Katrina Maps and Photos Delivered Using OGC Web Service Interface Standards

At the second MapServer Users Meeting and the first ever North American Open Source GIS Conference that was held June 9th to 11th 2004 in Ottawa, Ontario, Canada, Norman Vine, a software developer working with the University of New Hampshire and the Woods Hole Oceanographic Institute, demonstrated a prototype Google Earth-like planetary viewer using multiple datasets. Norman was looking for others who might be interested in turning this into an OGC compliant widget that could use servers implementing the OpenGIS Web Map Server (WMS) Specification as data sources, in addition to "pre-cooked" locally stored files.

This widget attracted quite a bit of attention. Mark Lucas of L3-Titan, project leader for the Open Source Software Image Map (OSSIM, pronounced "awesome") toolset, saw the potential in this widget and volunteered his team to assist in developing it. This project is now known as osgPlanet. It is a cross platform Open Source project, and has been rewritten on top of the OSSIM library.

Norman was invited to present osgPlanet as one of the kickoff talks at this year's Mapserver Users meeting and it was very well received, but he said that its release was somewhat overshadowed by Google releasing Google Earth a few weeks later.

The katrina.telascience.org project is a direct result of the vision of using WMS as a data source for osgPlanet or similar "web enabled seamless mosaic viewers" based on open standards, and the expertise osgPlanet's development team acquired in preparing datasets for osgPlanet prepared them for the Katrina effort.

Background – World Wind

NASA's World Wind project is a 3D planetary visualization system that overlays satellite imagery with weather, political, and topological map data. Users can zoom in from outer space and "fly around," much as they can with Google Earth. But unlike Google Earth, World Wind is open source. The World Wind site provides access to some data sets that are hosted at San Diego State University's Visualization Center and other data sets that are hosted on TerraServer.

One of the first add-ons developed by third-party programmers for World Wind was a plug-in that enables clients to request data from any map server that implements OGC's WMS specification. A featured World Wind base map is NASA's WMS-accessible Global Mosaic, which serves full resolution (15m), pan-sharpened Landsat for any land spot on the globe - higher geo-coverage than Google Earth. It does false-color rendering of any band combination using the OpenGIS® Styled Layer Descriptor (SLD) Specification, a specification that extends WMS to allow user-defined symbolization of feature data. Global Mosaic was funded by NASA's Geospatial Interoperability Program and implemented by Lucian Plesea of NASA's Jet Propulsion Laboratory.

After the storm

Immediately after Hurricane Katrina passed over New Orleans, the US National Oceanic & Atmospheric Administration (NOAA) used an airborne camera to acquire a set of 1,500 JPEG images of the storm-damaged Gulf Coast. A NOAA systems administrator posted a note on the World Wind IRC channel that NOAA would be making the post-storm over-flight imagery available and suggested that perhaps someone could make a World Wind add-on from it. Norman Vine responded that he could get it into geotiff form so it could be served by a server through a WMS interface.

Vine worked with Garrett Potts of L3-Titan to prepare and mosaic the data using OSSIM. Working with the NOAA data and with assistance from NOAA staff, Vine and Potts created a useful product in half a day, which was an extraordinary feat, given the size of the data set. This is a testament both to their commitment and to the capabilities of OSSIM.

A World Wind Developer provided Norman with a utility that he used to turn the geotiffs into a World Wind data pack that was made available on the World Wind site.

Most users of this data wouldn't have an image processing package to use with downloaded data files, so Vine and Potts assembled a set of web mapping servers based on WMS. John Graham, from San Diego State University's Visualization Center, arranged for the Visualization Center to provide the high bandwidth and massive storage required to serve up the map images. John Graham had stood up Telascience.org at the Visualization Center several years earlier to provide free hosting and support for research and educational projects from NASA, National Science Foundation, World Resources Institute, WorldLink Media, Caltech, Naval Postgraduate School, Planetwalk.org (UN Goodwill Ambassador to the Environment), the US Navy, and many other agencies and organizations. The Visualization Center maintains a number of powerful multiprocessor servers on the University's OptIPuter 10 gigabit network, which enabled much faster processing of the images.

The Katrina maps were served up using a variety of methods prepared by Vine, Graham and others. The server that implements WMS is implemented with the University of Minnesota's open source web mapping toolkit, MapServer. The WMS interface enables a wide variety of applications to access the data on the Visualization Center's server.

For visitors who want to access the website and pan and zoom using only a web browser, the developers set up an HTML/CGI application that allows interactive viewing, again leveraging the local server's WMS interface. This web application is an implementation of the open source Chameleon map interface, an advanced WMS client that allows users to add to the map other layers from other servers on the Web that implement WMS.

Howard Butler brought in the ability to do geocoding, using Schuyler Erle's open source "geocoder.us" TIGER database query technology based on the US Census Bureau's TIGER street data. On the main page on http://katrina.telascience.org there is a portlet called "Check my house" that enables a user to enter an address and see the imagery for that location.

This geocoding capability was quickly put to use by the US Navy, who used it to geographically locate military personnel as well as civilian employees and their extended family who were located in the disaster area. Residential addresses were processed through the geocoder and plotted in two and three dimensional geographical displays for Navy decision makers.

Basic web maps in which users could overlay data layers such as highways and political boundaries on the imagery were available to website visitors within 48 hours after Vine and Potts received the imagery, and development has continued.

NIEHS Maps

One important addition to Telascience's Katrina spatial data clearinghouse was a collection of datasets from the US National Institute of Health's National Institute of Environmental Health Sciences (NIEHS). The Telascience-hosted NIEHS map site gives direct access to the server described above, and the site is also reachable from a link on the NIEHS website. With the addition of NIEHS map layers such as Hazardous Air Pollutants; Metals and Metal Compounds; Chemicals Industry Facilities; OSHA Carcinogens; and Persistent, Bioaccumulative, and Toxic Chemicals, the Telascience server now provides 46 Katrina-related data layers through the open WMS interface and through the browser application.

Looking to the future

Much of the work that was done to provide maps and images for the Katrina relief effort can be reused in future relief efforts. The volunteer effort has produced not only software and data, but organizational connections that will be helpful when (not if) other hurricanes cause devastation along the Gulf Coast.

These lessons learned about best practices are apparent: Any data that might be useful in disaster management ought to be available on a server or servers that have open interfaces, At a minimum, these should be interfaces that implement the WMS specification for access to map images. Also, the data and its server should be discoverable by means of standards-based, XML-encoded metadata registered in a catalog that conforms to the OpenGIS Catalog Services Specification. Geospatial One-Stop and USGS's The National Map provide such catalogs. When critical data is accessible via open interfaces and is discoverable through a catalog that anyone can use, the data has much more value in efforts to save lives, property, and ecosystems. Expert volunteer geospatial technologists will still be needed, but their time will be applied more productively if they can use this relatively simple infrastructure. The technology for this life-saving, money-saving disaster mitigation infrastructure is already available. It just needs to be deployed at local, state and federal levels.