Articles published for Earthzine’s Disaster Management theme (Dec. 21, 2010-March 20, 2011) address efforts to…
Sharp Look from Orbit
- Published on Thursday, 28 January 2010 00:01
- Christoph Aubrecht
- 0 Comments
Translated and adapted from the German by Christoph Aubrecht.
Originally published in Der Standard (Vienna, Austria) as “Scharfer Blick aus dem Orbit” by Karin Krichmayr (DER STANDARD, print edition, 20 January 2010).
Photos and article reprinted with permission or in the public domain.
Satellite Images Showing the Destruction Caused by the Earthquake in Haiti Have Gone Around the World
They are interpreted by geoinformation scientists, who provide new perspectives not only for disaster management, but also in cases of crises and conflicts.
Dirk Tiede currently works on satellite images of Haiti all day. The expert from the Center for Geoinformatics Salzburg (Z_GIS) was commissioned by the Red Cross and a UN-organization to create damage maps and analyses of road passing possibility. Currently he is working on the southern part of the disaster area which has been less covered so far, in order to provide the relief organizations’ estimates as quickly as possible of the damage that the January 12 earthquake has caused.
“When a disaster strikes, the most important information is always first manually interpreted from the imagery. We try to process the satellite images and improve the algorithms in a way that damage information can be extracted automatically,” explains Tiede, who is involved in “rapid mapping” activities (i.e. the rapid provision of maps for crisis management) in the context of the EU-project G-Mosaic. “Now it is important, above all, to carry out pre-post disaster comparisons as quickly as possible, in order to identify the areas suffering greatest destruction.”
Since the earthquake struck the island, satellite images are being passed around the world and illustrate the full extent of the damage. Google Earth users post information and link it with pictures. Professional analysis of space-based data is however carried out by geoinformation scientists. Spatial representation, combined with the visualization of population, transportation networks, hospitals, etc., serve as important decision support for relievers. Although there are still problems in Haiti in terms of distribution of food and means: “The data situation is much better than it was, for example, with recent earthquakes in Pakistan or China,” Dirk Tiede states.
A Question of Resolution
“Satellite images feature higher resolution than ever, you can zoom in to half a meter. Moreover, they are provided for free by commercial satellite operators,” Tiede emphasizes. This is becoming more self-evident, also, thanks to the International Charter Space and Major Disasters, which commits its members to rapid dissemination of satellite images in case of disaster.
“Quickly getting high-resolution images that are not affected by extensive cloud cover or rain often is the biggest challenge,” says Christoph Aubrecht, geoinformation scientist at the Austrian Institute of Technology (AIT). In addition, satellites do not pass over a given location at any time. Radar satellites are weather independent. Furthermore, laser scanners can deliver important information: Pulses are emitted from an airplane and the reflections provide accurate information on ground conditions (e.g. height differences) and hence destruction. “This is, however, extremely expensive,” admits Aubrecht.
Models for Earthquake Risk
In a recent project Aubrecht works with Portuguese colleagues on creating models of earthquake risk regarding the population in the metropolitan region of Lisbon. “Normally census data are considered for those kinds of analyses, but they only tell you where people are at night,” Aubrecht explains. “We additionally consider commuting statistics and work places, and are hence able to assess how many people are staying in the danger zones.” That way it can be determined which areas would be most affected by an earthquake – depending on day– or night-time.
The work of geoinformation scientists not only plays a role in disaster management, but also in security policy, such as in monitoring and evaluation of regional crises and conflicts. Taking the refugee camp in Sudan’s Darfur as example, Peter Zeil, project manager at Z_GIS, together with his team, has developed methods to assess population numbers based on satellite data. “The idea is to show how refugee camps develop and how they impact the environment and resources such as firewood, agricultural land being essential for food security and water resources,” Zeil explains.
Based on experience from past events, geoinformation scientists try to assess the risk of future conflicts in advance and find corresponding indicators. “We might for example examine whether there is a relationship between environmental factors such as desertification or excessive land use and conflicts,” says Zeil. “The exploitation of natural resources is clearly linked to such conflicts. Using satellite data, we are observing illegal mining of metals and illegal felling of trees.”
Spatial data can also be used to protect strategic infrastructure or to create criminal profiles. Within the framework of the security research program, KIRAS promoted by the Austrian Federal Ministry for Transport, Innovation and Technology, the Research Studio iSpace developed a study on what geographic information can contribute. Researchers are e.g. tracking serial burglars or using sensors to monitor the current status of public security. “Measurement stations can automatically send a message when a suspicious value is recorded,” iSpace director Thomas Blaschke explains. Currently, the eyes of geoinformation scientists are focused on Haiti – in order to be better prepared for the next disaster.
(Karin Krichmayr / DER STANDARD, print edition, 20 January 2010)