Tuesday, November 30, 2010
Images shown in the Infrared give the opportunity to see beyond what the human eye cannot see. Images in the infrared show moisture content in the soil as well as healthy vegetation. This allowed for our group to take an even closer look at the trauma, and provided more evidence as to where exactly the destruction of the tsunami tore through Indonesia.
Using nightlight data, we were able to show the tsunami's destruction of heavily populated areas of the island. This allows us to identify how fast the people of the area were able to rebuild the damaged infrastructure, and places they found most favorable for the relocation of their towns.
Through the SRTM elevation map of Banda Aceh, we were able to see the areas of low elevation which were affected the most by water damage from the Tsunami. This gave us the oppurtunity to the areas affected most by water damage.
Through the use of these devices it has allowed us to witness the extent of destruction caused by the 2004 Tsunami and understand where and when rebuilding took place and where the relocation of people took place.
Borrero, Jose C. "Science Magazine: Sign In | Science/AAAS." Science. Web. 30 Nov. 2010. .
Brown, Paul. Tsunami cost Aceh a generation and $4.4bn. London: UK Guardian, January 2005. http://www.guardian.co.uk/world/2005/jan/22/tsunami2004.internationalaidanddevelopment
Chen, P., L. K. Kwoh, and S. C. Liew. Tsunami Damage Assessment Using High Resolution Satellite Imagery: A Case Study of Aceh, Indonesia. Tsunami Damage Assessment Using High Resolution Satellite Imagery: A Case Study of Aceh, Indonesia. Centre for Remote Imaging, Sensing and Processing, National University of Singapore, Lower Kent Ridge Road, Singapore 119260., 2005. Web. .
Miura, H., S. Inoue, and A. C. Wijeyewickrema. EVALUATION OF TSUNAMI DAMAGE IN THE EASTERN PART OF SRI LANKA DUE TO THE 2004 SUMATRA EARTHQUAKE USING REMOTE SENSING TECHNIQUE. Web.
Monday, November 29, 2010
To get a closer look at the tsunami’s effect on nightlight, we performed a change detection analysis, and created a difference map to easily see changes in lighting from before and after the tsunami. The map shows the light that was present in 2004 but went dim after the tsunami, as well as the new light that came about the year after the tsunami hit. The northwestern edge of the island displays blue (Nightlight Present in 2004 But Not 2005), while the northeastern edge displays red (Nightlight Present in 2005 But Not 2004). This reveals the relocation of the inhabitants from the west to the east, away from the destruction caused by the tsunami.
In order to get an even better view and understanding of the destruction in Indonesia, we must see past what the human eye can see, in a quite literal sense. In ENVI, we chose to look at the infrared bands. To be more precise, in the RGB scale, instead of looking at the red, green and blue bands, we placed one visible band, (band 3) in the red, band 5 in the green and band 4 in the blue, both of which are infrared.
Once this image was loaded, we produced our infrared images which would more clearly show the destruction and shows us what we cannot see with the human eye. When looking at the images in Infrared, the heat of the earth's surface is captured. When comparing the 2004 image to the 2005 image, the evidence of the tsunami's path is very clear, devastating the coast of Banda Aceh and flowing through the lowlands into Lhonga. The blue areas in the 2005 image show the destruction, for these are cool places that aren't giving off heat; it is land left in ruin. These areas are highlighted along the coastlines especially in Banda Aceh and Lhonga, where one can witness the removal of entire towns. When looking North, at the island of Pulau Peunasu the blue is highlighted deep into the land and shows the path the tsunami took on it's south shore.
The 2009 image captures how Banda Aceh has recovered from the Tsunami. At a quick glance one can see how the vegetation has returned and the reconstruction of the coastline has retained its linear form. Take a close look and there is evidence of new rebuilding and relocation of people. It looks like there are more areas devoted to agriculture closer to the coasts, while cities and towns seem to have been rebuilt at higher elevations and further from the coast.
In order to witness the destruction of the tsunami in 2004, we collected images before the tsunami hit, images a couple of months after the tsunami, and images from present day. These images were collected from a LANDSAT satellite which we downloaded for free off the internet. With these images, we used a program software ENVI, to manipulate the data, by first putting it into RGB color, which gives it color equivalent to what the human eye sees. In these images alone, one can see destruction very clearly.
The 2004 images, taken prior to the tsunami, shows Banda Aceh of Indonesia, very green and full of healthy vegetation. When placed side by side with the image taken in 2005 after the tsunami, it is very evident the amount of destruction Banda Aceh suffered. The three areas, in which we focused our study and gathered evidence from include, Banda Aceh, Lhonga, and Pulau Peunasu. Looking at the 2005 image the land is brown and barren, and this shows where the brunt of the devastation took place. The tsunami wiped out healthy vegetation and destroyed agricultural and residential land, leaving it in ruins. The coastline is another strong indicator of the power of this tsunami having been completely wiped out. It clearly doesn't have the same linear structure compared to the 2004 image. The image taken in 2009 is used to show how much the area has recovered since tsunami. The return of green, healthy vegetation shows that the ecosystem is recovering well, and appears very similar to the image taken prior to the disaster. It also shows the rebuilding and relocation of the people. There is a lot movement away from the coastline and relocation in places in higher elevation.