npm package: @sitna/shpjs
Description: A binary shapefile loader, for javascript. Not many caveats
Author: Calvin Metcalf
Latest version: 3.4.9

# Shapefile.js

If you are having encoding issues in internet explorer please include [this script](https://cdn.rawgit.com/calvinmetcalf/text-encoding/4aff951959085f74a5872aeed8d79ec95b6c74c3/lib/encoding-indexes.js) as well.

Redoing all of this in modern JS. Promises, Typed Arrays, other hipster things, I wouldn't say it's based on [RandomEtc's version](https://github.com/RandomEtc/shapefile-js) as much as inspired by it as there is 0 code shared and I really only read the binary ajax part of his (hence why my function has the same name, they are otherwise not related). My sources were:

- [wikipedia article](https://en.wikipedia.org/wiki/Shapefile)
- [ESRI white paper](http://www.esri.com/library/whitepapers/pdfs/shapefile.pdf)
- [This page on Xbase](http://www.clicketyclick.dk/databases/xbase/format/dbf.html)

## Demos

- [Countries/zipfile](http://calvinmetcalf.github.io/shapefile-js)
- [Google maps](http://calvinmetcalf.github.io/shapefile-js/site/map.html)
- [Local Zipfile](http://leaflet.calvinmetcalf.com)
- [Projected big with web workers](http://calvinmetcalf.github.io/shapefile-js/site/proj.html)
- [Projected small](http://calvinmetcalf.github.io/shapefile-js/site/proj-small.html)

## Usage

For use with [browserify](http://browserify.org/), [webpack](https://webpack.github.io/):

    npm install shpjs --save
    
Or include directly in your webpage from:

    https://unpkg.com/shpjs@latest/dist/shp.js

## API

Has a function `shp` which accepts a string which is the path the she shapefile minus the extension and returns a promise which resolves into geojson.

```javascript
	//for the shapefiles in the folder called 'files' with the name pandr.shp
	shp("files/pandr").then(function(geojson){
		//do something with your geojson
	});
```
or you can call it on a .zip file which contains the shapefile

```javascript
	//for the shapefiles in the files folder called pandr.shp
	shp("files/pandr.zip").then(function(geojson){
		//see bellow for whats here this internally call shp.parseZip()
	});
```

or if you got the zip some other way (like the [File API](https://developer.mozilla.org/en-US/docs/Web/API/File)) then with the arrayBuffer you can call

```javascript
shp(buffer).then(function(geojson){});
//or
shp.parseZip(buffer)->returns zip
```
If there is only one shp in the zipefile it returns geojson, if there are multiple then it will be an array.  All of the geojson objects have an extra key `fileName` the value of which is the
name of the shapefile minus the extension (I.E. the part of the name that's the same for all of them)

You could also load the arraybuffers seperately:

```javascript
shp.combine([shp.parseShp(shpBuffer, /*optional prj str*/),shp.parseDbf(dbfBuffer)]);
```

## Stick it in a worker

I used my library [catiline](http://catilinejs.com/) to parallelize the demos to do so I changed

```html
<script src='dist/shp.js'> </script>
<script>
	shp('files/shapeFile.zip').then(function(data){
		//do stuff with data
	});
</script>
```

to

```html
<script src='website/catiline.js'> </script>
<script>
	var worker = cw(function(base,cb){
		importScripts('dist/shp.js');
		shp(base).then(cb);
	});
	//worker can be called multiple times
	worker.data(cw.makeUrl('files/shapeFile.zip')).then(function(data){
		//do stuff with data
	});
</script>
```

to send the worker a buffer from the file api you'd do (I'm omitting where you include the catiline script)

```javascript
var worker = cw(function(data){
	importScripts('../dist/shp.js');
	return shp.parseZip(data);
});

worker.data(reader.result,[reader.result]).then(function(data){
	//do stuff with data
});
```

## Done

- Binary Ajax
- parsing the shp
- parse the dbf
- join em
- zip
- file api
- Some Projections
- More Projections

## to do

- check for geometry validity.
- Tests


## LICENSE
Main library MIT license, original version was less permissive but there is 0 code shared. Included libraries are under their respective lisenses which are:
- [JSZip](https://github.com/Stuk/jszip/) by @Stuk MIT or GPLv3
- [lie](https://github.com/calvinmetcalf/lie) by me and @RubenVerborgh MIT
- [setImmediate](https://github.com/NobleJS/setImmediate) by @NobleJS et al MIT
- [World Borders shapefile](http://thematicmapping.org/downloads/world_borders.php) is CC-BY-SA 3.0.
- Park and Ride shapefile is from [MassDOT](http://mass.gov/massdot) and is public domain.
- MA town boundaries from [MassGIS](http://www.mass.gov/anf/research-and-tech/it-serv-and-support/application-serv/office-of-geographic-information-massgis/) and is public domain
- NJ County Boundaries from [NJgin](https://njgin.state.nj.us/NJ_NJGINExplorer/index.jsp) and should be public domain.
- [Proj4js](https://github.com/proj4js/proj4js) by me et al MIT

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