OpenCage Geocoding Using KNIME

A standard installation of KNIME does not come with a built in Geocoder node but it’s very easy to either install one or make your own.

KNIME has a page dedicated to Geo Nodes (https://www.knime.com/book/geo-nodes) using the Palladian Community Nodes that supports both MapQuest and Google.

But if you want to roll your own using another geocoding service it’s very easy.

OpenCage Geocoding API

OpenCage is a well known Geocoding API that has very reasonable pricing allowing you to test the service for free and paid plans starting at €45 per month for 10,000 requests per day. First you should sign up to the service and get an API key for the free trial plan.

Using my OpenCage component you can create a simple workflow as shown below. This example shown how easy it is to feed addresses, geocode and then present the results on a map colour coded by location.

Opening the OpenCage component shows the details. Essentially it’s three configuration nodes used for the input, a GET Request to connect to the OpenCage API and parsing and cleaning of the return data.

Node Configuration

The node has a few configuration options:

• API Key provided by OpenCage
• Field that contains the address information to Geocode
• Rate limit option in requests per second (dependant on your plan)

Node Output

The node will output all input data plus:

• Latitude
• Longitude
• Confidence Score
• HTTP Status Code
• OpenStreetMap link
• Address returned by OpenCage

An example out put looks like the table below.

Address	Status	confidence	lat	lng	url	name
735 S Figueroa Street, Suite 150 Los Angeles, CA 90017	200	9	33.866183	-118.2816171	https://www.openstreetmap.org/?mlat=33.86618&mlon=-118.28162#map=17/33.86618/-118.28162	South Figueroa Street, Los Angeles, CA 90248-4007, United States of America
865 Avenue of the Americas New York, NY 10001	200	9	40.7478596	-73.9894889	https://www.openstreetmap.org/?mlat=40.74786&mlon=-73.98949#map=17/40.74786/-73.98949	Nordstrom Rack, 865 6th Avenue, New York, NY 10001, United States of America
224B Colonie Center Albany, NY 12205	200	9	42.7065888	-73.8202512	https://www.openstreetmap.org/?mlat=42.70659&mlon=-73.82025#map=16/42.70659/-73.82025	Colonie Center, 224 Colonie Center, Colonie, NY 12205, United States of America
555 12th Street Northwest, Front 1 Washington D.C. 20004	200	7	38.8969674	-77.0272414	https://www.openstreetmap.org/?mlat=38.89697&mlon=-77.02724#map=17/38.89697/-77.02724	Crunch Fitness, 555 12th Street Northwest, Washington, DC 20004, United States of America

Using the Latitude/Longitude to Coordinate (from Palladian), Colour Manager and Map Renderer (from Palladian) it’s easy to plot the co-ordinates on a map by colour and add labels.

Creating components like this is a great way to wrap a complex process into a simple to use and re-usable node.