We have just released the first beta of the Drupal OpenLayers module. It's been a pretty crazy adventure as to how we got here, and there are still high hopes for the future. This post is going to be a long one, and should give you the complete introduction to this new mapping module for Drupal, and will also build on and borrow from my previous post on building this module.

• Jump to Project Page
• Check out the Demo
• Read Documentation

What is OpenLayers?

OpenLayers is a free, open-source Javascript library that provides an easy interface to bring together any sort of map tiles, markers, features, and other GIS goodness. OpenLayers was initially developed by MetaCarta; it is now a project of the Open Source Geospatial Foundation. Think Google Maps but open-source. The OpenLayers has many examples and a gallery of sites.

Where Drupal Fits In

Drupal is a great content management system and development framework. OpenLayers fits well into this because it basically is a really great visualization tool for content (the most obvious visualization being maps). Drupal can provide the ability to create and management data/content and OpenLayers can be a fun vehicle to displaying that content and provide a rich interface for your users.

Main Features and Modules

The Drupal OpenLayers module is actually a full suite of modules that provide many integration points with other contributed modules.

• At is core, the OpenLayers API module provides just enough to take a map array in PHP and render it through hooks, pass it to javascript where it can interact with events, and display a working map to the page. The main API module also manages the basics of map presets.
• The OpenLayers Preset User Interface module provides a web based interface to manage presets. Presets are basically just named map arrays that are either stored in code or in the database. With presets it becomes easy to provide interfaces to pick maps.
• OpenLayers Layers modules provides a wide range of layers to use outside the simple default, like Yahoo, Google, OpenStreetMap tiles, and more. Layers can be manually put into map arrays, but with hooks, other modules can provided named layers that get put together when the map is rendered.
• Much like the layers module, the OpenLayers Behaviors module provides a set of behavior add-ons that can easily be added to map arrays. These include things like feature controls, fullscreen controls, popups, and tooltips.
• On the input side, there is the OpenLayers CCK module which provides integration with OpenLayers and CCK. This module provides a field and widget for basic WKT input, as well as a widget for the Geo module; both of which allow the user to use a map to enter features like points, lines, and polygons. On the formatter side, you can display any preset map for the field.
• A simple way to display a map is to use the OpenLayers Filter module, which provides an input format filter where a user can input [openlayers preset_name] into the body content of a node and it will be rendered as that map.
• Finally, there is a Views plugin provided by the OpenLayers Views module that allows the user to aggregate all kinds of Drupal data and put it into a map.

June 2009 is Geo June, which is a campaign to organized by Advantage Labs to make a concentrated effort to stabilize the Geo Module and push towards Drupal as a GeoCMS.

What is Geo and Why is it Useful?

Geo is mainly a storage layer to hold geospatial data. What does that mean? Well, we all know about points such as latitude and longitude, but Geo helps to store other data such as lines and polygons.

Geo standardizes how all this data is stored, which is extremely helpful for modules, such as Location to store data and have the heavy lifting done for it, and makes it easy for modules such as Gmap, NIceMap, and Mapstraction to easily retrieve and display that data in lots of fun ways. Geo also provides a database abstraction layer to work with both PostGIS and MySQL Spatial.

Still not convinced of it's awesomeness, well then think Mashups! Though I am not a fan of the term, Map Mashups are all the rage and for good reason (data visualization is a great way to communicate large sets of data). By standardizing Drupal's GIS storage, it will be exponentially easier to integrate (i.e. mashup) data from your site with all those exciting external sources of data. Don't think you can collect geospatial data? Think again, more interweb explorers are becoming a lot more spatially aware and want their data represented in the context of our world. And even with lots of new open data, there are still lots of reasons to store that spatial data directly on your site.

There are many other use cases at this wiki page (feel free to add).

Events and Getting Involved

If you are interested in getting involved, go here. Some of the events going on or ways to participate:

• Geo June Kickoff Barbecue, June 1: A decidedly offline event in Minneapolis
• Join the daily IRC Meetups, June 1-30 : Meet in #drupal-geo from 10AM-11AM CST
• Blog in June about Drupal geo projects and Drupal as a GeoCMS
• Participate in the community.
• Participate in the TC Drupal Documentation Sprint. June 20
• Organize other events locally or online, dealing with any type of Mapping or Geospatial activities in Drupal.
• Contribute financially
• Join us at the release party! June 30

OpenLayers

Another goal of Geo June is for the OpenLayers Drupal Module to release a 1.0 (though I would be happy with a beta, personally). We have been really busy developing this module. It's fairly stable at the moment, but needs lots of cleaning up. We welcome testing and reporting bugs.

The Future

Drupal has always been good at being current with new technologies and this is an opportunity to continue that tradition. Geo is the building block for realizing Drupal as a GeoCMS, meaning that Drupal can consume, produce, collect, aggregate, display, cuddle, and mash geospatial data in a user-friendly (and developer-friendly) way. I personally don't know of anything that can currently be compared as a GeoCMS, and even with a stable Geo, we still have a long way to go, but I would love to see Drupal be the first GeoCMS.

Last week, I ended up at the Twin Cities (Minneapolis and Saint Paul, Minnesota, USA twin cities) MapServer User Group and Twin Cities Open Source Geo Chapter. After Googling for a little bit, I did not find any good examples, but from what I understand GIS and Minnesota have a rich history. Anyway, the meeting was great. Reid Priedhorsky, a computer science graduate student at the University of Minnesota, came by to give a presentation on Cyclopath, for which he is a project manager.

What is a Geo-Wiki?

Well, a wiki, in the computer world is usually a web application that can be easily edited by a large audience. It usually means that the users of the site, have control over what content is on the site. Wikipedia is the largest and most successful example.

The term geowiki is a fairly new concept; in fact it was new to me, just until last week. But the idea is pretty straightforward; it brings together the idea of a wiki and applies it to a map (or other GIS). This means that a map, more specifically, it's features becomes easily editable to a large audience. For instance, you can add a new street, or note a really nice view.

The most widely known and used geowiki may be Open Street Map,

What is Cyclopath?

Cyclopath is a geowiki geared towards bicycling in the Twin Cities area, and is being built by GroupLens Research, a research group at the University of Minnesota. It allows anyone to edit the features on a map of the Twin Cities. Yes, anyone!