O'Reilly Network Weblogs: Mapping Hurricane Frances Online

Published on The O'Reilly Network (http://www.oreillynet.com/)
http://www.oreillynet.com/pub/wlg/5542

Mapping Hurricane Frances Online

by Tyler Mitchell
Sep. 3, 2004
URL: http://spatialguru.com/maps/apps/global/

I started the above linked website in order to experiment with open web mapping standards. There has been a lot of talk about Open GIS Consortium standards of late, so I decided to make my own global web map using some of the map data available through these Internet standards. It's nothing fancy to look at, but how data behind it comes together is very intriguing. Any time I find a new data source that may be interesting to look at, I add it to my growing list of layers. Which brings me to Hurricane Frances.

Earlier today I received an email pointing me to a web map showing a current (updated every 6 hours) track of Hurricane Frances. Because the developers of the site (DM Solutions) implement open web mapping standards, I knew I'd probably be able to access the same data source they did for their track of Frances. Sure enough, I looked at their map credits page and found the reference I was after:

Hurricane Frances storm track
Organization: GoMOOS: http://www.gomoos.org
WMS Service Online Resource: http://dev.gomoos.org/cgi-bin/wms_nhc?

Perfect. This resource URL is the gateway to the service providing the Frances storm track data. I punch the URL into my web browser, and add request=getcapabilities to the end: http://dev.gomoos.org/cgi-bin/wms_nhc?request=getcapabilities

This returns an XML document describing this Web Map Service (WMS). I zip down to the section describing the layers and find the Name of the layers they have available. ("grep Name" works a lot easier) Ah - two of the layers are hurricane layers.

Next, I turn to my MapServer configuration file (aka "map file"). I have several other WMS data sources already loaded in map file so I just copy and paste one of them and make a few changes. I change the resource URL to point to the gomoos URL. I change some layer settings to use the frances_track and frances_latest layers from that WMS service. A couple of HTML tweaks to my (admittedly spartan) mapping interface and I'm ready to go.

Back in the web browser, I point back to my site, et voila. Frances appears! Updates occur every six hours. If you zoom in you can see that the remote server even timestamped the tracked locations.

So what did this teach me? Well, it continues to build my confidence in the applicability of web services and open source solutions. Although I had to wade through a tiny bit of XML, it really didn't take any effort and only a few minutes to add a powerful little piece of data to my public site. Just think of the possibilities. Today, Frances. Tomorrow, gas prices in California - but that's a weblog for another day!

Tyler Mitchell is the author of Web Mapping Illustrated - a book focused on teaching how to use popular Open Source Geospatial Toolkits. He works as the Executive Director of the Open Source Geospatial Foundation, aka OSGeo.