ags-stream

ags-stream

ags-stream creates a readable stream of GeoJSON Features from an ArcGIS Server instance. This can be useful for scraping records from any ArcGIS Server or any other ETL process.

ags-stream is currently used in fulcrum-ags-import to import ArcGIS Server records into Fulcrum and ags-shapefile to export shapefiles from ArcGIS Server instances.

Installation

npm install ags-stream

Usage

var AgsStream = require('ags-stream');
var agsStream = new AgsStream(<service_url>, <options>?)
 
agsStream.on('data', function (data) {
  // data is an array of GeoJSON features
  data.forEach(function (feature) {
    doWhatever(feature); // Add the feature to you database, write to file, whatever
  });
});
 
agsStream.on('error', function (error) {
  console.log('Oh boy, this happened: ', error);
});
 
agsStream.on('end', function () {
  console.log('All done.'); // There is no more data to read.
});

The service_url parameter represents a single layer in an ArcGIS Server map service. It should look something like http://gis-web.co.union.nc.us/arcgis/rest/services/PWGIS_Web/Operational_Layers/MapServer/5.

options is optional and accepts the following:

Option	Description	Default
chunkSize	The number of features to fetch per request to the AGS instance	50
where	The where clause for querying the service layer	'1=1' (all features)
outSR	The srid for the returned geometry	4326 (lat, lng)
qs	An object of query strings to append to the url. These will be url encoded automatically.	null