Homework Assignment#4 (Final Submission)

STHT 506 - GEOGRAPHIC INFORMATION SYSTEMS

Homework Assignment#4 (Final Submission)

Requirement:

(a) Perform a Raster Merge on the four satellite images of FAS_China3.tiff, FAS_China4.tiff, FAS_China5.tiff and FAS_China6.tiff.

(b) Perform a Raster Extract covering the areas of the Taiwan Strait and Taiwan Island.

(c) Use the vector data for the boundaries of Taiwan's cities and counties.

(d) Display air pollution data for Oct and Nov (2012?), using Pseudocolor; Spectral (Blue to Red).

(e) Perform Raster Calculator to display the change of pollutants between those two months.
(f) Suggest some parts of Taiwan that are less hazardous to stay/live during those bad air quality days.

ANSWER - PART (a)

Perform a Raster Merge on the four satellite images of FAS_China3.tiff, FAS_China4.tiff, FAS_China5.tiff and FAS_China6.tiff.

Step: After loading in the 4 satellite images (FAS_China3.tiff, FAS_China4.tiff, FAS_China5.tiff and FAS_China6.tiff), then used the function "Merge" under "Raster", and selected the 4 files and created a file named "FAS_China Merge", to get the merge image.

ANSWER - PART (b)

Perform a Raster Extract covering the areas of the Taiwan Strait and Taiwan Island.

Step 1: Opened the function "Clip Raster By Extent..."

Step 2: Selected the "FAS_China Merge" image, then used the function "Draw on Map  Canvas" in clipping extent", and saved the output file as "FAS_China Taiwan" in "Clipped (extent)", then clicked "Run" to get the areas of the Taiwan Strait and Taiwan Island. 

Step 3: Unselected the file "FAS_China Merge" so to focus on the selected Taiwan area only. 

ANSWER - PART (c)

Use the vector data for the boundaries of Taiwan's cities and counties.

Step: Loaded in the data file of "台灣邊界圖" and "台灣縣市圖", selected the color under "Symbology" in "properties" to showcase the boundaries of Taiwan's cities and counties.

ANSWER - PART (d)

Display air pollution data for Oct and Nov (2012?), using Pseudocolor; Spectral (Blue to Red).

Step 1: Loaded in the air pollution date for Oct "pm10_Oct.asc", and change the Render Type in "Symbology" to "Singleband pseudocolor", selected "Discrete" under "Interpolation", selected "Spectral" in "Color ramp" and used the "Invert color ramp" function to change the color to "from Blue to Red", then selected "classify" and got the performance of air pollution in Oct.

Step 2: Loaded in the air pollution date for Nov "pm10_Nov.asc", and applied previous steps to get the air pollution performance in Nov.

ANSWER - PART (e)

Perform Raster Calculator to display the change of pollutants between those two months.

Step 1: Used "Raster Calculator" in "Raster" to find the air pollution difference between Oct and Nov (Remarks: function = air pollution in Oct - Nov) and saved the file name as "air pollution difference".

Step 2: Used same steps mentioned in part (d) to display the air pollution difference.

ANSWER - PART (f)

Suggest some parts of Taiwan that are less hazardous to stay/live during those bad air quality days.

In conclusion: based on the data provided, 3 areas (1. north part of "南投縣", 2. area between "嘉義市"、"南投縣" and 高雄市", and 3. north part of "台東縣") are suggested to stay during those bad air quality days as all these 3 areas showed low air pollution in both Oct and Nov. Some of the areas like east of ""花蓮縣" and east of "宜蘭縣" can also be considered to stay in Oct.