https://github.com/hongfaqiu/cgcsfile2json

convert cgcs2000 polygon shp or txt to geojson
https://github.com/hongfaqiu/cgcsfile2json

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convert cgcs2000 polygon shp or txt to geojson

• Host: GitHub
• URL: https://github.com/hongfaqiu/cgcsfile2json
• Owner: hongfaqiu
• Created: 2021-06-01T07:53:46.000Z (over 3 years ago)
• Default Branch: main
• Last Pushed: 2021-06-04T08:52:45.000Z (over 3 years ago)
• Last Synced: 2024-12-31T09:41:44.644Z (12 days ago)
• Language: JavaScript
• Size: 14.6 KB
• Stars: 1
• Watchers: 1
• Forks: 4
• Open Issues: 0
• Metadata Files:
  • Readme: README.md

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README

        
# cgcsfile2json

convert cgcs2000(4528, 4549, 4490) polygon shp or txt to CGCS_2000(EPSG:4490) geojson

代码写得很烂，凑活用吧，后面有空再重构

## usage

For node.js

    npm install --save cgcsfile2json

## example

```js

import file2coor from 'cgcsfile2json'

let txtFile = getFile('test.txt');

let coors = file2coor.getCoordinates();

// coors: [4528, 4549, 4490];

// coorsCh: ['大地2000 有带号直角坐标系', '大地2000 无带号直角坐标系', '大地2000经纬度坐标系']

// txt's coordinate defalut is '大地2000 有带号直角坐标系'

let data = file2coor.convertFile(txtFile, 'txt'); 

let shpFile = getFile('test.shp');

let data2 = file2coor.convertFile(shpFile, 'shp', coors[2]); 

```

## API

### ``getCoordinates()``

[4528, 4549, 4490]

### ``convertFile(file, type, coor = 4528)``

convert .shp or .txt file to geojson

### ``boundCheck(data, order = false)``

check if the geojson data is out of bounds

when 'order' value is true, representes the point's coordinates is [lat, lon], otherwise defalut is [lon, lat]

### ``setBoundary(bound)``

defalut boundary is:  

```js

{ // 杭州范围

  xMin: 118.1217,

  xMax: 120.7753,

  yMin: 29.1304,

  yMax: 30.6191

}

```

### ``judgeTypeByName(file, type)``

judge the file(shp or txt)'s coordinates, txt file is 4528('大地2000 有带号直角坐标系').

The coordinate system of SHP file will be judged by whether the converted data exceeds the set boundary

### ``parsingShape(file)``

parse the shp file to geojson

```js

parsingShape(file).then(res => {

  console.log(res);

})

```

### ``handleDataChange(data, coor, precise = true)``

convert the data to CGCS_2000(EPSG:4490) geojson

when precise param is false, use the offline algorithm, which can only be accurate to the seven decimal place.

defalut chose the online algorithm provided by [arcgis server](https://sampleserver6.arcgisonline.com/arcgis/rest/services/Utilities/Geometry/GeometryServer/project).

### ``xy2lonlat(X, Y, L0)``

convert cscs2000(XYZ) point to cscs2000(BLH)