Bringing together satellite images and mapping data is one way the technology world can help the people of New Orleans, says technology analyst Bill Thompson.
When natural disasters happen in remote, isolated parts of the world it is often impossible for those not directly involved to have any real idea of the extent of the damage or the suffering of the people involved.
Google maps can be used in helpful ways
This is not the case with the devastation caused to New Orleans and other parts of Louisiana by Hurricane Katrina where an area of about 90,000 sq miles (234,000 sq km), the size of the United Kingdom, has been affected.
We have had comprehensive news coverage since Katrina hit the US Gulf coast on Monday, and both online and offline media are reporting on events in New Orleans, where law and order seem to be breaking down in the flooded and inaccessible city.
Those who have access to the internet within the affected area are posting blog entries and photographs, and sites like Craigslist are being used to help people locate relatives.
In the United States people are accustomed to being in control and to having what they want, when they want it.
This has its downsides, as we see too often in international politics, climate control agreements or deciding who runs the internet, but in times of adversity it is a spirit that can leave the rest of the world astonished at the level of innovation, energy and resolution that emerges.
We can see this in the way the net is being used to help those affected find out what has happened to their homes and neighbourhoods, and the imaginative way they are using new web-based mapping tools to do this.
In September 2001 satellite photographs of the collapsed towers, with a plume of smoke drifting downwind, were among the most chilling images of the destruction of the World Trade Centre.
At the time these images were comparatively unusual, but it is now very easy to access such photographs even at the high resolutions that were previously reserved for military or government use.
The news media are using lots of satellite images to illustrate their coverage.
CNN has a selection of views, the BBC has its own graphic of the New Orleans area, and photographs from those caught up in the hurricane and subsequent flooding are everywhere on news sites, in TV shows and in the newspapers.
The people of New Orleans want more, and it seems to have passed to the web community to provide the sort of detailed information that they are after.
For example Kathryn Cramer, a blogger from New York state, has pulled together a selection of before and after images which show details of the damage, while another blogger, Tim Holtt, has built his page so that moving a mouse over each image swaps between "before" and "after".
But the real interest is in the "mashups", websites that are combining the latest satellite imagery with maps and geodata to provide information on a more local scale.
Using maps and images provided through Google Maps and Google Earth, a number of hackers are building detailed models of the flood-damaged areas.
This is not just a frivolous use of new toys by geeks with too much time on their hands. These experiments can help people find out whether their house is under water, which streets are accessible and what has happened to their neighbourhood.
The map at Scipionus.com is probably the best example, but there are many more.
I have expressed my doubts about Google's mapping project in the past, because they do not use the emerging international standards for geodata, and so there is no guarantee that applications built on top of the maps service will continue to work when Google changes it.
But the sheer usefulness of these mashups is the clearest possible example of how online access to high-quality geographical data is going to change the world.
Next time we see a disaster of this scale, wherever it happens in the world, we can expect the news media to pick up the innovations being made by the mappers and programmers, helping them to provide clearer, more useful and more comprehensive coverage.
Just as journalists have learned from bloggers how to get closer to their audience, these new mapping tools will help us convey the extent of damage more clearly, and also help local news services provide direct assistance to those affected.
Of course these maps, the weblogs and the news reports are of little help to the people trapped in the affected area since they do not have electricity, computers, net access or - by this stage - working mobile phones or handheld computers.
They may be able to get free wireless access if they can find a working access point, and there are moves afoot to provide e-mail and net access to those who have been evacuated, but this is still some way off for most.
Net zealots will often tell you that the internet was "designed to survive a nuclear war", but they tend to forget that this only applies to the computers outside the area that has actually been destroyed.
So while the internet is working well outside the flooded areas of Louisiana, that provides little comfort to the thousands of people trapped in the Superdome.
The army is reported to have brought in its own communications systems, recognising that they cannot rely on the civil infrastructure.
Perhaps when New Orleans is rebuilt, as it surely will be, the communications services will be hardened against flood and other disasters. After all, in the modern world being online is probably as important as having electricity.
Bill Thompson is a regular commentator on the BBC World Service programme Go Digital