GEOM30009 IMAGING THE ENVIRONMENT
Department of Infrastructure Engineering
Assignment 1
Image Interpretation
Due Date: 11:55 pm on Friday of Week 3
Value: 15% of Subject Mark
Objective
The purpose of this assignment is to learn how to visually interpret satellite images and identify various features and land cover types. You will learn that using certain cues and indicators will assist you in image interpretation and identification of different features.
Background
Aerial and satellite images are invaluable sources of information for understanding our natural and built environments. However, certain characteristics of aerial and satellite images makes their interpretation and understanding less straightforward. Specifically, the angle and altitude at which aerial and satellite images are taken are vastly different from the horizontal ground level views that we are used to, giving an unfamiliar perspective to what may otherwise be a normal image. Additionally, most airborne and spaceborne cameras can capture wavelengths of light beyond the visible spectrum, such as infrared. Consequently, different features and objects may not necessary appear in their natural colour.
Because of such issues, we use the following basic indicators to assist visual interpretation and feature identification while analysing aerial and satellite images:
1. Tone/Hue/Colour – the relative brightness/colour of features. For example, in a natural colour image dense healthy vegetation usually appears dark green, whereas grassland appears light green.
2. Texture – what gives us the impression of smooth or rough texture. For example, water is characterised by a smooth texture, whereas sand dunes have a rough texture.
3. Shape – regular geometries generally signify human influence (e.g. Buildings)
4. Size – scale and shadows
5. Pattern – consider how trees in a park may form. no regular pattern, but trees along a roadside have a linear pattern.
6. Associations – features that belong and don’t belong together (e.g. Oil refineries will not be in a residential area).
7. Location – knowledge about the location of the image can help identify its features (e.g. snow and ice in an image of polar regions).
Data
Five images, which have been uploaded in Canvas, will be used for this assignment. The dataset can be downloaded from Canvas under “Assignment 1: image interpretation” .
Tasks
Your task is to visually analyse each of the five images and identify the main features using the above indicators, i.e., tone, texture, shape, size, shadow, pattern, location and association. Note that some images might be false-colour (i.e., features may not appear in natural colour).
HINT: Each image has a .txt file next to it containing information about the sensor, spatial resolution, time and location. Please make sure you download both the jpg and the txt file.
Submission
We expect you to write a 600 words scientific report and include the following content. You can add more words if necessary BUT please keep it less than 2000 words.
Your report should consist of seven sections as bellow:
a. Introduction
b. Image 001: Discussion
c. Image 002: Discussion
d. Image 003: Discussion
e. Image 004: Discussion
f. Image 005: Discussion
g. Conclusion
2. Provide a proper introduction to address the purpose of image interpretation and clearly state the aim of your report.
3. Provide one paragraph discussion for each image including the following content:
a. Describe the main features (at least five per image). For each feature, mention at least two indicators that help you identify it.
b. Explain how you distinguish features with similar appearances, e.g. ice, cloud, and smoke. If a feature appears in an unnatural (false) colour, explain why it appears that way.
c. When referring to a certain feature mention where it is in the image (e.g., top- left corner, bottom-centre, etc.).
d. If you explained a feature in an image you do not need to explain it again for another image using the same indicators. For example, if you explained a water body in an image, try to focus on other features in the next image (e.g. vegetation, roads, etc.) and explain those.
e. Your discussion should be based on visual interpretation. However, you can do an internet search (e.g., using the time and location of image capture) to support your interpretation.
4. In the conclusion section reflect on your findings and what you learned about image interpretation.
5. Provide a reference list if your text includes any information from other sources.
Submit a digital version of your report via Canvas and in pdf format only.
Marking rubric
Appropriate length and proper formatting 5%
Proper introduction 10%
Proper discussion of image 001 15%
Proper discussion of image 002 15%
Proper discussion of image 003 15%
Proper discussion of image 004 15%
Proper discussion of image 005 15%
Logical conclusions 10%