Thursday, 13 March 2014

Remote Sensing. Cell Value. Traverse Profile. Scattegrams.

1. How can remote sensing help in searching of MH370?
          Remote sensing can help to search for MH370 over the air and sea due to the application of satellites. Satellites can be used to capture images of the surface of the Earth of where the plane is estimated to have passed by. Images can also be taken in fixed intervals at certain places so that the place is well observed. Images taken can be processed using the application of GIS, which is able to provide the exact coordinates, given that the map of the Earth is present. Besides, remote sensing helps in searching efficiently because it can search at a large area at once and take only a short time. Therefore, remote sensing can save searching time as it can get images of places where people reported to have seen the place without having the rescue team to go in person, which will take more time.


2. Cell value profiles windows. How it works and what it shows.
          Cell value is the value of a particular data in each cell or grid, normally known as pixel as well, of an image. It shows also values of each cell or grid of each band in a multi-bands image. Cell values can be of high resolution or of low resolutions depending on the satellites. By selecting a particular area desired, values of each cells according to bands will be shown. Below is attached with the figure of the values of cells by randomly selected point.

Figure 1 shows the cell values of a randomly selected point.


3. Traverse profiles. How it works and what it shows.
          Traverse shows the profile of different lines. Different lines can be formed according to the desire of the user on what he or she wants to interpret of the image. When a line is formed, a graph will be shown and it can be changed into different  bands, and graphs will change accordingly. Many lines can be formed and line profiles can be viewed and compared easily. Below attached are images of some steps of viewing traverse profiles.

Figure 2 shows map before the line is formed.

To show the line profiles, poly line icon from the tool bar must be selected, then click on two desired points. Once two points are selected and line is formed, a graph will be shown together with the details below it. And it can be changed to different bands.

Figure 3 shows the lines and its profiles.


4. Scattegrams. How it works and what it shows.
          Scattegram image is a profile of data which shows the correlation between different bands. Correlation between two bands can be shown by the plotting of X-axis and Y-axis. The region with red colour in the image represents the correlation of two selected bands. The larger the red region, the more is the correlation between the two bands. Below attached are pictures showing how scattegram image works.

Figure 4 shows the scattegram image which shows the correlation between the data of band 1 and band 2.

Bands to be compared can be changed by clicking on the set up button, and change the X-axis and Y-axis. The red region shows the correlation between two bands.

Figure 5 shows the correlation between band 4 and band 5.


Sunday, 2 March 2014

Importance of Algorithm in Remote Sensing

Algorithm is one of the functions in remote sensing. It helps to process raw data obtained into data that can be read and understandable to all. It uses Einstein's equation to convert or process data. It can be converted into 2D or 3D data, which helps users to further understand and analyse more of the data. 

In 3D data, image can be rotated front and back, left or right, in order to assist analysis. Several function can be selected and randomised in order to change the structure of the 3D data. Colour of the data can be changed according to user's choice. In algorithm, there are seven bands, from band 1 to band 7. The higher the band, the clearer is the image. However, it only applies until band 5. For band 6 and 7, image will remain unclear.

I felt excited and happy through this learning process because it is very interesting. I am eager to learn more on this application so that I can further analyse any data to then create maps for many users in all forms. ^^