@aleffabricio/shp-write

shp-write

Writes shapefile in pure javascript. Uses dbf for the data component, and jsZIP to generate ZIP file downloads in-browser.

Usage

For node.js or browserify

npm i @aleffabricio/shp-write

Or in a browser

https://unpkg.com/shp-write@latest/shpwrite.js

Caveats

• Requires a capable fancy modern browser with Typed Arrays support
• Geometries: Point, LineString, Polygon, MultiLineString, MultiPolygon
• Tabular-style properties export with Shapefile's field name length limit
• Uses jsZip for ZIP files, but compression is buggy so it uses STORE instead of DEFLATE.

Polygon example

var shpwrite = require('@aleffabricio/shp-write');

var options = {
        folder: "my-shapefile",
        types: {
            point: "points",
            polygon: "polygons",
            line: "lines"
        }
    }

// Projection: WGS84

var geojson = {
  "type": "FeatureCollection",
  "features": [
    {
      "type": "Feature",
      "properties": {
       
      },
      "geometry": {
        "type": "Polygon",
        "coordinates": [
          [
            [
              -5.467621768044272,
              36.64743275993502
            ],
            [
              -5.467616023377893,
              36.64725262371037
            ],
            [
              -5.467727794596266,
              36.647250311416094
            ],
            [
              -5.4677335449678175,
              36.64743044300626
            ],
            [
              -5.467621768044272,
              36.64743275993502
            ]
          ]
        ]
      }
    },
    {
      "type": "Feature",
      "properties": {
       
      },
      "geometry": {
        "type": "Polygon",
        "coordinates": [
          [
            [
              -5.468579574838962,
              36.64614919750399
            ],
            [
              -5.468677755266358,
              36.64598024036407
            ],
            [
              -5.468701623050998,
              36.64580090235523
            ],
            [
              -5.468830896750093,
              36.64567899650186
            ],
            [
              -5.468975712398754,
              36.64558061087395
            ],
            [
              -5.469122814442818,
              36.64555371740699
            ],
            [
              -5.469162767231621,
              36.645614168657936
            ],
            [
              -5.46917602392241,
              36.645613117730576
            ],
            [
              -5.4691850012488645,
              36.6456478100721
            ],
            [
              -5.46924794829598,
              36.645765734116225
            ],
            [
              -5.4692817042946,
              36.645896186275486
            ],
            [
              -5.469010322149157,
              36.646106416589326
            ],
            [
              -5.468930830984821,
              36.64609508166739
            ],
            [
              -5.468903730321685,
              36.646106711088834
            ],
            [
              -5.468579574838962,
              36.64614919750399
            ]
          ]
        ]
      }
    }
  ]
};

shpwrite.download(geojson, options);

Point example

var shpwrite = require('@aleffabricio/shp-write');

// (optional) set names for feature types and zipped folder
var options = {
    folder: 'myshapes',
    types: {
        point: 'mypoints',
        polygon: 'mypolygons',
        line: 'mylines'
    }
}
// a GeoJSON bridge for features
shpwrite.download({
    type: 'FeatureCollection',
    features: [
        {
            type: 'Feature',
            geometry: {
                type: 'Point',
                coordinates: [0, 0]
            },
            properties: {
                name: 'Foo'
            }
        },
        {
            type: 'Feature',
            geometry: {
                type: 'Point',
                coordinates: [0, 10]
            },
            properties: {
                name: 'Bar'
            }
        }
    ]
}, options);
// triggers a download of a zip file with shapefiles contained within.

API

download(geojson)

Given a GeoJSON FeatureCollection as an object, converts convertible features into Shapefiles and triggers a download.

write(data, geometrytype, geometries, callback)

Given data, an array of objects for each row of data, geometry, the OGC standard geometry type (like POINT), geometries, a list of geometries as bare coordinate arrays, generate a shapfile and call the callback with err and an object with

{
    shp: DataView(),
    shx: DataView(),
    dbf: DataView()
}

zip(geojson)

Generate a ArrayBuffer of a zipped shapefile, dbf, and prj, from a GeoJSON object.

Other Implementations

• https://code.google.com/p/pyshp/

Reference

• http://www.esri.com/library/whitepapers/pdfs/shapefile.pdf

Notes

• This project solves the bug that occurred when exporting a featureCollection with more than one polygon. He turned polygons into multipoligons. Because the project is not maintained by its creator I built a npm library based on the @jmmluna project

Contributors

• Nick Baugh [e-mail]