npm package: @mapbox/leaflet-omnivore
Description: a geospatial format parser for Leaflet
Author: Tom MacWright
Latest version: 0.3.4

# leaflet-omnivore

![](https://farm8.staticflickr.com/7373/12376158164_e335b4e61d_b.jpg)

[Leaflet](http://leafletjs.com/) supports the [GeoJSON](http://geojson.org/) format
by default. What if you have something else? That's where omnivore comes in.

It currently supports:

* [CSV](http://en.wikipedia.org/wiki/Comma-separated_values) (via [csv2geojson](https://github.com/mapbox/csv2geojson))
* GPX (via [toGeoJSON](https://github.com/mapbox/togeojson))
* [KML](http://developers.google.com/kml/documentation/) (via [toGeoJSON](https://github.com/mapbox/togeojson))
* [WKT](http://en.wikipedia.org/wiki/Well-known_text) (via [wellknown](https://github.com/mapbox/wellknown))
* [TopoJSON](https://github.com/mbostock/topojson)
* [Encoded Polylines](https://developers.google.com/maps/documentation/utilities/polylinealgorithm) via [polyline](https://github.com/mapbox/polyline)

Omnivore also includes an AJAX library, [corslite](https://github.com/mapbox/corslite),
so you can specify what you want to add to the map with just a URL.

## Installation

use it easily with the [Mapbox Plugins CDN](http://mapbox.com/mapbox.js/plugins/#leaflet-omnivore):

```html
<script src='//api.tiles.mapbox.com/mapbox.js/plugins/leaflet-omnivore/v0.3.1/leaflet-omnivore.min.js'></script>
```


Or download `leaflet-omnivore.min.js` from this repository.

## example

Live examples:

* [WKT](https://www.mapbox.com/mapbox.js/example/v1.0.0/omnivore-wkt/)
* [TopoJSON](https://www.mapbox.com/mapbox.js/example/v1.0.0/omnivore-topojson/)
* [Tooltips](https://www.mapbox.com/mapbox.js/example/v1.0.0/omnivore-kml-tooltip/)
* [KML](https://www.mapbox.com/mapbox.js/example/v1.0.0/omnivore-kml/)
* [GPX](https://www.mapbox.com/mapbox.js/example/v1.0.0/omnivore-gpx/)
* [Icons](https://www.mapbox.com/mapbox.js/example/v1.0.0/markers-from-csv-custom-style/)
* [CSV](https://www.mapbox.com/mapbox.js/example/v1.0.0/markers-from-csv/)

```js
var map = L.mapbox.map('map', 'mapbox.streets')
    .setView([38, -102.0], 5);

omnivore.csv('a.csv').addTo(map);
omnivore.gpx('a.gpx').addTo(map);
omnivore.kml('a.kml').addTo(map);
omnivore.wkt('a.wkt').addTo(map);
omnivore.topojson('a.topojson').addTo(map);
omnivore.geojson('a.geojson').addTo(map);
omnivore.polyline('a.txt').addTo(map);
```

## API

Arguments with `?` are optional. **parser_options** consists of options
sent to the parser library, _not_ to the layer: if you want to provide options
to the layer, see the example in the Custom Layers section.

By default, the library will construct a `L.geoJson()` layer internally and
call `.addData(geojson)` on it in order to load it full of GeoJSON. If you want
to use a different kind of layer, like a `L.mapbox.featureLayer()`, you can,
by passing it as `customLayer`, as long as it supports events and `addData()`.
You can also use this API to pass custom options to a `L.geoJson()` instance.:


* `.csv(url, parser_options?, customLayer?)`: Load & parse CSV, and return layer. Options are the same as [csv2geojson](https://github.com/mapbox/csv2geojson#api): `latfield, lonfield, delimiter`
* `.csv.parse(csvString, parser_options?)`: Parse CSV, and return layer.
* `.kml(url)`: Load & parse KML, and return layer.
* `.kml.parse(kmlString | gpxDom)`: Parse KML from a string of XML or XML DOM, and return layer.
* `.gpx(url, parser_options?, customLayer?)`: Load & parse GPX, and return layer.
* `.gpx.parse(gpxString | gpxDom)`: Parse GPX from a string of XML or XML DOM, and return layer.
* `.geojson(url, parser_options?, customLayer?)`: Load GeoJSON file at URL, parse GeoJSON, and return layer.
* `.wkt(url, parser_options?, customLayer?)`: Load & parse WKT, and return layer.
* `.wkt.parse(wktString)`: Parse WKT, and return layer.
* `.topojson(url, parser_options?, customLayer?)`: Load & parse TopoJSON, and return layer.
* `.topojson.parse(topojson)`: Parse TopoJSON (given as a string or object), and return layer.
* `.polyline(url, parser_options?, customLayer?)`: Load & parse polyline, and return layer.
* `.polyline.parse(txt, options, layer)`: Parse polyline (given as a string or object), and return layer.

Valid options:

#### polyline

* `precision` will change how the polyline is interpreted. By default, the value
  is 5. This is the [factor in the algorithm](https://developers.google.com/maps/documentation/utilities/polylinealgorithm),
  by default 1e5, which is adjustable.

### Custom Layers

Passing custom options:

```js
var customLayer = L.geoJson(null, {
    filter: function() {
        // my custom filter function
        return true;
    }
});

var myLayer = omnivore.csv('foo', null, customLayer);
```

Adding custom styles to a GeoJSON layer:

```js
var customLayer = L.geoJson(null, {
    // http://leafletjs.com/reference.html#geojson-style
    style: function(feature) {
        return { color: '#f00' };
    }
});
// this can be any kind of omnivore layer
var runLayer = omnivore.kml('line.kml', null, customLayer)
```

Using a `L.mapbox.featureLayer`:

```js
var layer = omnivore.gpx('a.gpx', null, L.mapbox.featureLayer());
```

### Async & Events

Each function returns an `L.geoJson` object. Functions that load from URLs
are **asynchronous**, so they will **not** immediately expose accurate `.setGeoJSON()` functions.

For this reason, we fire events:

* `ready`: fired when all data is loaded into the layer
* `error`: fired if data can't be loaded or parsed

```js
var layer = omnivore.gpx('a.gpx')
    .on('ready', function() {
        // when this is fired, the layer
        // is done being initialized
    })
    .on('error', function() {
        // fired if the layer can't be loaded over AJAX
        // or can't be parsed
    })
    .addTo(map);
```

`ready` does **not** fire if you don't use an asynchronous form of the function
like `.topojson.parse()`: because you don't need an event. Just run your code
after the call.

## Development

This is a [browserify](http://browserify.org/) project:

```sh
git clone git@github.com:mapbox/leaflet-omnivore.git

cd leaflet-omnivore

# to run tests
npm install

# to build leaflet-omnivore.js
npm run build
```

`leaflet-omnivore.js` and `leaflet-omnivore.min.js` are **built files** generated
from `index.js` by `browserify`. If you find an issue, it either needs to be
fixed in `index.js`, or in one of the libraries leaflet-omnivore uses
to parse formats.

## FAQ

* **What if I just want one format?** Lucky for you, each format is specified
  in a different module, so you can just use [TopoJSON](https://github.com/mbostock/topojson),
  [csv2geojson](https://github.com/mapbox/csv2geojson), [wellknown](https://github.com/mapbox/wellknown), or
  [toGeoJSON](https://github.com/mapbox/togeojson)
  individually.
* **My AJAX request is failing for a cross-domain request**. Read up on the [Same Origin Restriction](http://en.wikipedia.org/wiki/Same-origin_policy).
  By default, we use corslite, so cross-domain requests will try to use [CORS](http://en.wikipedia.org/wiki/Cross-origin_resource_sharing)
  if your server and browser supports it, but if one of them doesn't, there's no
  way on the internet to support your request.
* **Why isn't JSONP supported?** [Here's why](https://gist.github.com/tmcw/6244497).