# shp-to-gltf

shp-to-gltf  is a javascript lib use to convert SHP(shapefile) to gltf(glb).

**Read this in other languages: [English](README.md), [中文](README_ZH.md).**
![polygon](https://wangchuan12.github.io/shpGltf/polygon.png)

## How to use

```js
npm install shp-to-gltf -g
```

```
shp-to-gltf  -i ./data/polygon.zip  -o ./data/b.glb  -f Elevation -c true -s color.json
```

## params

| -i     | input file path that file path is a shp file must a zip file |
| ------ | ------------------------------------------------------------ |
| **-o** | **output file path**                                         |
| **-c** | **set model center to origin true is to origin false is not** |
| **-f** | **set model extrude height by shp field**                    |
| **-d** | **use draco compress model true is use false is not**        |
| **-s** | **style file path is a json a file use to render per feature** |
| **-h** | **show help**                                                |
| **-g** | **It is used to group the output of elements.**             |

### style file 

```js
{
    "filed" : "Elevation", // filed is use to compute style
    "style" : [
        // this item mean when the feature propert of Elevation biger than range[0] and small range[1] render this color
        {    
            "range": [
                0,
                10
            ],
            "color": "rgb(253 , 215,154)"
        },
       
        {
            "range": [
                180,
                190
            ],
            "color": "rgb(25 , 84,123)"
        },
        {
            "range": [
                290,
                300
            ],
            "color": "rgb(25 , 84,123)"
        }
    ],
    "defaultColor" : "rgb(25 , 84,123)" // Render the default color when no style is hit
}
```
# Used in browser

```html
<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>shp</title>
</head>
<body>
    <h1 id="conent">ss</h1>
    <script type="module">
        import {ShpParse} from 'shp-to-gltf' 

        const h1 = document.getElementById('conent')
        // Get style file
        const getColorJson = async ()=>{
            const color = await fetch('./data/color.json')
            return await color.json()
        }
        
        // download
        const download = (data)=>{
            const blob = new Blob([data])
            const url = URL.createObjectURL(blob)
            const a = document.createElement('a')
            a.addEventListener
            a.href = url
            a.download = 'test.glb'
            a.click()
        }

        const shp = new ShpParse()

        const json = await getColorJson()
        
        // Set the style output for the shp object
        shp.setColorJson(json)
        
        const option = {
            height : 'Elevation', // Height field
            center : true, // The origin of the output is set to (0, 0, 0)
        }
        // Parse shp files to glb
        const data = await shp.parseWithUrl('./data/polygon.zip' , option)
        download(data)

    </script>
</body>
</html>
```

# Used in node

```js
import {ShpParse} from 'shp-to-gltf' 
const shpParse = new ShpParse()

// Set the style output for the shp object
const config = fs.readFileSync('./data/color.json')
shpParse.setColorJson(JSON.parse(config))

const dir = ['test1.zip' , 'test2.zip']
for (let i = 0 ; i < dir.length ; i++) {
    const item = dir[i]
    if (item.search('.zip') === -1) continue
    // Get the shp file
    const data = fs.readFileSync(item)
    // Parse shp files to glb
    const glb = await shpParse.parseWithBuffer(data , {
        height : 'Elevation',
        center : true,
        chunk : 100000 // More than 10000 elements of a single glb file are grouped for output
    })
    if (Array.isArray(glb)) {
        glb.forEach(async (items , index)=>{
            const tem = Buffer.from(items)
            fs.writeFileSync(`test${index}.glb` , tem )
        })
    } else {
        const tem = Buffer.from(glb)
        fs.writeFileSync(`test$.glb` ,  tem)
    }
}
```

# api

## ShpParse

A class that parses shp files into gltf

### method

#### parseWithUrl

```js

    /**
     * 
     * @param {string} url 
     * @param {{height : string , center : boolean , chunk ?: number , outputType ?: string}} option
     *
     */
    async parseWithUrl(url , option)
   
```

| **url**           | **An address used to represent the shp file**                |
| ----------------- | ------------------------------------------------------------ |
| **option-height** | **Sets the field used to extrude the plane into the model, the value of this field will be set to the height of the 3D mode** |
| **option-center** | **Whether to set the center point of the model to (0,0,0)**  |
| **option-chunk**  | **The maximum number of elements per glb, beyond which it is automatically grouped** |



#### **parseWithBuffer**

```js
   /**
     * 
     * @param {ArrayBuffer} buffer 
     * @param {{height : string , center : boolean , chunk ?: number , outputType ?: string}} option 
     * 
     * 
     */
    async parseWithBuffer(buffer , option)
```

| **url**           | **A buffer used to represent the shp file**                  |
| ----------------- | ------------------------------------------------------------ |
| **option-height** | **Sets the field used to extrude the plane into the model, the value of this field will be set to the height of the 3D mode** |
| **option-center** | **Whether to set the center point of the model to (0,0,0)**  |
| **option-chunk**  | **The maximum number of elements per glb, beyond which it is automatically grouped** |

#### **setColorJson**

**The style used to set the output model. See Style file  above for the style rules**

```js
setColorJson(colors)
```
# **Pay attention**

**1 When your shp file is large, use the -g command to block the output, and specify the chunk attribute when using the api**