---
title: "DEMData | JavaScript maps SDK"
description: "Documentation for MapTiler SDK"
---

> For AI agents: a documentation index is available at [/llms.txt](https://docs.maptiler.com/llms.txt). Markdown versions of all pages are available by appending .md to any URL.

# Class DEMData

##### Index

### Constructors[](#constructors)

[constructor](#constructor)

### Properties[](#properties)

[baseShift](#baseshift) [blueFactor](#bluefactor) [data](#data) [dim](#dim) [greenFactor](#greenfactor) [max](#max) [min](#min) [redFactor](#redfactor) [stride](#stride) [uid](#uid)

### Methods[](#methods)

[backfillBorder](#backfillborder) [get](#get) [getPixels](#getpixels) [getUnpackVector](#getunpackvector) [pack](#pack) [unpack](#unpack)

## Constructors[](#constructors-1)

### constructor[](#constructor)

-   new DEMData(  
        uid: string | number,  
        data: [RGBAImage](https://docs.maptiler.com/sdk-js/api-reference/classes/Externals.RGBAImage/) | [ImageData](https://docs.maptiler.com/sdk-js/api-reference/interfaces/Externals.ImageData/),  
        encoding: [DEMEncoding](https://docs.maptiler.com/sdk-js/api-reference/types/Externals.DEMEncoding/),  
        redFactor?: number,  
        greenFactor?: number,  
        blueFactor?: number,  
        baseShift?: number,  
    ): DEMData[](#constructordemdata)
    
    Constructs a `DEMData` object
    
    #### Parameters
    
    -   uid: string | number
        
        the tile's unique id
        
    -   data: [RGBAImage](https://docs.maptiler.com/sdk-js/api-reference/classes/Externals.RGBAImage/) | [ImageData](https://docs.maptiler.com/sdk-js/api-reference/interfaces/Externals.ImageData/)
        
        RGBAImage data has uniform 1px padding on all sides: square tile edge size defines stride // and dim is calculated as stride - 2.
        
    -   encoding: [DEMEncoding](https://docs.maptiler.com/sdk-js/api-reference/types/Externals.DEMEncoding/)
        
        the encoding type of the data
        
    -   `Optional`redFactor: number
        
        the red channel factor used to unpack the data, used for `custom` encoding only
        
    -   `Optional`greenFactor: number
        
        the green channel factor used to unpack the data, used for `custom` encoding only
        
    -   `Optional`blueFactor: number
        
        the blue channel factor used to unpack the data, used for `custom` encoding only
        
    -   `Optional`baseShift: number
        
        the base shift used to unpack the data, used for `custom` encoding only
        
    
    #### Returns DEMData
    

## Properties[](#properties-1)

### baseShift[](#baseshift)

baseShift: number

### blueFactor[](#bluefactor)

blueFactor: number

### data[](#data)

data: Uint32Array

### dim[](#dim)

dim: number

### greenFactor[](#greenfactor)

greenFactor: number

### max[](#max)

max: number

### min[](#min)

min: number

### redFactor[](#redfactor)

redFactor: number

### stride[](#stride)

stride: number

### uid[](#uid)

uid: string | number

## Methods[](#methods-1)

### backfillBorder[](#backfillborder)

-   backfillBorder(borderTile: DEMData, dx: number, dy: number): void[](#backfillborder-1)
    
    #### Parameters
    
    -   borderTile: DEMData
    -   dx: number
    -   dy: number
    
    #### Returns void
    

### get[](#get)

-   get(x: number, y: number): number[](#get-1)
    
    #### Parameters
    
    -   x: number
    -   y: number
    
    #### Returns number
    

### getPixels[](#getpixels)

-   getPixels(): [RGBAImage](https://docs.maptiler.com/sdk-js/api-reference/classes/Externals.RGBAImage/)[](#getpixels-1)
    
    #### Returns [RGBAImage](https://docs.maptiler.com/sdk-js/api-reference/classes/Externals.RGBAImage/)
    

### getUnpackVector[](#getunpackvector)

-   getUnpackVector(): number\[\][](#getunpackvector-1)
    
    #### Returns number\[\]
    

### pack[](#pack)

-   pack(v: number): { b: number; g: number; r: number }[](#pack-1)
    
    #### Parameters
    
    -   v: number
    
    #### Returns { b: number; g: number; r: number }
    

### unpack[](#unpack)

-   unpack(r: number, g: number, b: number): number[](#unpack-1)
    
    #### Parameters
    
    -   r: number
    -   g: number
    -   b: number
    
    #### Returns number