip

Mouse tooltip tool instance.

drawer: Drawer

Drawing tool instance.

Methods

start(): void

Start measuring.

end(): void

End measuring and clear the measurement result.

destroy(): void

Destroy the measurement tool.

AreaMeasure

Used for non-ground area measurement.

Constructor

constructor(viewer: Viewer, options?: MeasureOptions)

Create an AreaMeasure instance.

Parameters:

• viewer: Cesium.Viewer object.
• options (optional): Configuration item with type MeasureOptions.

Methods

getArea(positions: Cartesian3[]): number

Calculate the area of a polygon.

Parameters:

• positions: An array of positions, with each position being of type Cartesian3.

Return value: The area, with the unit specified by the configuration item, defaulting to meters.

AreaSurfaceMeasure

Used for ground area measurement.

Constructor

constructor(viewer: Viewer, options?: MeasureOptions)

Create an AreaSurfaceMeasure instance.

Parameters:

• viewer: Cesium.Viewer object.
• options (optional): Configuration item with type MeasureOptions.

Methods

getArea(positions: Cartesian3[]): number

Calculate the ground area of a polygon.

Parameters:

• positions: An array of positions, with each position being of type Cartesian3.

Return value: The area, with the unit specified by the configuration item, defaulting to meters.

DistanceMeasure

Used for non-ground distance measurement.

Constructor

constructor(viewer: Viewer, options?: MeasureOptions)

Create a DistanceMeasure instance.

Parameters:

• viewer: Cesium.Viewer object.
• options (optional): Configuration item with type MeasureOptions.

Methods

getDistance(start: Cartesian3, end: Cartesian3): number

Calculate the distance between two points.

Parameters:

• start: The starting point coordinates, as a Cartesian3.
• end: The ending point coordinates, as a Cartesian3.

Return value: The distance between the two points, with the unit specified by the configuration item, defaulting to meters.

DistanceSurfaceMeasure

Used for ground distance measurement.

Constructor

constructor(viewer: Viewer, options?: MeasureOptions & {splitNum?: number})

Create a DistanceSurfaceMeasure instance.

Parameters:

• viewer: Cesium.Viewer object.
• options (optional): Configuration item with type MeasureOptions, also supports an additional splitNum parameter, indicating how many segments to divide the line for surface distance calculation. When this parameter is not passed, it defaults to 10.

Methods

getDistance(pos1: Cartesian3, pos2: Cartesian3): number

Calculate the ground distance between two points.

Parameters:

• pos1: The starting point coordinates, as a Cartesian3.
• pos2: The ending point coordinates, as a Cartesian3.

Return value: The distance between the two points, with the unit specified by the configuration item, defaulting to meters.

Notes

• This tool is based on Cesium and requires the Cesium library to be imported into the project.
• Please make sure you understand the basics of Cesium and how to create a Viewer before using the measuring tool.
• Before using the measuring tool, other operations that may affect the interaction, such as camera roaming and scene rotation, should be stopped.
• Please be aware of the performance of the browser during use. Excessive drawing may cause the browser to crash or freeze.
• The current version only supports distance and area measurement. If you need to implement other functions, you can extend it yourself.
• The tool code is open source. If you have any questions or suggestions, please submit an issue or PR on the GitHub project page.