代写GGR 315 Environmental Remote Sensing, 2024 Assignment 2: Introduction to digital data interpretati
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Assignment 2: Introduction to digital data interpretation and processing
Questions
(100 marks, 10% of the final grade)
1. (5 marks) What is remote sensing?
2. (10 marks) What is reflectance, what is its range, what is its unit?
3. (15 marks) What are advantages and limitations for binary and text files? How many bytes does it take to store the following digital image in a binary file? How about to store
it in a text file?
|
120 |
10 |
227 |
|
15 |
140 |
24 |
|
32 |
20 |
150 |
4. (15 marks) The following are digital numbers (DN) in one line of a remote sensing image, show the new screen DN values of this line after contrast enhancement in a 6-bit range using the minimum/maximum linear stretch method.
10, 10, 24, 40, 31, 31.
5. (5 marks) Using the files in folder “LT50170302011184EDC00”, import the Landsat TM image into ArcGIS Pro, provide a screenshot or screen photo for the true color image on ArcGIS Pro (i.e., Red for band 3; Green for band 2; Blue for band 1).
6. (20 marks) Once the Landsat TM image is loaded into ArcGIS Pro, select any 3 sample pixels for each of the land cover types: vegetation, water body, and built area (please record the column and row for each of the pixels). (In total, you should select 9 pixels: 3 land cover types × 3 pixels perland cover type).
1) Find the digital numbers (DN) for band 2 at these 9 pixels. (In total, you should find 9 DNs: 3 land cover types × 3 pixels perland cover type). (3 marks)
2) Do the same as step (2) for band 4. (2 marks)
3) Calculate themean DN for each of the land cover types in band 2. (3 marks)
4) Calculate themean DN for each of the land cover types in band 4. (2 marks)
5) Compare and discuss your results for the three land cover types in band 2 and band 4, respectively. (10 marks)
7. (30 marks) Once the Landsat TM image is loaded into ArcGIS Pro, read the digital numbers (DN) for band 3 and band 4 from the following pixels (column, row):
(1920, 828), (1013, 3512), (3469, 5640), (4194, 4238), (5519, 4851), (2798,4972).
Convert DN values into reflected spectral radiance in W m-2 sr-1 μm-1 using the following sensor calibration equation,
Reflected spectral radiance = A0 + A1*DN
where the coefficients are A0=-4.5 and A1=0.63968 for band 3 and A0=-4.5 and A1=0.635294 for band 4. These coefficients have the same unit of Wm-2 sr-1 μm-1 . Calculate the spectral irradiance for the reflected radiation from these pixels assuming that the pixels are isotropic reflectors (Lambertian surface). Make sure to report the unit.