arcgis-rest-query 0.0.6

A tool to download a layer from an ArcGIS web service as GeoJSON

# ArcGIS REST Query

A simple library that can download a layer from a map in an ArcGIS web service and convert it to something useful, like GeoJSON.

## Usage

`python >>> import arcgis >>> source = "http://services.arcgis.com/P3ePLMYs2RVChkJx/ArcGIS/rest/services/USA_Congressional_Districts/FeatureServer" >>> arc = arcgis.ArcGIS(source) >>> layer_id = 0 >>> shapes = arc.get(layer_id, "STATE_ABBR='IN'") `

This assumes you’ve inspected your ArcGIS services endpoint to know what to look for. ArcGIS DOES publish json files enumerating the endpoints you can query, so autodiscovery could be possible further down the line.

## Installation

The easitest way: `bash pip install arcgis-rest-query ` From source:

`bash # Create a virtual environment (pip install virtualenv if you don't have it already) virtualenv python-arcgis-rest-query cd python-arcgis-rest-query . bin/activate git clone [e-mail]:Schwanksta/python-arcgis-rest-query repo cd repo pip install -r requirements.txt `

## From the command line

You can also use the included arcgis-get utility, like so:

Note: this query will take a long time, so maybe try one of the other examples below? `bash arcgis-get http://tigerweb.geo.census.gov/arcgis/rest/services/Basemaps/CommunityTIGER/MapServer 9 > ~/Desktop/railroads.geojson `

This will download a Railroads layer from the US Census’ TIGER dataset.

The size of that file brings up a good point: you should run –count_only before downloading an entire dataset, so you can see what you’re in store for.

`bash $ arcgis-get http://tigerweb.geo.census.gov/arcgis/rest/services/Basemaps/CommunityTIGER/MapServer 9 --count_only 182149 ` Since we go in batches of 1,000, you’re in for over 180 queries to the API.

## Piping to geojsonio

If you install [geojsonio-cli](https://github.com/mapbox/geojsonio-cli/), you can pipe output directly to a viewable map.

`bash npm install -g geojsonio-cli `

Then, we could re-do the previous query:

`bash arcgis-get http://tigerweb.geo.census.gov/arcgis/rest/services/Basemaps/CommunityTIGER/MapServer 9 | geojsonio `

And get some glorious mapped output: 

You can also do WHERE filtering from the command line. For example, if you want to get the Census’ state shape for just Florida and display it on geojson.io, you could do:

`bash arcgis-get --where="NAME = 'Florida'" http://tigerweb.geo.census.gov/arcgis/rest/services/Basemaps/CommunityTIGER/MapServer 28 | geojsonio ` 

## Potential pitfalls:

Since you can only query in batches of 1,000, and sometimes these are millions of records, these operations could take a long time. Currently there’s no status indicator on the CLI, so run –count_only first to see how long you might wait.