mapc.shp-write-cgcs

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 install --save 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.

Example

var shpwrite = require('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

Contributors

• Nick Baugh [e-mail]